图形与动画在Android中的实现

public class MyView extends View{
	Bitmap myBitmap;
	Paint paint;
	public MyView(Context context, AttributeSet attrs) {
		super(context, attrs);
		this.initBitmap();
	}
	public void initBitmap(){
		paint = new Paint();
		myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.img);
		
	}
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		paint.setAntiAlias(true);
		paint.setColor(Color.WHITE);
		paint.setTextSize(15);
		canvas.drawBitmap(myBitmap, 10,  10, paint);
		
		//Saves the current matrix and clip onto a private stack. 
		//Subsequent calls to translate,scale,rotate,skew,concat or clipRect,clipPath 
		//will all operate as usual, but when the balancing call to restore() is made, 
		//those calls will be forgotten, and the settings that existed before the save() will be reinstated(恢复).
		//Returns:
		//The value to pass to restoreToCount() to balance this save()
		int i = canvas.save();  
		System.out.println("current count -- > " + i);
		
		Matrix m1 = new Matrix();
		m1.setTranslate(500, 10);
		Matrix m2 = new Matrix();
		m2.setRotate(15);
		Matrix m3 = new Matrix();
		m3.setConcat(m1, m2);
		m1.setScale(0.8f, 0.8f);
		m2.setConcat(m3, m1);
		canvas.drawBitmap(myBitmap, m2, paint);
		
		//This call balances a previous call to save(), and is used to 
		//remove all modifications to the matrix/clip state since the last save call. 
		//It is an error to call restore() more times than save() was called.
		canvas.restore();
		int j = canvas.save();
		System.out.println("current count -- > " + j);
		paint.setAlpha(180);
		m1.setTranslate(200, 100);
		m2.setScale(1.3f, 1.3f);
		m2.setConcat(m1, m2);
		canvas.drawBitmap(myBitmap, m3, paint);
		
		//Restores the paint to its default settings. 
		paint.reset();
		canvas.restore();
		paint.setTextSize(40);
		paint.setColor(Color.BLUE);
		canvas.drawText("图片的宽度:" + myBitmap.getWidth(), 150, 220, paint);
		canvas.drawText("图片的高度:" + myBitmap.getHeight(), 150, 300, paint);
		paint.reset();
		
	}

}

效果图：