Android Surfaceview线程和内存泄漏

Question

我在android中创建了一个游戏，我注意到游戏有内存泄漏。我设法将内存泄漏隔离到一个较小的应用程序，以便我可以看到很好的尝试和解决，如何解决它。

应用程序对其视图使用了一个surfaceview，并附加了一个线程，以便对屏幕进行所有绘制。当我开始一个新活动并关闭我当前正在使用的活动时，会发生内存泄漏。当我在我的测试应用程序上执行内存转储时，我可以看到这一点，因为它只是打开并关闭一个活动（活动a - ＆gt;活动b - ＆gt;活动a）。我有点想法如何解决这个问题，因为我试图将我创建的所有引用归零（在线程内），iv尝试在我销毁视图时从surfaceview中删除回调，并且在活动中，它似乎没有任何区别。

MemoryLeakActivity.java

package memory.leak;

import memory.leak.view.MemoryLeak;
import android.app.Activity;
import android.os.Bundle;

public class MemoryLeakActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MemoryLeak(this));
    }
}

MemoryLeakViewThread.java

package memory.leak.thread;

import memory.leak.view.MemoryLeak;
import android.view.SurfaceHolder;
import android.graphics.Canvas;


public class MemoryLeakViewThread extends Thread {
    private MemoryLeak view;
    private boolean run =false;

    public MemoryLeakViewThread(MemoryLeak view) {
        this.view =view;
    }

    public void setRunning(boolean run) {
        this.run =run;
    }

    @Override
    public void run() {
        Canvas canvas =null;
        SurfaceHolder holder =this.view.getHolder();
        while(this.run) {
            canvas =holder.lockCanvas();
            if(canvas !=null) {
                this.view.onDraw(canvas);
                holder.unlockCanvasAndPost(canvas);
            }
        }
        holder =null;
        this.view =null;
    }
}

MemoryLeak.java

package memory.leak.view;

import memory.leak.TestActivity;
import memory.leak.thread.MemoryLeakViewThread;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Canvas;
import android.graphics.Color;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.GestureDetector.OnGestureListener;


public class MemoryLeak extends SurfaceView implements SurfaceHolder.Callback, OnGestureListener {
    private GestureDetector gesture;
    private MemoryLeakViewThread vThread;
    private Context context;

    public MemoryLeak(Context context) {
        super(context);

        this.getHolder().addCallback(this);
        this.vThread =new MemoryLeakViewThread(this);

        this.gesture =new GestureDetector(this);
        this.context =context;
    }

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

    public void surfaceCreated(SurfaceHolder holder) {
        if(!this.vThread.isAlive()) {
            this.vThread =new MemoryLeakViewThread(this);
            this.vThread.setRunning(true);
            this.vThread.start();
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;

        if(this.vThread.isAlive()) {
            this.vThread.setRunning(false);
            while(retry) {
                try {
                    this.vThread.join();
                    retry =false;
                } catch(Exception ee) {}
            }
        }

        this.vThread =null;
        this.context =null;
    }

     public boolean onTouchEvent(MotionEvent event) {
         return this.gesture.onTouchEvent(event);
     }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    }

    @Override
    public void onDraw(Canvas canvas) {
        canvas.drawColor(Color.WHITE);
    }   

    @Override
    public boolean onDown(MotionEvent e) {
        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {}

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {}

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        Intent helpScreenIntent =new Intent(this.context, TestActivity.class);
        this.context.startActivity(helpScreenIntent);

        if (this.context instanceof Activity)
            ((Activity) this.context).finish();

        return true;
    }
}

TestActivity.java

package memory.leak;

import memory.leak.view.Test;
import android.app.Activity;
import android.os.Bundle;

public class TestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new Test(this));
    }
}

TestViewThread.java

package memory.leak.thread;

import memory.leak.view.Test;
import android.view.SurfaceHolder;
import android.graphics.Canvas;


public class TestViewThread extends Thread {
    private Test panel;
    private boolean run =false;

    public TestViewThread(Test panel) {
        this.panel =panel;
    }

    public void setRunning(boolean run) {
        this.run =run;
    }

    @Override
    public void run() {
        Canvas canvas =null;
        SurfaceHolder holder =this.panel.getHolder();
        while(this.run) {
            canvas =holder.lockCanvas();
            if(canvas !=null) {
                this.panel.onDraw(canvas);
                holder.unlockCanvasAndPost(canvas);
            }
        }
        holder =null;
        this.panel =null;
    }
}

Test.java

package memory.leak.view;

import memory.leak.MemoryLeakActivity;
import memory.leak.thread.TestViewThread;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Canvas;
import android.graphics.Color;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.GestureDetector.OnGestureListener;


public class Test extends SurfaceView implements SurfaceHolder.Callback, OnGestureListener {
    private GestureDetector gesture;
    private TestViewThread vThread;
    private Context context;

    public Test(Context context) {
        super(context);

        this.getHolder().addCallback(this);
        this.vThread =new TestViewThread(this);

        this.gesture =new GestureDetector(this);
        this.context =context;
    }

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

    public void surfaceCreated(SurfaceHolder holder) {
        if(!this.vThread.isAlive()) {
            this.vThread =new TestViewThread(this);
            this.vThread.setRunning(true);
            this.vThread.start();
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;

        if(this.vThread.isAlive()) {
            this.vThread.setRunning(false);
            while(retry) {
                try {
                    this.vThread.join();
                    retry =false;
                } catch(Exception ee) {}
            }
        }

        this.vThread =null;
        this.context =null;
    }

     public boolean onTouchEvent(MotionEvent event) {
         return this.gesture.onTouchEvent(event);
     }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    }

    @Override
    public void onDraw(Canvas canvas) {
        canvas.drawColor(Color.RED);
    }   

    @Override
    public boolean onDown(MotionEvent e) {
        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {}

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {}

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        Intent helpScreenIntent =new Intent(this.context, MemoryLeakActivity.class);
        this.context.startActivity(helpScreenIntent);

        if (this.context instanceof Activity)
            ((Activity) this.context).finish();

        return true;
    }
}

- Edit-- 我将视图类更改为其surfaceDestroyed（SurfaceHolder持有者），以便在线程被告知停止时，它将设置线程必须为null的视图。我所做的改变是

public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;

        if(this.vThread.isAlive()) {
            this.vThread.setRunning(false);
            while(retry) {
                try {
                    this.vThread.join();
                    retry =false;
                } catch(Exception ee) {}
            }
            this.vThread.setRunning(false, null);
        }

        this.vThread =null;
        this.context =null;
        this.gesture =null;
    }

您还需要将surfaceCreated（SurfaceHolder holder）方法更改为

public void surfaceCreated(SurfaceHolder holder) {
        if(!this.vThread.isAlive()) {
            this.vThread =new MemoryLeakViewThread();
            this.vThread.setRunning(true, this);
            this.vThread.start();
        }
    }

然后在线程类上我们需要更改以下

public MemoryLeakViewThread() {
    }

    public void setRunning(boolean run) {
        this.run =run;
    }

    public void setRunning(boolean run, MemoryLeak view) {
        this.run =run;
        this.view =view;
    }

通过这样做似乎解决了问题，现在唯一的问题是线程似乎留在内存中，由于线程类和线程组。但我认为这可能是由于调试器。

Answer 1

在onSurfaceCreated中创建新的Thread时，不应该在构造函数中创建新的Thread。将您的代码与我的示例进行比较：How can I use the animation framework inside the canvas?

Answer 2

正如你在这里看到的那样：

http://developer.android.com/resources/articles/avoiding-memory-leaks.html

在Android中启动内存泄漏的最简单方法是将视图的构造函数传递给整个活动而不是应用程序上下文。您是否尝试更改此行：

setContentView(new MemoryLeak(this));

进入这一个：

setContentView(new MemoryLeak(Context.getApplicationContext()));

希望它有所帮助。