android - 如何在 android 中为 Drawpanel 设置背景？

Question

我正在使用 SurfaceView 在屏幕上绘制路径。如果我没有为 drawPanel 设置任何背景，一切正常；如果我为 SurfaceView 设置背景，则绘图不起作用。我需要一些彩色屏幕来绘图。

提前致谢。

下面是我的代码：

package com.example.draw;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.view.WindowManager;
import android.widget.FrameLayout;
public class MainActivity extends Activity implements OnTouchListener 
{
DrawPanel dp;
    private ArrayList<Path> pointsToDraw = new ArrayList<Path>();
    private Paint mPaint;
    Path path;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        dp = new DrawPanel(this);
        dp.setBackgroundColor(R.drawable.imge);
        dp.setOnTouchListener(this);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
        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(30);
        FrameLayout fl = new FrameLayout(this);
        fl.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
       //fl.setBackgroundResource(R.drawable.imge);
        fl.addView(dp);
        setContentView(fl);
    }


    @Override
    protected void onPause() 
    {
        // TODO Auto-generated method stub
        super.onPause();
        dp.pause();
    }
    @Override
    protected void onResume() 
    {
        // TODO Auto-generated method stub
        super.onResume();
        dp.resume();
    }

    public boolean onTouch(View v, MotionEvent me) 
    {
        // TODO Auto-generated method stub
                synchronized(pointsToDraw)
                {
        if(me.getAction() == MotionEvent.ACTION_DOWN)
        {
            path = new Path();
            path.moveTo(me.getX(), me.getY());
            //path.lineTo(me.getX(), me.getY());
            pointsToDraw.add(path);
        }
      else if(me.getAction() == MotionEvent.ACTION_MOVE)  
       {
            path.lineTo(me.getX(), me.getY());
        }else if(me.getAction() == MotionEvent.ACTION_UP)
        {
            //path.lineTo(me.getX(), me.getY());
        }
        }
        return true;
    }
    public class DrawPanel extends SurfaceView implements Runnable
    {
Thread t = null;
        SurfaceHolder holder;
        boolean isItOk = false ;

        public DrawPanel(Context context) 
        {
            super(context);
            // TODO Auto-generated constructor stub
            holder = getHolder();
        }

        public void run() 
        {
            // TODO Auto-generated method stub
            while( isItOk == true)
             {

                if(!holder.getSurface().isValid())
                {
                    continue;
                }

                Canvas c = holder.lockCanvas();
                c.drawARGB(255, 0, 0, 0);
                onDraw(c);
                holder.unlockCanvasAndPost(c);
            }
        }

        @Override
        protected void onDraw(Canvas canvas) 
        {
            // TODO Auto-generated method stub
            super.onDraw(canvas);
                        synchronized(pointsToDraw)
                        {
            for (Path path : pointsToDraw)
            {
                canvas.drawPath(path, mPaint);
            }
                        }
        }

        public void pause()
        {
            isItOk = false;
            while(true)
            {
                try
                {
                    t.join();
                }
               catch(InterruptedException e)
               {
                    e.printStackTrace();
                }
                break;
            }
            t = null;
        }

        public void resume()
        {
            isItOk = true;
            t = new Thread(this);
            t.start();

        }
    }
}