Android ApiDemo 笔记（一）Content与Graphics

Android ApiDemo 笔记（一）Content与Graphics

http://blog.csdn.net/wufenglong/article/details/5596402

一.package com.example.android.apis.content;

1.ReadAsset:从asset目录里读出

2.ResourcesSample：在values的strings.xml里取得string,

以及在非activity里取得方法。

Resources res = context.getResources();
CharSequence cs = res.getText(R.string.styled_text);

3.StyledText:在TextView里直接setText带有styled的字符串<string name="styled_text">Plain, <b>bold</b>, <i>italic</i>, <b><i>bold-italic</i></b></string>

二.package com.example.android.apis.graphics;

1.AlphaBitmap：应用Paint p.setAntiAlias(true);//抗锯齿，如果没有调用这个方法，写上去的字不饱满，不美观，看地不太清楚

下图为p.setAntiAlias(false)效果

下图为p.setAntiAlias(true)效果

1.1 p.setAlpha(0x80);//透明度

1.2 p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));//14例中FingerPaint:手写板有这个用法

1.3 p.setTextSize(60);//设置字体大小

1.4 p.setTextAlign(Paint.Align.CENTER);//基准线

1.5 InputStream is = context.getResources().openRawResource(//从drawable里的图片转到bitmap
R.drawable.app_sample_code);
mBitmap = BitmapFactory.decodeStream(is);

1.6 mShader = new LinearGradient(0, 0, 100, 70, new int[] { Color.RED,//渐变
Color.GREEN, Color.BLUE }, null, Shader.TileMode.MIRROR);

p.setShader(mShader);

2.AnimateDrawables把一张照片动起来，类似跑马灯的效果，有三个类AnimateDrawables ，AnimateDrawable，ProxyDrawable

2.1 Drawable dr = context.getResources().getDrawable(R.drawable.beach);//获得Drawable
dr.setBounds(0, 0, dr.getIntrinsicWidth(), dr.getIntrinsicHeight());//设置图的边界，有放大缩小的作用这是设置为100，100的边界效果

2.2 Animation an = new TranslateAnimation(0, 100, 0, 200);//从0，0点到100，200移动的动画
an.setDuration(2000);//持续时间2秒
an.setRepeatCount(-1);//无限循环

2.3 public void draw(Canvas canvas) {
Drawable dr = getProxy();
if (dr != null) {
int sc = canvas.save();//
Animation anim = mAnimation;
if (anim != null) {
anim.getTransformation(AnimationUtils.currentAnimationTimeMillis()//动起来
mTransformation);//该方法根据当前间 (currentTime) 和 interpolator，计算当前的变换，在 outTransformation 中返回
canvas.concat(mTransformation.getMatrix());//对canvas应用矩阵变换
}
dr.draw(canvas);
canvas.restoreToCount(sc);
}
}

注意：canvas.save();//canvas.restoreToCount(sc);是正对出现的
假设我们将要对canvas进行了一系列的设置，例如旋转，变色等，而又不希望在操作完之后让这些设置影响到后面的绘画。
就需要在设置前先save，使用完之后再restore；带count的恢复，是指直接回复到某个状态

假设我们设置了clip去绘画一张图片的一小部分
一般这么干
canvas.save();
canvas.setclip
canvas.drawBitmap
canvas.restore();

3. Arcs：

3.1 mPaints[0] = new Paint();
mPaints[0].setAntiAlias(true);
mPaints[0].setStyle(Paint.Style.FILL);
mPaints[0].setColor(0x88FF0000);
mUseCenters[0] = false;

mPaints[1] = new Paint(mPaints[0]);
mPaints[1].setColor(0x8800FF00);
mUseCenters[1] = true;

mPaints[2] = new Paint(mPaints[0]);
mPaints[2].setStyle(Paint.Style.STROKE);
mPaints[2].setStrokeWidth(4);
mPaints[2].setColor(0x880000FF);
mUseCenters[2] = false;

3.2 canvas.drawArc(oval, mStart, mSweep, useCenter, paint);//useCenter为是否画中心。mStart起始度数，mSweep跨度

4.BitmapDecode：最下面的国旗是GIF动画

4.1 两种加载图片，再转成bitmap的方法

// now opts.outWidth and opts.outHeight are the dimension of the
// bitmap, even though bm is null

opts.inJustDecodeBounds = false; // this will request the bm
opts.inSampleSize = 4; // scaled down by 4 面试变成1/4大小
bm = BitmapFactory.decodeStream(is, null, opts);

mBitmap = bm;

// decode an image with transparency
is = context.getResources().openRawResource(R.drawable.frog);
mBitmap2 = BitmapFactory.decodeStream(is);

4.2 mBitmap2.getPixels(pixels, 0, w, 0, 0, w, h);//获得mBitmap2的像素颜色值，赋值给pixels，第三个参数为一行的像素数（矩形的宽）

mBitmap3 = Bitmap.createBitmap(pixels, 0, w, w, h,
Bitmap.Config.ARGB_8888);//用上面的pixels颜色数组创建一个Bitmap

4.3 mDrawable = context.getResources().getDrawable(R.drawable.button);
mDrawable.setBounds(150, 20, 300, 100);//设置button9的面积（只有Drawable才有这个方法）

4.4 canvas.drawBitmap(mBitmap4, 210, 170, null); //Bitmap的画法

mDrawable.draw(canvas);//Drawable的画法

4.5 is = context.getResources().openRawResource(R.drawable.animated_gif);//获得GIF动画流

mMovie = Movie.decodeStream(is);//把流转成Movie

//画Movie动画

long now = android.os.SystemClock.uptimeMillis();//当前时间
if (mMovieStart == 0) { // first time
mMovieStart = now;
}
if (mMovie != null) {
int dur = mMovie.duration();//GIF持续时间
if (dur == 0) {
dur = 1000;
}
int relTime = (int) ((now - mMovieStart) % dur);
mMovie.setTime(relTime);
mMovie.draw(canvas, getWidth() - mMovie.width(), getHeight()//画动画，参数为X,Y点
- mMovie.height());
invalidate();//刷新，不停的画
}

5. BitmapMesh：(没看)

5.1 mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.beach); //生成Bitmap

6.BitmapPixels：（没看）

7. CameraPreview：（没看）内容同SDK开发大全中的7.15例

7.1 // Hide the window title.隐藏标题
requestWindowFeature(Window.FEATURE_NO_TITLE);

8. Clipping：

8.1

//定好样式

mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(6);//画笔的宽
mPaint.setTextSize(16);
mPaint.setTextAlign(Paint.Align.RIGHT);

canvas.drawLine(0, 0, 100, 100, mPaint);//画线画的线为mPaint指定的宽度

8.2

canvas.save();
canvas.translate(160, 10);
canvas.clipRect(10, 10, 90, 90);
canvas.clipRect(30, 30, 70, 70, Region.Op.DIFFERENCE);
drawScene(canvas);
canvas.restore();

8.3

canvas.save();
canvas.translate(10, 160);
mPath.reset();
canvas.clipPath(mPath); // makes the clip empty
mPath.addCircle(50, 50, 50, Path.Direction.CCW);
canvas.clipPath(mPath, Region.Op.REPLACE);
drawScene(canvas);
canvas.restore();

9. ColorFilters：

9.1

Paint.FontMetrics fm = mPaint.getFontMetrics();//不知道是什么意思？？？？？？
float mPaintTextOffset = (fm.descent + fm.ascent) * 0.5f;

9.2

mColors = new int[] { 0, 0xCC0000FF, 0x880000FF, 0x440000FF, 0xFFCCCCFF,
0xFF8888FF, 0xFF4444FF, };

mModes = new PorterDuff.Mode[] { PorterDuff.Mode.SRC_ATOP,//过滤器的方式
PorterDuff.Mode.MULTIPLY, };
mModeIndex = 0;

filter = new PorterDuffColorFilter(mColors [i], mModes[mModeIndex]);//用mColors [i]和porter-duff mode的颜色创建一个颜色过滤

mDrawable.setColorFilter(filter);
mDrawable.draw(canvas);

10.ColorMatrixTest

private void setContrast(ColorMatrix cm, float contrast) {
float scale = contrast + 1.f;
float translate = (-.5f * scale + .5f) * 255.f;
cm.set(new float[] { scale, 0, 0, 0, translate, 0, scale, 0, 0,
translate, 0, 0, scale, 0, translate, 0, 0, 0, 1, 0 });
}

ColorMatrix cm = new ColorMatrix();

mAngle += 2;
if (mAngle > 180) {
mAngle = 0;
}

float contrast = mAngle / 180.f;

setContrast(cm, contrast);
paint.setColorFilter(new ColorMatrixColorFilter(cm));//设置颜色过滤
canvas.drawBitmap(mBitmap, x + mBitmap.getWidth() + 10, y, paint);
invalidate();

11.Compass指南针：（没看）

12.CreateBitmap：

12.1 创建颜色数组（说实话没看懂）

private static int[] createColors() {
int[] colors = new int[STRIDE * HEIGHT];
for (int y = 0; y < HEIGHT; y++) {
for (int x = 0; x < WIDTH; x++) {
int r = x * 255 / (WIDTH - 1);
int g = y * 255 / (HEIGHT - 1);
int b = 255 - Math.min(r, g);
int a = Math.max(r, g);
colors[y * STRIDE + x] = (a << 24) | (r << 16) | (g << 8) | b;
}
}
return colors;
}

12.2

private static Bitmap codec(Bitmap src, Bitmap.CompressFormat format,
int quality) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
src.compress(format, quality, os); //压缩

byte[] array = os.toByteArray();
return BitmapFactory.decodeByteArray(array, 0, array.length);
}

mJPEG[i] = codec(mBitmaps[i], Bitmap.CompressFormat.JPEG, 80);//用JPEG编码

13.DensityActivity

13.1

1:LinearLayout root =newLinearLayout(this);//设置一个线性布局root

2:root.setOrientation(LinearLayout.VERTICAL);//方向垂直

3:

4:LinearLayout layout =newLinearLayout(this);//在root布局内，又建一个layout布局

5:addBitmapDrawable(layout, R.drawable.logo120dpi,true);//以logo120dpi为View的背景，并把view加下布局

6:

7:

8:addBitmapDrawable(layout, R.drawable.logo160dpi,true);

9://addBitmapDrawable(layout, R.drawable.logo240dpi, true);

10:addLabelToRoot(root,"Prescaled bitmap in drawable");//加入一个TextView到root

11:addChildToRoot(root, layout);

12:setContentView(scrollWrap(root));

13:

14:}

15:

16:

1:private voidaddLabelToRoot(LinearLayout root, String text) {

2:TextView label =newTextView(this);

3:label.setText(text);

4:root.addView(label,newLinearLayout.LayoutParams(

5:LinearLayout.LayoutParams.FILL_PARENT,

6:LinearLayout.LayoutParams.WRAP_CONTENT));

7:}

8:

9:private voidaddChildToRoot(LinearLayout root, LinearLayout layout) {

10:root.addView(layout,newLinearLayout.LayoutParams(

11:LinearLayout.LayoutParams.FILL_PARENT,

12:LinearLayout.LayoutParams.WRAP_CONTENT));

13:}

14:

15:

16:privateBitmap loadAndPrintDpi(intid,booleanscale) {

17:Bitmap bitmap;

18:if(scale) {

19:bitmap = BitmapFactory.decodeResource(getResources(), id);

20:}else{

21:BitmapFactory.Options opts =newBitmapFactory.Options();

22:opts.inScaled =false;

23:bitmap = BitmapFactory.decodeResource(getResources(), id, opts);

24:}

25:returnbitmap;

26:}

27:

28:

//将bitmap为作View的背景，并把view加下布局

1:private voidaddBitmapDrawable(LinearLayout layout,intresource,

2:booleanscale) {

3:Bitmap bitmap;

4:bitmap = loadAndPrintDpi(resource, scale);

5:

6:finalView view =newView(this);

7:view.setOnClickListener(newView.OnClickListener() {//给当前veiw设置OnOnClickListener

8:@Override

9:public voidonClick(View v) {

10://Toast.makeText(NewViewTest.this,"View onClick" , Toast.LENGTH_LONG).show();

11:}

12:});

13:view.setOnTouchListener(newView.OnTouchListener() {//给当前view设置OnTouchListener

14:@Override

15:public booleanonTouch(View v, MotionEvent event) {

16:Toast.makeText(NewViewTest.this,"x="+event.getX()+" y="+event.getY() , Toast.LENGTH_LONG).show();

17:v.setBackgroundColor(Color.BLUE);

18:

19:return false;

20:}

21:});

22:finalBitmapDrawable d =newBitmapDrawable(getResources(), bitmap);

23:if(!scale)

24:d.setTargetDensity(getResources().getDisplayMetrics());

25:view.setBackgroundDrawable(d);

26:

27:view.setLayoutParams(newLinearLayout.LayoutParams(d.getIntrinsicWidth(), d

28:.getIntrinsicHeight()));

29:layout.addView(view);

30:}

31:privateView scrollWrap(View view) {

32:ScrollView scroller =newScrollView(this);

33:scroller.addView(view,newScrollView.LayoutParams(

34:ScrollView.LayoutParams.FILL_PARENT,

35:ScrollView.LayoutParams.FILL_PARENT));

36:returnscroller;

37:}

38:

39:

14. FingerPaint:手写板

14.1

1:MaskFilter mEmboss =newEmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f);//浮雕

2:

3:MaskFilter mBlur =newBlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);//模糊

4:

14.2

//触摸事件

1:public booleanonTouchEvent(MotionEvent event) {

2:floatx = event.getX();

3:floaty = event.getY();

4:

5:switch(event.getAction()) {

6:caseMotionEvent.ACTION_DOWN:

7:touch_start(x, y);

8:invalidate();

9:break;

10:caseMotionEvent.ACTION_MOVE:

11:touch_move(x, y);

12:invalidate();

13:break;

14:caseMotionEvent.ACTION_UP:

15:touch_up();

16:invalidate();

17:break;

18:}

19:return true;

20:}

21:

14.3 画路径

1:private floatmX, mY;

2:private static final floatTOUCH_TOLERANCE = 4;

3:

4:private voidtouch_start(floatx,floaty) {

5:mPath.reset();

6:mPath.moveTo(x, y);//设置起始点

7:mX = x;

8:mY = y;

9:}

10:

11:private voidtouch_move(floatx,floaty) {

12:floatdx = Math.abs(x - mX);

13:floatdy = Math.abs(y - mY);

14:if(dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {

15:mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);

16:mX = x;

17:mY = y;

18:}

19:}

20:

21:private voidtouch_up() {

22:mPath.lineTo(mX, mY);

23:// commit the path to our offscreen

24:mCanvas.drawPath(mPath, mPaint);

25:// kill this so we don't double draw

26:mPath.reset();

27:}

28:

29:

14.4此程序实现了接口implements
ColorPickerDialog.OnColorChangedListener

所以要实现方法

1:public voidcolorChanged(intcolor) {

2:mPaint.setColor(color);

3:Toast.makeText(FingerPaint.this,"colorChanged", Toast.LENGTH_LONG).show();

4:}

5:

在菜单选项中选择COLOR_MENU_ID时new ColorPickerDialog(this, this, mPaint.getColor()).show();//

1:public booleanonOptionsItemSelected(MenuItem item) {

2:mPaint.setXfermode(null);

3:mPaint.setAlpha(0xFF);

4:

5:switch(item.getItemId()) {

6:caseCOLOR_MENU_ID:

7:newColorPickerDialog(this,this, mPaint.getColor()).show();//

8:return true;

9:caseEMBOSS_MENU_ID:

10:if(mPaint.getMaskFilter() != mEmboss) {

11:mPaint.setMaskFilter(mEmboss);//设置为浮雕

12:}else{

13:mPaint.setMaskFilter(null);

14:}

15:return true;

16:caseBLUR_MENU_ID:

17:if(mPaint.getMaskFilter() != mBlur) {

18:mPaint.setMaskFilter(mBlur);

19:}else{

20:mPaint.setMaskFilter(null);

21:}

22:return true;

23:caseERASE_MENU_ID:

24:mPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.CLEAR));//设置Xfermode为擦除

25:return true;

26:caseSRCATOP_MENU_ID:

27:mPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));//此方法在VIEW上画完就清除

28:mPaint.setAlpha(0x80);

29:return true;

30:}

15. Layers:

15.1 没有第10，17行两个球边缘有锯齿

1:private static final intLAYER_FLAGS = Canvas.MATRIX_SAVE_FLAG

2:| Canvas.CLIP_SAVE_FLAG| Canvas.HAS_ALPHA_LAYER_SAVE_FLAG

3:| Canvas.FULL_COLOR_LAYER_SAVE_FLAG| Canvas.CLIP_TO_LAYER_SAVE_FLAG;

4:@Override

5:protected voidonDraw(Canvas canvas) {

6:canvas.drawColor(Color.WHITE);

7:

8:canvas.translate(10, 10);

9:

10:canvas.saveLayerAlpha(0, 0, 200, 200, 0x88,LAYER_FLAGS);

11:

12:mPaint.setColor(Color.RED);

13:canvas.drawCircle(75, 75, 75,mPaint);

14:mPaint.setColor(Color.BLUE);

15:canvas.drawCircle(125, 125, 75,mPaint);

16:

17:canvas.restore();

18:}

16. MeasureText：

Paint的样式属性：

1:mPaint=newPaint();

2:mPaint.setAntiAlias(true);

3:mPaint.setStrokeWidth(5);

4:mPaint.setStrokeCap(Paint.Cap.ROUND);//在画点时，此句有效The shape of the point is controlled by the paint's Cap type

5:mPaint.setTextSize(64);

6:mPaint.setTypeface(Typeface.create(Typeface.SERIF, Typeface.ITALIC));

画字符的方法：

1:private voidshowText(Canvas canvas, String text, Paint.Align align) {

2:// mPaint.setTextAlign(align);

3:

4:Rect bounds =newRect();

5:float[] widths =new float[text.length()];

6://获得字符串text中每个字符的像素宽存于widths中，返回字符串text的长度（有几个字符）

7:intcount =mPaint.getTextWidths(text, 0, text.length(), widths);

8://获得字符串text整个像素宽

9:floatw =mPaint.measureText(text, 0, text.length());

10://将字符串text所占矩形空间（最小，正好包起来）坐标存在bounds里

11:mPaint.getTextBounds(text, 0, text.length(), bounds);

12:

13:mPaint.setColor(0xFF88FF88);

14:canvas.drawRect(bounds,mPaint);

15:mPaint.setColor(Color.BLACK);

16:canvas.drawText(text, 0, 0,mPaint);

17://计算每个字符的刚好占的宽的点坐标

18:float[] pts =new float[2 + count * 2];

19:floatx = 0;

20:floaty = 0;

21:pts[0] = x;

22:pts[1] = y;

23:for(inti = 0; i < count; i++) {

24:x += widths[i];

25:pts[2 + i * 2] = x;

26:pts[2 + i * 2 + 1] = y;

27:}

28:mPaint.setColor(Color.RED);

29:mPaint.setStrokeWidth(0);

30:canvas.drawLine(0, 0, w, 0,mPaint);

31:mPaint.setStrokeWidth(5);

32:

33:canvas.drawPoints(pts, 0, (count + 1) << 1,mPaint);//pts Array of points to draw [x0 y0 x1 y1 x2 y2 ...]

34:}

onDraw方法:

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:canvas.drawColor(Color.WHITE);

4:

5:canvas.translate(mOriginX,mOriginY);//置换原点坐标

6:

7:showText(canvas,"Measure", Paint.Align.LEFT);

8:canvas.translate(0, 80);

9:showText(canvas,"wiggy!", Paint.Align.CENTER);

10:canvas.translate(0, 80);

11:showText(canvas,"Text", Paint.Align.RIGHT);

12:}

17 .PathEffects：画动态路径，按中间键还能变换路径（没看）

18.PathFillTypes

path为两个圆：

1:mPath=newPath();

2:mPath.addCircle(40, 40, 45, Path.Direction.CCW);

3:mPath.addCircle(80, 80, 45, Path.Direction.CCW);

DrawPath方法：

1:private voidshowPath(Canvas canvas,intx,inty, Path.FillType ft,

2:Paint paint) {

3:canvas.save();//

4:

5:canvas.translate(x, y);

6:canvas.clipRect(0, 0, 120, 120);

7:canvas.drawColor(Color.WHITE);

8:mPath.setFillType(ft);//设置填充方式

9:canvas.drawPath(mPath, paint);

10:

11:canvas.restore();

12:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:Paint paint =mPaint;

4:

5:canvas.drawColor(0xFFCCCCCC);

6:

7:canvas.translate(20, 20);

8:

9:paint.setAntiAlias(true);

10://用四种填充方式画4次path

11:showPath(canvas, 0, 0, Path.FillType.WINDING, paint);

12:showPath(canvas, 160, 0, Path.FillType.EVEN_ODD, paint);

13:showPath(canvas, 0, 160, Path.FillType.INVERSE_WINDING, paint);

14:showPath(canvas, 160, 160, Path.FillType.INVERSE_EVEN_ODD, paint);

15:}

19.Patterns: 触摸拖动时，上面的一层可以动

上层的图形（小图）

1:private staticBitmap makeBitmap2() {

2:Bitmap bm = Bitmap.createBitmap(64, 64, Bitmap.Config.ARGB_8888);

3:Canvas c =newCanvas(bm);

4:Paint p =newPaint(Paint.ANTI_ALIAS_FLAG);

5:p.setColor(Color.GREEN);

6:p.setAlpha(0xCC);// 0XFF为完全透明，0X00为完全不透明

7:c.drawCircle(32, 32, 27, p);

8:returnbm;

9:}

View的构造方法中创建mShader2：

1:publicSimlpeView(Context context) {

2:super(context);

3:setFocusable(true);

4:setFocusableInTouchMode(true);

5:

6:mFastDF=newPaintFlagsDrawFilter(Paint.FILTER_BITMAP_FLAG

7:| Paint.DITHER_FLAG, 0);// 不懂是什么意思？

8:mShader2=newBitmapShader(makeBitmap2(), Shader.TileMode.REPEAT,

9:Shader.TileMode.REPEAT);// 用张小图，拼成一个地转多块的大图

10:

11:Matrix m =newMatrix();

12:m.setRotate(30);

13:mShader2.setLocalMatrix(m);// 图mShader2设置30度的旋转

14:

15:mPaint=newPaint(Paint.FILTER_BITMAP_FLAG);

16:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:super.onDraw(canvas);

4:canvas.setDrawFilter(mDF);

5:canvas.translate(mTouchCurrX-mTouchStartX,mTouchCurrY-mTouchStartY);// 用触摸的位移作为原点，让图动起来

6:

7:mPaint.setShader(mShader2);//把整个图形作为样式

8:canvas.drawPaint(mPaint);//重要

9:}

onTouchEvent方法（控制原点坐标为触摸相对位移）：

1:@Override

2:public booleanonTouchEvent(MotionEvent event) {

3:floatx = event.getX();

4:floaty = event.getY();

5:switch(event.getAction()) {

6:caseMotionEvent.ACTION_DOWN:

7:mTouchCurrX=mTouchStartX= x;

8:mTouchCurrY=mTouchStartY= y;

9:mDF=mFastDF;

10:invalidate();

11:break;

12:caseMotionEvent.ACTION_MOVE:

13:mTouchCurrX= x;

14:mTouchCurrY= y;

15:invalidate();

16:break;

17:caseMotionEvent.ACTION_UP:

18:mDF=null;

19:invalidate();

20:break;

21:default:

22:break;

23:}

24:return true;// super.onTouchEvent(event);此处一定是true才能触摸起作用

25:}

20.Pictures：针对Picture对象的画法

新建Picture对象，从beginRecording开始记录画图命令，到endRecording，其间画的图全画在Picture里了（第2，3行）：

第5行表明可以从一个Picture对象，得到一个Drawable

1:mPicture=newPicture();//新建一个Picture对象

2:drawSomething(mPicture.beginRecording(200, 100));//在mPicture上作画。记录所有draw命令,beginRecording为开始记录

3:mPicture.endRecording();//结束记录

4:

5:mDrawable=newPictureDrawable(mPicture);//从Picture得到一个Drawable

drawSomething（）方法：在Picture上画一个圆和字符串

1:static voiddrawSomething(Canvas canvas) {

2:Paint p =newPaint(Paint.ANTI_ALIAS_FLAG);

3:

4:p.setColor(0x88FF0000);

5:canvas.drawCircle(50, 50, 40, p);

6:

7:p.setColor(Color.GREEN);

8:p.setTextSize(30);

9:canvas.drawText("Pictures", 60, 60, p);

10:}

Picture的几法画法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:canvas.drawColor(Color.WHITE);

4:

5:canvas.drawPicture(mPicture);//画Picture

6:

7:canvas.drawPicture(mPicture,newRectF(0, 100, getWidth(), 200));//stretched 拉申在这矩形里

8:

9:mDrawable.setBounds(0, 200, getWidth(), 300);

10:mDrawable.draw(canvas);

11:

12:ByteArrayOutputStream os =newByteArrayOutputStream();

13:mPicture.writeToStream(os);//Picture可以写入流中

14:InputStream is =newByteArrayInputStream(os.toByteArray());

15:canvas.translate(0, 300);

16:canvas.drawPicture(Picture.createFromStream(is));//从流中创建Picture对象

17:}

21. PolyToPoly:

先画出第一个图：

paint的属性：

1:mPaint.setStrokeWidth(4);

2:mPaint.setTextSize(40);

3:mPaint.setTextAlign(Paint.Align.CENTER);

4:

5:mFontMetrics=mPaint.getFontMetrics();//

画图方法：

1:privatePaintmPaint=newPaint(Paint.ANTI_ALIAS_FLAG);

2:privateFontMetricsmFontMetrics;

3:

4:private voiddoDraw(Canvas canvas,floatsrc[],floatdst[]) {

5:canvas.save();

6:

7:mPaint.setColor(Color.GRAY);

8:mPaint.setStyle(Paint.Style.STROKE);

9:canvas.drawRect(0, 0, 64, 64,mPaint);

10:canvas.drawLine(0, 0, 64, 64,mPaint);

11:canvas.drawLine(0, 64, 64, 0,mPaint);

12:

13:mPaint.setColor(Color.RED);

14:mPaint.setStyle(Paint.Style.FILL);

15:floatx = 64 / 2;

16:floaty = 64 / 2-(mFontMetrics.ascent+mFontMetrics.descent)/2;

17:canvas.drawText(src.length/ 2 +"", x, y,mPaint);

18:canvas.restore();

19:}

注意：如果没有mFontMetrics=mPaint.getFontMetrics();//和第16句的话，画出来的图是

在上面代码的基础上加入mMatrix.setPolyToPoly

1:private voiddoDraw(Canvas canvas,floatsrc[],floatdst[]) {

2:canvas.save();

3:

4:mMatrix.setPolyToPoly(src, 0, dst, 0, src.length>> 1);//

5:canvas.concat(mMatrix);//

6:

7:mPaint.setColor(Color.GRAY);

8:mPaint.setStyle(Paint.Style.STROKE);

9:canvas.drawRect(0, 0, 64, 64,mPaint);

10:canvas.drawLine(0, 0, 64, 64,mPaint);

11:canvas.drawLine(0, 64, 64, 0,mPaint);

12:

13:mPaint.setColor(Color.RED);

14:mPaint.setStyle(Paint.Style.FILL);

15:floatx = 64 / 2;

16:floaty = 64 / 2 - (mFontMetrics.ascent+mFontMetrics.descent) / 2;

17:canvas.drawText(src.length/ 2 +"", x, y,mPaint);

18:canvas.restore();

19:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:super.onDraw(canvas);

4:canvas.drawColor(Color.WHITE);

5:doDraw(canvas,new float[] { 0, 0,64,32 },new float[] { 32, 32,160,192 });

6:}

现在画出的图为：

可以看出在new float[] { 0, 0,64,32 },new float[] { 32, 32,160,192 }两个数组中的坐标为，（0，0）点置换到（32，32）点，（64，32）点（也就是1图的右边中间点）置换到（160，192）也就是屏幕中间X坐标

doDraw(canvas,new float[] { 0, 0,64,32 },new float[] { 32, 32,160,192 });

22. Regions

画两个空心矩形方法：加上inset线条会很细，不加是这样的加了是

1:private static voiddrawCentered(Canvas c, Rect r, Paint p) {

2:floatinset = p.getStrokeWidth() * 0.5f;

3:if(inset == 0) {// catch hairlines

4:inset = 0.5f;

5:}

6:c.drawRect(r.left+ inset, r.top+ inset, r.right- inset, r.bottom

7:- inset, p);

8:}

上面4个图的核心画法：

1:private voiddrawRgn(Canvas canvas,intcolor, String str, Region.Op op) {

2:if(str !=null) {

3:mPaint.setColor(Color.BLACK);

4:canvas.drawText(str, 80, 24,mPaint);

5:}

6:

7:Region rgn =newRegion();

8:rgn.set(mRect1);

9:rgn.op(mRect2, op);

10:

11:mPaint.setColor(color);

12:RegionIterator iter =newRegionIterator(rgn);

13:Rectr =newRect();

14:

15:canvas.translate(0, 30);

16:mPaint.setColor(color);

17:while(iter.next(r)) {

18:canvas.drawRect(r,mPaint);

19:}

20:drawOriginalRects(canvas, 0x80);

21:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:canvas.drawColor(Color.GRAY);

4:

5:canvas.save();

6:canvas.translate(80, 5);

7:drawOriginalRects(canvas, 0xFF);

8:canvas.restore();

9:

10:mPaint.setStyle(Paint.Style.FILL);

11:

12:canvas.save();

13:canvas.translate(0, 140);

14:drawRgn(canvas, Color.RED,"Union", Region.Op.UNION);

15:canvas.restore();

16:

17:canvas.save();

18:canvas.translate(0, 280);

19:drawRgn(canvas, Color.BLUE,"Xor", Region.Op.XOR);

20:canvas.restore();

21:

22:canvas.save();

23:canvas.translate(160, 140);

24:drawRgn(canvas, Color.GREEN,"Difference", Region.Op.DIFFERENCE);

25:canvas.restore();

26:

27:canvas.save();

28:canvas.translate(160, 280);

29:drawRgn(canvas, Color.WHITE,"Intersect", Region.Op.INTERSECT);

30:canvas.restore();

31:}

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上一篇：（转）DroidDraw 教程二: Table Layout

一.package com.example.android.apis.content;

1.ReadAsset:从asset目录里读出

2.ResourcesSample：在values的strings.xml里取得string,

以及在非activity里取得方法。

Resources res = context.getResources();
CharSequence cs = res.getText(R.string.styled_text);

3.StyledText:在TextView里直接setText带有styled的字符串<string name="styled_text">Plain, <b>bold</b>, <i>italic</i>, <b><i>bold-italic</i></b></string>

二.package com.example.android.apis.graphics;

1.AlphaBitmap：应用Paint p.setAntiAlias(true);//抗锯齿，如果没有调用这个方法，写上去的字不饱满，不美观，看地不太清楚

下图为p.setAntiAlias(false)效果

下图为p.setAntiAlias(true)效果

1.1 p.setAlpha(0x80);//透明度

1.2 p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));//14例中FingerPaint:手写板有这个用法

1.3 p.setTextSize(60);//设置字体大小

1.4 p.setTextAlign(Paint.Align.CENTER);//基准线

1.5 InputStream is = context.getResources().openRawResource(//从drawable里的图片转到bitmap
R.drawable.app_sample_code);
mBitmap = BitmapFactory.decodeStream(is);

1.6 mShader = new LinearGradient(0, 0, 100, 70, new int[] { Color.RED,//渐变
Color.GREEN, Color.BLUE }, null, Shader.TileMode.MIRROR);

p.setShader(mShader);

2.AnimateDrawables把一张照片动起来，类似跑马灯的效果，有三个类AnimateDrawables ，AnimateDrawable，ProxyDrawable

2.1 Drawable dr = context.getResources().getDrawable(R.drawable.beach);//获得Drawable
dr.setBounds(0, 0, dr.getIntrinsicWidth(), dr.getIntrinsicHeight());//设置图的边界，有放大缩小的作用这是设置为100，100的边界效果

2.2 Animation an = new TranslateAnimation(0, 100, 0, 200);//从0，0点到100，200移动的动画
an.setDuration(2000);//持续时间2秒
an.setRepeatCount(-1);//无限循环

2.3 public void draw(Canvas canvas) {
Drawable dr = getProxy();
if (dr != null) {
int sc = canvas.save();//
Animation anim = mAnimation;
if (anim != null) {
anim.getTransformation(AnimationUtils.currentAnimationTimeMillis()//动起来
mTransformation);//该方法根据当前间 (currentTime) 和 interpolator，计算当前的变换，在 outTransformation 中返回
canvas.concat(mTransformation.getMatrix());//对canvas应用矩阵变换
}
dr.draw(canvas);
canvas.restoreToCount(sc);
}
}

注意：canvas.save();//canvas.restoreToCount(sc);是正对出现的
假设我们将要对canvas进行了一系列的设置，例如旋转，变色等，而又不希望在操作完之后让这些设置影响到后面的绘画。
就需要在设置前先save，使用完之后再restore；带count的恢复，是指直接回复到某个状态

假设我们设置了clip去绘画一张图片的一小部分
一般这么干
canvas.save();
canvas.setclip
canvas.drawBitmap
canvas.restore();

3. Arcs：

3.1 mPaints[0] = new Paint();
mPaints[0].setAntiAlias(true);
mPaints[0].setStyle(Paint.Style.FILL);
mPaints[0].setColor(0x88FF0000);
mUseCenters[0] = false;

mPaints[1] = new Paint(mPaints[0]);
mPaints[1].setColor(0x8800FF00);
mUseCenters[1] = true;

mPaints[2] = new Paint(mPaints[0]);
mPaints[2].setStyle(Paint.Style.STROKE);
mPaints[2].setStrokeWidth(4);
mPaints[2].setColor(0x880000FF);
mUseCenters[2] = false;

3.2 canvas.drawArc(oval, mStart, mSweep, useCenter, paint);//useCenter为是否画中心。mStart起始度数，mSweep跨度

4.BitmapDecode：最下面的国旗是GIF动画

4.1 两种加载图片，再转成bitmap的方法

// now opts.outWidth and opts.outHeight are the dimension of the
// bitmap, even though bm is null

opts.inJustDecodeBounds = false; // this will request the bm
opts.inSampleSize = 4; // scaled down by 4 面试变成1/4大小
bm = BitmapFactory.decodeStream(is, null, opts);

mBitmap = bm;

// decode an image with transparency
is = context.getResources().openRawResource(R.drawable.frog);
mBitmap2 = BitmapFactory.decodeStream(is);

4.2 mBitmap2.getPixels(pixels, 0, w, 0, 0, w, h);//获得mBitmap2的像素颜色值，赋值给pixels，第三个参数为一行的像素数（矩形的宽）

mBitmap3 = Bitmap.createBitmap(pixels, 0, w, w, h,
Bitmap.Config.ARGB_8888);//用上面的pixels颜色数组创建一个Bitmap

4.3 mDrawable = context.getResources().getDrawable(R.drawable.button);
mDrawable.setBounds(150, 20, 300, 100);//设置button9的面积（只有Drawable才有这个方法）

4.4 canvas.drawBitmap(mBitmap4, 210, 170, null); //Bitmap的画法

mDrawable.draw(canvas);//Drawable的画法

4.5 is = context.getResources().openRawResource(R.drawable.animated_gif);//获得GIF动画流

mMovie = Movie.decodeStream(is);//把流转成Movie

//画Movie动画

long now = android.os.SystemClock.uptimeMillis();//当前时间
if (mMovieStart == 0) { // first time
mMovieStart = now;
}
if (mMovie != null) {
int dur = mMovie.duration();//GIF持续时间
if (dur == 0) {
dur = 1000;
}
int relTime = (int) ((now - mMovieStart) % dur);
mMovie.setTime(relTime);
mMovie.draw(canvas, getWidth() - mMovie.width(), getHeight()//画动画，参数为X,Y点
- mMovie.height());
invalidate();//刷新，不停的画
}

5. BitmapMesh：(没看)

5.1 mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.beach); //生成Bitmap

6.BitmapPixels：（没看）

7. CameraPreview：（没看）内容同SDK开发大全中的7.15例

7.1 // Hide the window title.隐藏标题
requestWindowFeature(Window.FEATURE_NO_TITLE);

8. Clipping：

8.1

//定好样式

mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(6);//画笔的宽
mPaint.setTextSize(16);
mPaint.setTextAlign(Paint.Align.RIGHT);

canvas.drawLine(0, 0, 100, 100, mPaint);//画线画的线为mPaint指定的宽度

8.2

canvas.save();
canvas.translate(160, 10);
canvas.clipRect(10, 10, 90, 90);
canvas.clipRect(30, 30, 70, 70, Region.Op.DIFFERENCE);
drawScene(canvas);
canvas.restore();

8.3

canvas.save();
canvas.translate(10, 160);
mPath.reset();
canvas.clipPath(mPath); // makes the clip empty
mPath.addCircle(50, 50, 50, Path.Direction.CCW);
canvas.clipPath(mPath, Region.Op.REPLACE);
drawScene(canvas);
canvas.restore();

9. ColorFilters：

9.1

Paint.FontMetrics fm = mPaint.getFontMetrics();//不知道是什么意思？？？？？？
float mPaintTextOffset = (fm.descent + fm.ascent) * 0.5f;

9.2

mColors = new int[] { 0, 0xCC0000FF, 0x880000FF, 0x440000FF, 0xFFCCCCFF,
0xFF8888FF, 0xFF4444FF, };

mModes = new PorterDuff.Mode[] { PorterDuff.Mode.SRC_ATOP,//过滤器的方式
PorterDuff.Mode.MULTIPLY, };
mModeIndex = 0;

filter = new PorterDuffColorFilter(mColors [i], mModes[mModeIndex]);//用mColors [i]和porter-duff mode的颜色创建一个颜色过滤

mDrawable.setColorFilter(filter);
mDrawable.draw(canvas);

10.ColorMatrixTest

private void setContrast(ColorMatrix cm, float contrast) {
float scale = contrast + 1.f;
float translate = (-.5f * scale + .5f) * 255.f;
cm.set(new float[] { scale, 0, 0, 0, translate, 0, scale, 0, 0,
translate, 0, 0, scale, 0, translate, 0, 0, 0, 1, 0 });
}

ColorMatrix cm = new ColorMatrix();

mAngle += 2;
if (mAngle > 180) {
mAngle = 0;
}

float contrast = mAngle / 180.f;

setContrast(cm, contrast);
paint.setColorFilter(new ColorMatrixColorFilter(cm));//设置颜色过滤
canvas.drawBitmap(mBitmap, x + mBitmap.getWidth() + 10, y, paint);
invalidate();

11.Compass指南针：（没看）

12.CreateBitmap：

12.1 创建颜色数组（说实话没看懂）

private static int[] createColors() {
int[] colors = new int[STRIDE * HEIGHT];
for (int y = 0; y < HEIGHT; y++) {
for (int x = 0; x < WIDTH; x++) {
int r = x * 255 / (WIDTH - 1);
int g = y * 255 / (HEIGHT - 1);
int b = 255 - Math.min(r, g);
int a = Math.max(r, g);
colors[y * STRIDE + x] = (a << 24) | (r << 16) | (g << 8) | b;
}
}
return colors;
}

12.2

private static Bitmap codec(Bitmap src, Bitmap.CompressFormat format,
int quality) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
src.compress(format, quality, os); //压缩

byte[] array = os.toByteArray();
return BitmapFactory.decodeByteArray(array, 0, array.length);
}

mJPEG[i] = codec(mBitmaps[i], Bitmap.CompressFormat.JPEG, 80);//用JPEG编码

13.DensityActivity

13.1

1:LinearLayout root =newLinearLayout(this);//设置一个线性布局root

2:root.setOrientation(LinearLayout.VERTICAL);//方向垂直

3:

4:LinearLayout layout =newLinearLayout(this);//在root布局内，又建一个layout布局

5:addBitmapDrawable(layout, R.drawable.logo120dpi,true);//以logo120dpi为View的背景，并把view加下布局

6:

7:

8:addBitmapDrawable(layout, R.drawable.logo160dpi,true);

9://addBitmapDrawable(layout, R.drawable.logo240dpi, true);

10:addLabelToRoot(root,"Prescaled bitmap in drawable");//加入一个TextView到root

11:addChildToRoot(root, layout);

12:setContentView(scrollWrap(root));

13:

14:}

15:

16:

1:private voidaddLabelToRoot(LinearLayout root, String text) {

2:TextView label =newTextView(this);

3:label.setText(text);

4:root.addView(label,newLinearLayout.LayoutParams(

5:LinearLayout.LayoutParams.FILL_PARENT,

6:LinearLayout.LayoutParams.WRAP_CONTENT));

7:}

8:

9:private voidaddChildToRoot(LinearLayout root, LinearLayout layout) {

10:root.addView(layout,newLinearLayout.LayoutParams(

11:LinearLayout.LayoutParams.FILL_PARENT,

12:LinearLayout.LayoutParams.WRAP_CONTENT));

13:}

14:

15:

16:privateBitmap loadAndPrintDpi(intid,booleanscale) {

17:Bitmap bitmap;

18:if(scale) {

19:bitmap = BitmapFactory.decodeResource(getResources(), id);

20:}else{

21:BitmapFactory.Options opts =newBitmapFactory.Options();

22:opts.inScaled =false;

23:bitmap = BitmapFactory.decodeResource(getResources(), id, opts);

24:}

25:returnbitmap;

26:}

27:

28:

//将bitmap为作View的背景，并把view加下布局

1:private voidaddBitmapDrawable(LinearLayout layout,intresource,

2:booleanscale) {

3:Bitmap bitmap;

4:bitmap = loadAndPrintDpi(resource, scale);

5:

6:finalView view =newView(this);

7:view.setOnClickListener(newView.OnClickListener() {//给当前veiw设置OnOnClickListener

8:@Override

9:public voidonClick(View v) {

10://Toast.makeText(NewViewTest.this,"View onClick" , Toast.LENGTH_LONG).show();

11:}

12:});

13:view.setOnTouchListener(newView.OnTouchListener() {//给当前view设置OnTouchListener

14:@Override

15:public booleanonTouch(View v, MotionEvent event) {

16:Toast.makeText(NewViewTest.this,"x="+event.getX()+" y="+event.getY() , Toast.LENGTH_LONG).show();

17:v.setBackgroundColor(Color.BLUE);

18:

19:return false;

20:}

21:});

22:finalBitmapDrawable d =newBitmapDrawable(getResources(), bitmap);

23:if(!scale)

24:d.setTargetDensity(getResources().getDisplayMetrics());

25:view.setBackgroundDrawable(d);

26:

27:view.setLayoutParams(newLinearLayout.LayoutParams(d.getIntrinsicWidth(), d

28:.getIntrinsicHeight()));

29:layout.addView(view);

30:}

31:privateView scrollWrap(View view) {

32:ScrollView scroller =newScrollView(this);

33:scroller.addView(view,newScrollView.LayoutParams(

34:ScrollView.LayoutParams.FILL_PARENT,

35:ScrollView.LayoutParams.FILL_PARENT));

36:returnscroller;

37:}

38:

39:

14. FingerPaint:手写板

14.1

1:MaskFilter mEmboss =newEmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f);//浮雕

2:

3:MaskFilter mBlur =newBlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);//模糊

4:

14.2

//触摸事件

1:public booleanonTouchEvent(MotionEvent event) {

2:floatx = event.getX();

3:floaty = event.getY();

4:

5:switch(event.getAction()) {

6:caseMotionEvent.ACTION_DOWN:

7:touch_start(x, y);

8:invalidate();

9:break;

10:caseMotionEvent.ACTION_MOVE:

11:touch_move(x, y);

12:invalidate();

13:break;

14:caseMotionEvent.ACTION_UP:

15:touch_up();

16:invalidate();

17:break;

18:}

19:return true;

20:}

21:

14.3 画路径

1:private floatmX, mY;

2:private static final floatTOUCH_TOLERANCE = 4;

3:

4:private voidtouch_start(floatx,floaty) {

5:mPath.reset();

6:mPath.moveTo(x, y);//设置起始点

7:mX = x;

8:mY = y;

9:}

10:

11:private voidtouch_move(floatx,floaty) {

12:floatdx = Math.abs(x - mX);

13:floatdy = Math.abs(y - mY);

14:if(dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {

15:mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);

16:mX = x;

17:mY = y;

18:}

19:}

20:

21:private voidtouch_up() {

22:mPath.lineTo(mX, mY);

23:// commit the path to our offscreen

24:mCanvas.drawPath(mPath, mPaint);

25:// kill this so we don't double draw

26:mPath.reset();

27:}

28:

29:

14.4此程序实现了接口implements
ColorPickerDialog.OnColorChangedListener

所以要实现方法

1:public voidcolorChanged(intcolor) {

2:mPaint.setColor(color);

3:Toast.makeText(FingerPaint.this,"colorChanged", Toast.LENGTH_LONG).show();

4:}

5:

在菜单选项中选择COLOR_MENU_ID时new ColorPickerDialog(this, this, mPaint.getColor()).show();//

1:public booleanonOptionsItemSelected(MenuItem item) {

2:mPaint.setXfermode(null);

3:mPaint.setAlpha(0xFF);

4:

5:switch(item.getItemId()) {

6:caseCOLOR_MENU_ID:

7:newColorPickerDialog(this,this, mPaint.getColor()).show();//

8:return true;

9:caseEMBOSS_MENU_ID:

10:if(mPaint.getMaskFilter() != mEmboss) {

11:mPaint.setMaskFilter(mEmboss);//设置为浮雕

12:}else{

13:mPaint.setMaskFilter(null);

14:}

15:return true;

16:caseBLUR_MENU_ID:

17:if(mPaint.getMaskFilter() != mBlur) {

18:mPaint.setMaskFilter(mBlur);

19:}else{

20:mPaint.setMaskFilter(null);

21:}

22:return true;

23:caseERASE_MENU_ID:

24:mPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.CLEAR));//设置Xfermode为擦除

25:return true;

26:caseSRCATOP_MENU_ID:

27:mPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));//此方法在VIEW上画完就清除

28:mPaint.setAlpha(0x80);

29:return true;

30:}

15. Layers:

15.1 没有第10，17行两个球边缘有锯齿

1:private static final intLAYER_FLAGS = Canvas.MATRIX_SAVE_FLAG

2:| Canvas.CLIP_SAVE_FLAG| Canvas.HAS_ALPHA_LAYER_SAVE_FLAG

3:| Canvas.FULL_COLOR_LAYER_SAVE_FLAG| Canvas.CLIP_TO_LAYER_SAVE_FLAG;

4:@Override

5:protected voidonDraw(Canvas canvas) {

6:canvas.drawColor(Color.WHITE);

7:

8:canvas.translate(10, 10);

9:

10:canvas.saveLayerAlpha(0, 0, 200, 200, 0x88,LAYER_FLAGS);

11:

12:mPaint.setColor(Color.RED);

13:canvas.drawCircle(75, 75, 75,mPaint);

14:mPaint.setColor(Color.BLUE);

15:canvas.drawCircle(125, 125, 75,mPaint);

16:

17:canvas.restore();

18:}

16. MeasureText：

Paint的样式属性：

1:mPaint=newPaint();

2:mPaint.setAntiAlias(true);

3:mPaint.setStrokeWidth(5);

4:mPaint.setStrokeCap(Paint.Cap.ROUND);//在画点时，此句有效The shape of the point is controlled by the paint's Cap type

5:mPaint.setTextSize(64);

6:mPaint.setTypeface(Typeface.create(Typeface.SERIF, Typeface.ITALIC));

画字符的方法：

1:private voidshowText(Canvas canvas, String text, Paint.Align align) {

2:// mPaint.setTextAlign(align);

3:

4:Rect bounds =newRect();

5:float[] widths =new float[text.length()];

6://获得字符串text中每个字符的像素宽存于widths中，返回字符串text的长度（有几个字符）

7:intcount =mPaint.getTextWidths(text, 0, text.length(), widths);

8://获得字符串text整个像素宽

9:floatw =mPaint.measureText(text, 0, text.length());

10://将字符串text所占矩形空间（最小，正好包起来）坐标存在bounds里

11:mPaint.getTextBounds(text, 0, text.length(), bounds);

12:

13:mPaint.setColor(0xFF88FF88);

14:canvas.drawRect(bounds,mPaint);

15:mPaint.setColor(Color.BLACK);

16:canvas.drawText(text, 0, 0,mPaint);

17://计算每个字符的刚好占的宽的点坐标

18:float[] pts =new float[2 + count * 2];

19:floatx = 0;

20:floaty = 0;

21:pts[0] = x;

22:pts[1] = y;

23:for(inti = 0; i < count; i++) {

24:x += widths[i];

25:pts[2 + i * 2] = x;

26:pts[2 + i * 2 + 1] = y;

27:}

28:mPaint.setColor(Color.RED);

29:mPaint.setStrokeWidth(0);

30:canvas.drawLine(0, 0, w, 0,mPaint);

31:mPaint.setStrokeWidth(5);

32:

33:canvas.drawPoints(pts, 0, (count + 1) << 1,mPaint);//pts Array of points to draw [x0 y0 x1 y1 x2 y2 ...]

34:}

onDraw方法:

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:canvas.drawColor(Color.WHITE);

4:

5:canvas.translate(mOriginX,mOriginY);//置换原点坐标

6:

7:showText(canvas,"Measure", Paint.Align.LEFT);

8:canvas.translate(0, 80);

9:showText(canvas,"wiggy!", Paint.Align.CENTER);

10:canvas.translate(0, 80);

11:showText(canvas,"Text", Paint.Align.RIGHT);

12:}

17 .PathEffects：画动态路径，按中间键还能变换路径（没看）

18.PathFillTypes

path为两个圆：

1:mPath=newPath();

2:mPath.addCircle(40, 40, 45, Path.Direction.CCW);

3:mPath.addCircle(80, 80, 45, Path.Direction.CCW);

DrawPath方法：

1:private voidshowPath(Canvas canvas,intx,inty, Path.FillType ft,

2:Paint paint) {

3:canvas.save();//

4:

5:canvas.translate(x, y);

6:canvas.clipRect(0, 0, 120, 120);

7:canvas.drawColor(Color.WHITE);

8:mPath.setFillType(ft);//设置填充方式

9:canvas.drawPath(mPath, paint);

10:

11:canvas.restore();

12:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:Paint paint =mPaint;

4:

5:canvas.drawColor(0xFFCCCCCC);

6:

7:canvas.translate(20, 20);

8:

9:paint.setAntiAlias(true);

10://用四种填充方式画4次path

11:showPath(canvas, 0, 0, Path.FillType.WINDING, paint);

12:showPath(canvas, 160, 0, Path.FillType.EVEN_ODD, paint);

13:showPath(canvas, 0, 160, Path.FillType.INVERSE_WINDING, paint);

14:showPath(canvas, 160, 160, Path.FillType.INVERSE_EVEN_ODD, paint);

15:}

19.Patterns: 触摸拖动时，上面的一层可以动

上层的图形（小图）

1:private staticBitmap makeBitmap2() {

2:Bitmap bm = Bitmap.createBitmap(64, 64, Bitmap.Config.ARGB_8888);

3:Canvas c =newCanvas(bm);

4:Paint p =newPaint(Paint.ANTI_ALIAS_FLAG);

5:p.setColor(Color.GREEN);

6:p.setAlpha(0xCC);// 0XFF为完全透明，0X00为完全不透明

7:c.drawCircle(32, 32, 27, p);

8:returnbm;

9:}

View的构造方法中创建mShader2：

1:publicSimlpeView(Context context) {

2:super(context);

3:setFocusable(true);

4:setFocusableInTouchMode(true);

5:

6:mFastDF=newPaintFlagsDrawFilter(Paint.FILTER_BITMAP_FLAG

7:| Paint.DITHER_FLAG, 0);// 不懂是什么意思？

8:mShader2=newBitmapShader(makeBitmap2(), Shader.TileMode.REPEAT,

9:Shader.TileMode.REPEAT);// 用张小图，拼成一个地转多块的大图

10:

11:Matrix m =newMatrix();

12:m.setRotate(30);

13:mShader2.setLocalMatrix(m);// 图mShader2设置30度的旋转

14:

15:mPaint=newPaint(Paint.FILTER_BITMAP_FLAG);

16:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:super.onDraw(canvas);

4:canvas.setDrawFilter(mDF);

5:canvas.translate(mTouchCurrX-mTouchStartX,mTouchCurrY-mTouchStartY);// 用触摸的位移作为原点，让图动起来

6:

7:mPaint.setShader(mShader2);//把整个图形作为样式

8:canvas.drawPaint(mPaint);//重要

9:}

onTouchEvent方法（控制原点坐标为触摸相对位移）：

1:@Override

2:public booleanonTouchEvent(MotionEvent event) {

3:floatx = event.getX();

4:floaty = event.getY();

5:switch(event.getAction()) {

6:caseMotionEvent.ACTION_DOWN:

7:mTouchCurrX=mTouchStartX= x;

8:mTouchCurrY=mTouchStartY= y;

9:mDF=mFastDF;

10:invalidate();

11:break;

12:caseMotionEvent.ACTION_MOVE:

13:mTouchCurrX= x;

14:mTouchCurrY= y;

15:invalidate();

16:break;

17:caseMotionEvent.ACTION_UP:

18:mDF=null;

19:invalidate();

20:break;

21:default:

22:break;

23:}

24:return true;// super.onTouchEvent(event);此处一定是true才能触摸起作用

25:}

20.Pictures：针对Picture对象的画法

新建Picture对象，从beginRecording开始记录画图命令，到endRecording，其间画的图全画在Picture里了（第2，3行）：

第5行表明可以从一个Picture对象，得到一个Drawable

1:mPicture=newPicture();//新建一个Picture对象

2:drawSomething(mPicture.beginRecording(200, 100));//在mPicture上作画。记录所有draw命令,beginRecording为开始记录

3:mPicture.endRecording();//结束记录

4:

5:mDrawable=newPictureDrawable(mPicture);//从Picture得到一个Drawable

drawSomething（）方法：在Picture上画一个圆和字符串

1:static voiddrawSomething(Canvas canvas) {

2:Paint p =newPaint(Paint.ANTI_ALIAS_FLAG);

3:

4:p.setColor(0x88FF0000);

5:canvas.drawCircle(50, 50, 40, p);

6:

7:p.setColor(Color.GREEN);

8:p.setTextSize(30);

9:canvas.drawText("Pictures", 60, 60, p);

10:}

Picture的几法画法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:canvas.drawColor(Color.WHITE);

4:

5:canvas.drawPicture(mPicture);//画Picture

6:

7:canvas.drawPicture(mPicture,newRectF(0, 100, getWidth(), 200));//stretched 拉申在这矩形里

8:

9:mDrawable.setBounds(0, 200, getWidth(), 300);

10:mDrawable.draw(canvas);

11:

12:ByteArrayOutputStream os =newByteArrayOutputStream();

13:mPicture.writeToStream(os);//Picture可以写入流中

14:InputStream is =newByteArrayInputStream(os.toByteArray());

15:canvas.translate(0, 300);

16:canvas.drawPicture(Picture.createFromStream(is));//从流中创建Picture对象

17:}

21. PolyToPoly:

先画出第一个图：

paint的属性：

1:mPaint.setStrokeWidth(4);

2:mPaint.setTextSize(40);

3:mPaint.setTextAlign(Paint.Align.CENTER);

4:

5:mFontMetrics=mPaint.getFontMetrics();//

画图方法：

1:privatePaintmPaint=newPaint(Paint.ANTI_ALIAS_FLAG);

2:privateFontMetricsmFontMetrics;

3:

4:private voiddoDraw(Canvas canvas,floatsrc[],floatdst[]) {

5:canvas.save();

6:

7:mPaint.setColor(Color.GRAY);

8:mPaint.setStyle(Paint.Style.STROKE);

9:canvas.drawRect(0, 0, 64, 64,mPaint);

10:canvas.drawLine(0, 0, 64, 64,mPaint);

11:canvas.drawLine(0, 64, 64, 0,mPaint);

12:

13:mPaint.setColor(Color.RED);

14:mPaint.setStyle(Paint.Style.FILL);

15:floatx = 64 / 2;

16:floaty = 64 / 2-(mFontMetrics.ascent+mFontMetrics.descent)/2;

17:canvas.drawText(src.length/ 2 +"", x, y,mPaint);

18:canvas.restore();

19:}

注意：如果没有mFontMetrics=mPaint.getFontMetrics();//和第16句的话，画出来的图是

在上面代码的基础上加入mMatrix.setPolyToPoly

1:private voiddoDraw(Canvas canvas,floatsrc[],floatdst[]) {

2:canvas.save();

3:

4:mMatrix.setPolyToPoly(src, 0, dst, 0, src.length>> 1);//

5:canvas.concat(mMatrix);//

6:

7:mPaint.setColor(Color.GRAY);

8:mPaint.setStyle(Paint.Style.STROKE);

9:canvas.drawRect(0, 0, 64, 64,mPaint);

10:canvas.drawLine(0, 0, 64, 64,mPaint);

11:canvas.drawLine(0, 64, 64, 0,mPaint);

12:

13:mPaint.setColor(Color.RED);

14:mPaint.setStyle(Paint.Style.FILL);

15:floatx = 64 / 2;

16:floaty = 64 / 2 - (mFontMetrics.ascent+mFontMetrics.descent) / 2;

17:canvas.drawText(src.length/ 2 +"", x, y,mPaint);

18:canvas.restore();

19:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:super.onDraw(canvas);

4:canvas.drawColor(Color.WHITE);

5:doDraw(canvas,new float[] { 0, 0,64,32 },new float[] { 32, 32,160,192 });

6:}

现在画出的图为：

可以看出在new float[] { 0, 0,64,32 },new float[] { 32, 32,160,192 }两个数组中的坐标为，（0，0）点置换到（32，32）点，（64，32）点（也就是1图的右边中间点）置换到（160，192）也就是屏幕中间X坐标

doDraw(canvas,new float[] { 0, 0,64,32 },new float[] { 32, 32,160,192 });

22. Regions

画两个空心矩形方法：加上inset线条会很细，不加是这样的加了是

1:private static voiddrawCentered(Canvas c, Rect r, Paint p) {

2:floatinset = p.getStrokeWidth() * 0.5f;

3:if(inset == 0) {// catch hairlines

4:inset = 0.5f;

5:}

6:c.drawRect(r.left+ inset, r.top+ inset, r.right- inset, r.bottom

7:- inset, p);

8:}

上面4个图的核心画法：

1:private voiddrawRgn(Canvas canvas,intcolor, String str, Region.Op op) {

2:if(str !=null) {

3:mPaint.setColor(Color.BLACK);

4:canvas.drawText(str, 80, 24,mPaint);

5:}

6:

7:Region rgn =newRegion();

8:rgn.set(mRect1);

9:rgn.op(mRect2, op);

10:

11:mPaint.setColor(color);

12:RegionIterator iter =newRegionIterator(rgn);

13:Rectr =newRect();

14:

15:canvas.translate(0, 30);

16:mPaint.setColor(color);

17:while(iter.next(r)) {

18:canvas.drawRect(r,mPaint);

19:}

20:drawOriginalRects(canvas, 0x80);

21:}

onDraw方法：

1:@Override

2:protected voidonDraw(Canvas canvas) {

3:canvas.drawColor(Color.GRAY);

4:

5:canvas.save();

6:canvas.translate(80, 5);

7:drawOriginalRects(canvas, 0xFF);

8:canvas.restore();

9:

10:mPaint.setStyle(Paint.Style.FILL);

11:

12:canvas.save();

13:canvas.translate(0, 140);

14:drawRgn(canvas, Color.RED,"Union", Region.Op.UNION);

15:canvas.restore();

16:

17:canvas.save();

18:canvas.translate(0, 280);

19:drawRgn(canvas, Color.BLUE,"Xor", Region.Op.XOR);

20:canvas.restore();

21:

22:canvas.save();

23:canvas.translate(160, 140);

24:drawRgn(canvas, Color.GREEN,"Difference", Region.Op.DIFFERENCE);

25:canvas.restore();

26:

27:canvas.save();

28:canvas.translate(160, 280);

29:drawRgn(canvas, Color.WHITE,"Intersect", Region.Op.INTERSECT);

30:canvas.restore();

31:}