如何使SurfaceView具有透明背景？

Question

我有简单的布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/RelativeLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/backgroundtimer"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/TextView1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="@string/hello" />

    <com.fmech.zenclock.surface.ZenClockSurface
        android:id="@+id/zenClockSurface1"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"/>

</RelativeLayout>

并且有一个ZenClockSurface类

package com.fmech.zenclock.surface;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.PixelFormat;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class ZenClockSurface extends SurfaceView implements SurfaceHolder.Callback{

    private DrawClock drawClock;

    public ZenClockSurface(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        this.getHolder().setFormat(PixelFormat.TRANSLUCENT);
        getHolder().addCallback(this);
    }

    public ZenClockSurface(Context context) {
        super(context);
        this.getHolder().setFormat(PixelFormat.TRANSLUCENT);
        getHolder().addCallback(this);
    }

    public ZenClockSurface(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.getHolder().setFormat(PixelFormat.TRANSLUCENT);
        getHolder().addCallback(this);
    }

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

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        //this.getHolder().setFormat(PixelFormat.TRANSPARENT);
        drawClock = new DrawClock(getHolder(), getResources());
        drawClock.setRunning(true);
        drawClock.start();

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        // завершаем работу потока
        drawClock.setRunning(false);
        while (retry) {
            try {
                drawClock.join();
                retry = false;
            } catch (InterruptedException e) {
            }
        }

    }

    class DrawClock extends Thread{
        private boolean runFlag = false;
        private SurfaceHolder surfaceHolder;
        private Bitmap picture;
        private Matrix matrix;
        private long prevTime;
        private Paint painter;

        public DrawClock(SurfaceHolder surfaceHolder, Resources resources){
            this.surfaceHolder = surfaceHolder;

            this.surfaceHolder.setFormat(PixelFormat.TRANSLUCENT);
            picture = BitmapFactory.decodeResource(resources, R.drawable.ic_launcher);

            matrix = new Matrix();
            this.painter=new Paint();
            this.painter.setStyle(Paint.Style.FILL);

        }

        public void setRunning(boolean run) {
            runFlag = run;
        }

        @Override
        public void run() {
            Canvas canvas;
            while (runFlag) {

                    matrix.preRotate(1.0f, picture.getWidth() / 2, picture.getHeight() / 2);
                canvas = null;
                try {
                    //surfaceHolder.getSurface().setAlpha(0.5f);
                    canvas = surfaceHolder.lockCanvas(null);
                    synchronized (surfaceHolder) {

                        canvas.drawColor(Color.TRANSPARENT);

                        canvas.drawBitmap(picture, matrix, this.painter);
                    }
                } 
                finally {
                    if (canvas != null) {
                        surfaceHolder.unlockCanvasAndPost(canvas);
                    }
                }
            }
        }
    }
}

和活动代码

package com.fmech.zenclock.surface;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.os.Bundle;

public class ZenClockSurfaceActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        setContentView(R.layout.main);


    }
}

我想要android图片的背景颜色是透明但我得到黑色背景。

我有RelativeLayout的背景和一些图片没有透明的SurfaceView旋转Android图标。

我怎么做透明？

Answer 1

是的，我做到了我解决了问题

活动代码

package com.fmech.zenclock.surface;

import android.app.Activity;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class ZenClockSurfaceActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ZenClockSurface sfvTrack = (ZenClockSurface)findViewById(R.id.zenClockSurface1);
        sfvTrack.setZOrderOnTop(true);    // necessary
        SurfaceHolder sfhTrack = sfvTrack.getHolder();
        sfhTrack.setFormat(PixelFormat.TRANSLUCENT);

    }
}

表面代码

package com.fmech.zenclock.surface;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.PixelFormat;
import android.graphics.Region;
import android.util.AttributeSet;
import android.view.Surface.OutOfResourcesException;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class ZenClockSurface extends SurfaceView implements
        SurfaceHolder.Callback {

    private DrawClock drawClock;

    public ZenClockSurface(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        getHolder().addCallback(this);
    }

    public ZenClockSurface(Context context) {
        super(context);
        getHolder().addCallback(this);
    }

    public ZenClockSurface(Context context, AttributeSet attrs) {
        super(context, attrs);
        getHolder().addCallback(this);
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        drawClock = new DrawClock(getHolder(), getResources());
        drawClock.setRunning(true);
        drawClock.start();

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        drawClock.setRunning(false);
        while (retry) {
            try {
                drawClock.join();
                retry = false;
            } catch (InterruptedException e) {
            }
        }

    }

    class DrawClock extends Thread {
        private boolean runFlag = false;
        private SurfaceHolder surfaceHolder;
        private Bitmap picture;
        private Matrix matrix;
        private Paint painter;

        public DrawClock(SurfaceHolder surfaceHolder, Resources resources) {
            this.surfaceHolder = surfaceHolder;

            picture = BitmapFactory.decodeResource(resources,
                    R.drawable.ic_launcher);
            matrix = new Matrix();
            this.painter = new Paint();
            this.painter.setStyle(Paint.Style.FILL);
            this.painter.setAntiAlias(true);
            this.painter.setFilterBitmap(true);
        }

        public void setRunning(boolean run) {
            runFlag = run;
        }

        @Override
        public void run() {
            Canvas canvas;
            while (runFlag) {


                matrix.preRotate(1.0f, picture.getWidth() / 2,
                        picture.getHeight() / 2);
                canvas = null;
                try {
                    canvas = surfaceHolder.lockCanvas(null);
                    synchronized (surfaceHolder) {
                        canvas.drawColor(0, android.graphics.PorterDuff.Mode.CLEAR);
                        canvas.drawBitmap(picture, matrix, this.painter);
                    }
                } catch (IllegalArgumentException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }  finally {
                    if (canvas != null) {
                        surfaceHolder.unlockCanvasAndPost(canvas);
                    }
                }
            }
        }
    }
}

这是工作。

Answer 2

在API 3和4中，您不能将任何东西放在SurfaceView后面。 引用Dianne Hackborn：

表面视图实际上是在你的窗户后面，并在窗口打了一个洞让你看到它。 因此，您可以在窗口中放置内容，但窗口中的任何内容都不会出现在窗口中。

http://groups.google.com/group/android-developers/browse_thread/thread/8d88ef9bb22da574

---

从API 5开始，您可以使用setZOrderOnTop 。 诀窍是你必须在构造函数中执行它，以便在视图附加到窗口之前调用它：

public ZenClockSurface(Context context, AttributeSet attrs) {
  super(context, attrs);

  setZOrderOnTop(true);

  SurfaceHolder holder = getHolder();
  holder.setFormat(PixelFormat.TRANSLUCENT);
}