Question

当我连续点击“捕获”按钮（没有任何中断）时，获得运行时异常我该如何解决这个问题？

如果它不可能，那我怎么处理这个例外？

btnCapture = (ImageButton) findViewById(R.id.btnCapture);
                final MediaPlayer mp = MediaPlayer.create(CameraLauncherActivity.this, R.raw.button);
                btnCapture.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {

                            // line where getting RuntimeException
                        camera.takePicture(null, null, mPicture);   

                    }
                });

日志：

02-12 14:48:41.580: E/AndroidRuntime(6997): FATAL EXCEPTION: main
02-12 14:48:41.580: E/AndroidRuntime(6997): java.lang.RuntimeException: takePicture failed
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.hardware.Camera.native_takePicture(Native Method)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.hardware.Camera.takePicture(Camera.java:1126)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.hardware.Camera.takePicture(Camera.java:1071)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at app.cam.shane.CameraLauncherActivity$3.onClick(CameraLauncherActivity.java:116)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.view.View.performClick(View.java:4223)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.view.View$PerformClick.run(View.java:17275)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.os.Handler.handleCallback(Handler.java:615)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.os.Handler.dispatchMessage(Handler.java:92)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.os.Looper.loop(Looper.java:137)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at android.app.ActivityThread.main(ActivityThread.java:4921)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at java.lang.reflect.Method.invokeNative(Native Method)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at java.lang.reflect.Method.invoke(Method.java:511)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1036)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:803)
02-12 14:48:41.580: E/AndroidRuntime(6997):     at dalvik.system.NativeStart.main(Native Method)

注意： - 与布丁相机一样，它们允许用户连续点按“捕获”按钮，但它们永远不会显示异常，如果您点击50次，它将会捕获10个或更多图像，每个图像在特定时间之后但不显示异常，就像我进入我的代码一样，以同样的方式如何处理此异常？

完整代码：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_camera);

    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

            preview=(SurfaceView)findViewById(R.id.surface);     
            previewHolder=preview.getHolder();    
            previewHolder.addCallback(surfaceCallback);    
            previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

            btnCapture = (ImageButton) findViewById(R.id.btnCapture);
            final MediaPlayer mp = MediaPlayer.create(CameraLauncherActivity.this, R.raw.button);
            btnCapture.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mp.start();
                    camera.takePicture(null, null, mPicture);                 
                }
            });


    @Override
    public void onResume() {  
        super.onResume();   
        camera=Camera.open(); 
    }  

    @Override   
    public void onPause() {  
        super.onPause();  
        if (inPreview) {  
        camera.stopPreview();   
        }   
        camera.release();   
        camera=null;   
        inPreview=false;         
    }   


    private Camera.Size getBestPreviewSize(int width, int height,
            Camera.Parameters parameters) {
            Camera.Size result=null;

            for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
                if (size.width <= width && size.height <= height) {
                    if (result == null) {
                        result=size;
                    }
                    else {
                        int resultArea=result.width * result.height;
                        int newArea=size.width * size.height;

                        if (newArea > resultArea) {
                            result=size;
                        }
                    }
                }
            }

            return(result);
        }

    private Camera.Size getSmallestPictureSize(Camera.Parameters parameters) {
        Camera.Size result=null;

        for (Camera.Size size : parameters.getSupportedPictureSizes()) {
            if (result == null) {
                result=size;
            }
            else {
                int resultArea=result.width * result.height;
                int newArea=size.width * size.height;

                if (newArea < resultArea) {
                    result=size;
                }
            }
        }

        return(result);
    }


    SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback(){

    public void surfaceCreated(SurfaceHolder holder) {     
        try {        
            camera.setPreviewDisplay(previewHolder); 
            }   catch (Throwable t) {   
                Log.e("PreviewDemo-surfaceCallback",
                        "Exception in setPreviewDisplay()", t);
                Toast.makeText(CameraLauncherActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();       
                }     
            }      

    public void surfaceChanged(SurfaceHolder holder,int format, int width,int height) {
        params = camera.getParameters();       
        params.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
        Camera.Size size = getBestPreviewSize(width, height, params);  
        Camera.Size pictureSize=getSmallestPictureSize(params);
        if (size != null && pictureSize != null) {      
            params.setPreviewSize(size.width, size.height);
            params.setPictureSize(pictureSize.width,
                    pictureSize.height);
            camera.setParameters(params);       
            camera.startPreview();       
            inPreview=true;                 

            }     
        }      

    public void surfaceDestroyed(SurfaceHolder holder) {

        }   
    };       

    PictureCallback mPicture = new PictureCallback() {
        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            pictureFile = getOutputMediaFile();
            camera.startPreview();
            if (pictureFile == null) {
                return;
            }
            try {
                FileOutputStream fos = new FileOutputStream(pictureFile);
                fos.write(data);
                fos.close();
            } catch (FileNotFoundException e) {

            } catch (IOException e) {
            }
        }
    };

    static File getOutputMediaFile() {

        /* yyyy-MM-dd'T'HH:mm:ss.SSSZ */
        timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
        .format(new Date());

        // file name
        mediaFile = new File(LoginActivity.mediaStorageDir.getPath() + File.separator
                + "IMG_" + timeStamp + ".jpg");

        return mediaFile;

    }


}

Answer 1

首先，在onPictureTaken中捕获您的异常，留下空的catch部分不是一个好习惯。然后，我会添加一个标志，以防止在保存上一张图片时调用takePicture（）。稍后在你的按钮onClick上你会检查是否可以调用takePicture（）。

声明一个标志作为您的活动的成员：
```
private boolean safeToTakePicture = false;
```
在surfaceChanged()中，只需在调用startPreview（）后将标志设置为true：
```
camera.startPreview();
safeToTakePicture = true;
```

在你的onClick()听众中检查标志并拍照，如果可以的话：

if (safeToTakePicture) {
    mp.start();
    camera.takePicture(null, null, mPicture); 
    safeToTakePicture = false;
}

在onPictureTaken()中，在保存图片后再次将标记设置为true（并添加例外打印）：

PictureCallback mPicture = new PictureCallback() {
    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        pictureFile = getOutputMediaFile();
        camera.startPreview();

        if (pictureFile == null) {
            //no path to picture, return
            safeToTakePicture = true;
            return;
        }
        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();              //<-------- show exception
        } catch (IOException e) {
            e.printStackTrace();              //<-------- show exception
        }

        //finished saving picture 
        safeToTakePicture = true;
    }
};

备注：正如文档所说，“预览必须先开始才能拍照。”，所以可能的增强功能是使用setPreviewCallback（）来注册在预览数据可用时调用的回调，以及调用onPreviewFrame时将标志设置为true。

Answer 2

我也有类似的问题。后来我发现startPreview非常重要。

在takePicutre结账第5点和第6点之前，

_camera.startPreview()非常重要 in this link

Answer 3

在我的情况下我可能有很多原因试图拍摄没有预览的照片（隐藏的照片）而我正在使用SurfaceView，所以我将其替换为SurfaceTexture

SurfaceTexture surfaceTexture = new SurfaceTexture(10);
camera.setPreviewTexture(surfaceTexture);

问题解决了...... P.S我只在6.0以上的设备上收到此错误

Answer 4

您是否忘记在相机上拨打startPreview()？

有关详细信息，请参阅here。

Answer 5

此方法可帮助您尝试解决问题。

private void safeCameraOpen(int id) {

        try {
            releaseCameraAndPreview();
            mCamera = Camera.open(id);
        } catch (Exception e) {
            Log.e(getString(R.string.app_name), "failed to open Camera");
            e.printStackTrace();
        }

    }

private void releaseCameraAndPreview() {
        if (mCamera != null) {
            mCamera.release();
            mCamera = null;
        }
    }

java.lang.RuntimeException：takePicture失败

5 个答案: