android实现图片按任意路径截取

使用 android提供的Path实現图片的截取

重写View的onTouchEvent方法和onDraw方法,onTouchEvent负责实现截取路径的构件,onDraw进行刷新页面,重写View类的代码如下 :

public class MyView extends View {private Drawable mDrawable;private Path mPath;private float mX = -1;private float mY = -1;private float mPastX;private float mPastY;public MyView(Context context) {super(context);// TODO Auto-generated constructor stubmPath = new Path();}public void setDrawable(Drawable pDrawable){mDrawable = pDrawable;}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas);Log.i("xiao", "onDraw");mDrawable.setBounds(0, 0, getWidth(), getHeight());Rect lRect = mDrawable.getBounds();Log.i("xiao", "lRect.left =  " + lRect.left + " top = " + lRect.top + " right = " + lRect.right + " bottom = " + lRect.bottom);if(!mPath.isEmpty()){Log.i("xiao", "!mPath.isEmpty()");canvas.clipPath(mPath);//mDrawable.draw(canvas);}mDrawable.draw(canvas);}@Overridepublic boolean onTouchEvent(MotionEvent event) {// TODO Auto-generated method stubLog.i("xiao", "onTouchEvent");int lAction = event.getAction();if(mX != -1){mPastX = mX;mPastY = mY;}mX = event.getX();mY = event.getY();switch(lAction){case MotionEvent.ACTION_DOWN:mPath.reset();mPath.moveTo(mX, mY);break;case MotionEvent.ACTION_MOVE:mPath.quadTo(mPastX, mPastY, (mX + mPastX) / 2, (mY + mPastY) / 2);break;case MotionEvent.ACTION_UP:mPath.lineTo(mX, mY);mX = -1;mY = -1;invalidate();break;default:break;}return true;}}

Activity主要负责获取和设置Drawable和设置布局,代码如下:

private MyView mView;     @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);                mView = new MyView(this);        mView.setDrawable(this.getResources().getDrawable(R.drawable.test1));        this.setContentView(mView);    }

未截取时效果:

画一个路径截取效果图:

附件地址:http://download.csdn.net/detail/xiaoxiaobian3310903/4436969

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