SurfaceView 透明和半透明

1. 透明//Transparent
2. 半透明//Translucent

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;  

public class TransParentActivity extends Activity {
    /** Called when the activity is first created. */
    class MySurfaceView extends SurfaceView implements Callback{
        float left,top;
        Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.reen);
        public MySurfaceView(Context context) {
            super(context);
            // TODO Auto-generated constructor stub
            <span style="color:#ff0000;">getHolder().setFormat(PixelFormat.TRANSPARENT);//设置为透明
            //getHolder().setFormat(PixelFormat.TRANSLUCENT);//半透明
            getHolder().addCallback(this);
            setFocusable(true);
        }  

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                int height) {
            // TODO Auto-generated method stub  

        }  

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            // TODO Auto-generated method stub
         doDraw();
        }  

        private void doDraw() {
            // TODO Auto-generated method stub
            Canvas canvas=getHolder().lockCanvas();
            canvas.drawBitmap(bitmap, left, top, null);
            getHolder().unlockCanvasAndPost(canvas);
        }  

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub  

        }  

        /* (non-Javadoc)
         * @see android.app.Activity#onTouchEvent(android.view.MotionEvent)
         */
        @Override
        public boolean onTouchEvent(MotionEvent event) {
            // TODO Auto-generated method stub
            left=event.getX();
            top=event.getY();
            doDraw();  

            return super.onTouchEvent(event);
        }
    }
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MySurfaceView(getApplicationContext()));  

    }  

} 

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="<a href="http://schemas.android.com/apk/res/android">http://schemas.android.com/apk/res/android</a>"
      package="rw.Trans"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="10" />     <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".TransParentActivity"
                  android:label="Transparent SurfaceView"
                 android:theme="@android:style/Theme.Translucent"
                  >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>     </application>
</manifest>