Hola, quiero crear aplicaciones simples de cropImage. Yo usocanvas y dibújelo rubtime.i dibujo el lienzo sobre la vista.así que desee recortar el área que cubre el lienzo. así que aquí me gusta esto.

Primer crearCanvas Example

public class CanvasExample extends Activity 
    {
        /** Called when the activity is first created. */

        RelativeLayout relMainOperationLayout;
        RelativeLayout relTabHeader;
        RelativeLayout relMidalLayout;
        RelativeLayout relBelowLayout;
        Context myContext;
        DrawCanvas drawCanvas;

        @Override
        public void onCreate(Bundle savedInstanceState) 
        {
            super.onCreate(savedInstanceState);
            myContext=CanvasExample.this;

            LayoutInflater layoutInflater=(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);   

            int layoutId = myContext.getResources().getIdentifier("main","layout",getPackageName());

            relMainOperationLayout = (RelativeLayout) layoutInflater.inflate(layoutId,null);

            relTabHeader=(RelativeLayout) relMainOperationLayout.findViewById(R.id.relHeadLayout);

            relMidalLayout=(RelativeLayout) relMainOperationLayout.findViewById(R.id.relmidalLayout);

            relBelowLayout=(RelativeLayout) relMainOperationLayout.findViewById(R.id.relBelowLayout);

            drawCanvas=new DrawCanvas(CanvasExample.this,myContext);
            //drawCanvas.setBackgroundColor(Color.YELLOW);
            drawCanvas.setBackgroundDrawable(CanvasExample.this.getResources().getDrawable(R.drawable.ic_launcher));
            RelativeLayout.LayoutParams drawParams=new RelativeLayout.LayoutParams(LayoutParams.FILL_PARENT,200);
            drawParams.addRule(RelativeLayout.BELOW, relTabHeader.getId());
            //relMidalLayout.addView(drawCanvas,drawParams);
            relMainOperationLayout.addView(drawCanvas,drawParams);
            setContentView(relMainOperationLayout);
        }

después de esto creo una claseDrawCanvas se extiendeView. y dibuja elCanvas correr tiempo

public class DrawCanvas extends View 

{

Context drawContext;
Activity drawActivity;
ImageView image;
Paint mPaint;
int left=0,right=0,top=0,bottom=0;
Canvas passCanvas;


public DrawCanvas(Activity activity,Context context)
{
    super(activity);
    this.drawActivity=activity;
    this.drawContext=context;


        mPaint = new Paint();

        mPaint.setDither(true);
        mPaint.setColor(Color.RED);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setStrokeWidth(3);

    this.setOnTouchListener(new View.OnTouchListener() {

        //@Override
        public boolean onTouch(View v, MotionEvent event)
        {

            switch (event.getActionMasked()) 
            {
            case MotionEvent.ACTION_DOWN:
                invalidate();
                left=(int) event.getX();
                right=left+1;
        top=(int) event.getY();

                bottom=top+1;               

                mPaint.setColor(Color.BLACK);
           onDraw(passCanvas=new Canvas());
            break;
            case   MotionEvent.ACTION_MOVE:                 
                invalidate();

                int tempX=(int) event.getX();

                if(tempX>right)
                {
                    right=right+1;

                }else
                {
                    right=right-1;
                }                   
                int tempY=(int) event.getY();

                if(tempY>bottom)
                {
                bottom=bottom+1;                
                }else
                {
                    bottom=bottom-1;        

                }
        mPaint.setColor(Color.GREEN);
                onDraw(passCanvas=new Canvas());
            break;

            case MotionEvent.ACTION_UP:
                invalidate();
                mPaint.setColor(Color.RED);
                onDraw(passCanvas=new Canvas());
                System.err.println("After Touch Up");
                Rect rect= passCanvas.getClipBounds();
                System.err.println("Save Canvas-->"+passCanvas.save());
                System.err.println("Display Rect Width==>"+rect.toString());

            break;
            default:
                break;
            }
    return true;
        }
    });     

}

@Override
protected void onDraw(Canvas canvas) 
{

    canvas.drawRect(left, top, right, bottom, mPaint);

}

}

así que ahora qué debo hacer, quiero recortar el área cubierta con un lienzo. Gracias de antemano.

cuando obtengoClipBounds Muestra un valor nulo ahora qué debo hacer.