android實現圖片按任意路徑截取

使用 android提供的Path實現圖片的截取

重寫View的onTouchEvent方法和onDraw方法,onTouchEvent負責實現截取路徑的構件,onDraw進行刷新頁面,重寫View類的代碼如下 :

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 stub
		mPath = new Path();
	}

	public void setDrawable(Drawable pDrawable){
		mDrawable = pDrawable;
	}

	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		super.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);
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// TODO Auto-generated method stub
		Log.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主要負責獲取和設置Drawable和設置佈局,代碼如下:

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);
    }

未截取時效果:

畫一個路徑截取效果圖:

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