应用程序在恢复时崩溃

时间：2015-05-22 07:09:44

标签： java android onresume

我正在创建一个简单的手电筒应用程序，但每次我离开应用程序并重新打开它时，它都会崩溃。我在代码中遗漏了什么，因为我不确定是什么，下面是崩溃时的错误。请让我知道我需要做些什么来解决这个简历问题：

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package com.example.gkvxm.materiallight;

import android.animation.ValueAnimator;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.widget.Toast;

import com.dd.CircularProgressButton;

import java.io.IOException;


public class FlashLightActivity extends Activity implements SurfaceHolder.Callback {

    private boolean isLigtOn = false;

    private Camera camera;

    @Override
    protected void onStart(){
        super.onStart();

        SurfaceView preview = (SurfaceView)findViewById(R.id.PREVIEW);
            SurfaceHolder mHolder = preview.getHolder();
        mHolder.addCallback(this);
    }

    @Override
    protected void onStop(){
        super.onStop();

        if(camera!=null){
            camera.release();
        }
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_flash_light);

        Context context = this;
        PackageManager pm = context.getPackageManager();

        if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            Toast.makeText(FlashLightActivity.this, "Your Device is not supported", Toast.LENGTH_SHORT).show();
            Log.e("err", "Device is not supported");
            return;
        }

        camera = Camera.open();
        final Camera.Parameters p = camera.getParameters();


        final CircularProgressButton circularButton1 = (CircularProgressButton) findViewById(R.id.btnWithText);
       circularButton1.setIndeterminateProgressMode(true);
        circularButton1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isLigtOn) {
                    turnOffFlash(p);
                    Toast.makeText(FlashLightActivity.this, "Lights Off!", Toast.LENGTH_SHORT).show();

                } else {
                    turnOnFlash(p);
                    Toast.makeText(FlashLightActivity.this, "Lights On!", Toast.LENGTH_SHORT).show();

                }

                if (circularButton1.getProgress() == 0) {
                    simulateSuccessProgress(circularButton1);
                } else {
                    circularButton1.setProgress(0);
                }
            }
        });
    }

    private void turnOnFlash(Camera.Parameters p){
        p.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);

        camera.setParameters(p);
        camera.startPreview();
        isLigtOn = true;
    }
    private void turnOffFlash(Camera.Parameters p){
        p.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
        camera.setParameters(p);
        camera.stopPreview();
        isLigtOn = false;
    }
    @Override
    public void surfaceChanged(SurfaceHolder holder,int format,int width,int height){

    }
    @Override
    public void surfaceCreated(SurfaceHolder holder){
        try{
            Log.i("SurfaceHolder","Setting preview");
            camera.setPreviewDisplay(holder);
        } catch (IOException e){
            e.printStackTrace();
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder){
        Log.i("SurfaceHOlder", "stopping preview");
        camera.stopPreview();
        holder = null;
    }

    private void simulateSuccessProgress(final CircularProgressButton button) {
        ValueAnimator widthAnimation = ValueAnimator.ofInt(1, 100);
        widthAnimation.setDuration(1500);
        widthAnimation.setInterpolator(new AccelerateDecelerateInterpolator());
        widthAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                Integer value = (Integer) animation.getAnimatedValue();
                button.setProgress(value);
            }
        });
        widthAnimation.start();
    }

    private void simulateErrorProgress(final CircularProgressButton button) {
        ValueAnimator widthAnimation = ValueAnimator.ofInt(1, 99);
        widthAnimation.setDuration(1500);
        widthAnimation.setInterpolator(new AccelerateDecelerateInterpolator());
        widthAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                Integer value = (Integer) animation.getAnimatedValue();
                button.setProgress(value);
                if (value == 99) {
                    button.setProgress(-1);
                }
            }
        });
        widthAnimation.start();
    }


}
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05-22 03:08:35.646  13909-13909/com.example.gkvxm.materiallight E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.gkvxm.materiallight, PID: 13909
java.lang.RuntimeException: Camera is being used after Camera.release() was called
        at android.hardware.Camera._stopPreview(Native Method)
        at android.hardware.Camera.stopPreview(Camera.java:732)
        at com.example.gkvxm.materiallight.FlashLightActivity.surfaceDestroyed(FlashLightActivity.java:129)
        at android.view.SurfaceView.updateWindow(SurfaceView.java:564)
        at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:238)
        at android.view.View.dispatchWindowVisibilityChanged(View.java:8785)
        at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1164)
        at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1164)
        at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1164)
        at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1164)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1318)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
        at android.view.Choreographer.doCallbacks(Choreographer.java:580)
        at android.view.Choreographer.doFrame(Choreographer.java:550)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5254)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

7 个答案:

答案 0 :(得分：1)

正如日志所说Camera is being used after Camera.release() was called。因此，查看onStart()您需要在onRestart()或{{1}}

中打开相机

答案 1 :(得分：1)

此异常是因为在您的活动的camera.release();方法中调用了onStop()。释放相机实例后，您将重新使用已发布的实例。 

 camera = Camera.open();

将上述行从OnCreate()移至onStart()

答案 2 :(得分：1)

您正在onPause（）中释放相机实例，这是正确的，因为文档：

  

public final void release（）

     

在API级别1中添加断开并释放Camera对象   资源。

     

完成Camera对象后，您必须立即调用它。

但你也需要在onResume（）中重新打开它，就像在onCreate中一样，因为在你恢复应用程序时并不总是会调用onCreate（）。

他们陈述here：

  

重要事项：调用release（）以释放相机以供其他人使用   应用。应用程序应立即释放相机   onPause（）（并在onResume（）中重新打开（）。

有关Android应用生命周期的详细信息，请参阅this。

祝你好运！

答案 3 :(得分：1)

camera.release();可能是onStop()。当surfaceDestroyed来电时，您使用了camera.stopPreview();

所以camera是release，而您将stopePreview。Camera is being used after Camera.release() was called多数民众赞成你@Override protected void onStop(){ super.onStop(); } 这个错误。

所以你必须坚持下去。

surfaceDestroyed

和@Override public void surfaceDestroyed(SurfaceHolder holder){ Log.i("SurfaceHOlder", "stopping preview"); camera.stopPreview(); camera.release(); holder = null; } 

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答案 4 :(得分：1)

调用Camera.release（）后正在使用相机。因此，查看活动生命周期，您需要在onStart（）或onRestart（）中打开相机。所以可能这段代码可以正常工作...... 

    package com.example.gkvxm.materiallight;

    import android.animation.ValueAnimator;
    import android.app.Activity;
    import android.content.Context;
    import android.content.pm.PackageManager;
    import android.hardware.Camera;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.KeyEvent;
    import android.view.SurfaceHolder;
    import android.view.SurfaceView;
    import android.view.View;
    import android.view.animation.AccelerateDecelerateInterpolator;
    import android.widget.Toast;

    import com.dd.CircularProgressButton;

    import java.io.IOException;


    public class FlashLightActivity extends Activity implements SurfaceHolder.Callback {

        private boolean isLigtOn = false;

        private Camera camera;

        @Override
        protected void onStart(){
            super.onStart();
             camera = Camera.open();
        final Camera.Parameters p = camera.getParameters();
            SurfaceView preview = (SurfaceView)findViewById(R.id.PREVIEW);
                SurfaceHolder mHolder = preview.getHolder();
            mHolder.addCallback(this);
        }

        @Override
        protected void onStop(){
            super.onStop();

            if(camera!=null){
                camera.release();
            }
        }
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_flash_light);

            Context context = this;
            PackageManager pm = context.getPackageManager();

            if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
                Toast.makeText(FlashLightActivity.this, "Your Device is not supported", Toast.LENGTH_SHORT).show();
                Log.e("err", "Device is not supported");
                return;
            }

            camera = Camera.open();
            final Camera.Parameters p = camera.getParameters();


            final CircularProgressButton circularButton1 = (CircularProgressButton) findViewById(R.id.btnWithText);
           circularButton1.setIndeterminateProgressMode(true);
            circularButton1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (isLigtOn) {
                        turnOffFlash(p);
                        Toast.makeText(FlashLightActivity.this, "Lights Off!", Toast.LENGTH_SHORT).show();

                    } else {
                        turnOnFlash(p);
                        Toast.makeText(FlashLightActivity.this, "Lights On!", Toast.LENGTH_SHORT).show();

                    }

                    if (circularButton1.getProgress() == 0) {
                        simulateSuccessProgress(circularButton1);
                    } else {
                        circularButton1.setProgress(0);
                    }
                }
            });
        }

        private void turnOnFlash(Camera.Parameters p){
            p.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);

            camera.setParameters(p);
            camera.startPreview();
            isLigtOn = true;
        }
        private void turnOffFlash(Camera.Parameters p){
            p.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
            camera.setParameters(p);
            camera.stopPreview();
            isLigtOn = false;
        }
        @Override
        public void surfaceChanged(SurfaceHolder holder,int format,int width,int height){

        }
        @Override
        public void surfaceCreated(SurfaceHolder holder){
            try{
                Log.i("SurfaceHolder","Setting preview");
                camera.setPreviewDisplay(holder);
            } catch (IOException e){
                e.printStackTrace();
            }
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder){
            Log.i("SurfaceHOlder", "stopping preview");
            camera.stopPreview();
            holder = null;
        }

        private void simulateSuccessProgress(final CircularProgressButton button) {
            ValueAnimator widthAnimation = ValueAnimator.ofInt(1, 100);
            widthAnimation.setDuration(1500);
            widthAnimation.setInterpolator(new AccelerateDecelerateInterpolator());
            widthAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    Integer value = (Integer) animation.getAnimatedValue();
                    button.setProgress(value);
                }
            });
            widthAnimation.start();
        }

        private void simulateErrorProgress(final CircularProgressButton button) {
            ValueAnimator widthAnimation = ValueAnimator.ofInt(1, 99);
            widthAnimation.setDuration(1500);
            widthAnimation.setInterpolator(new AccelerateDecelerateInterpolator());
            widthAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    Integer value = (Integer) animation.getAnimatedValue();
                    button.setProgress(value);
                    if (value == 99) {
                        button.setProgress(-1);
                    }
                }
            });
            widthAnimation.start();
        }


    }

答案 5 :(得分：0)

我对相机课有同样的问题。使用此行onResume（）

mCameraPreview.getHolder().removeCallback(mCameraPreview);

及其现在的工作。

答案 6 :(得分：0)

我有一个有同样问题的应用， 当我在 on create 函数中删除“on click listener”时，问题就解决了。

我认为我们永远不应该在我们的 onCreate 方法中插入任何实现函数或其他东西...

最好只使用 onCreate 来声明和实例化变量。

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