Android 使用低 RAM 设备拍照 - setPictureSize() 可以降低内存使用量吗？

Question

遵循 developper.android.com

中的文档

我写了一个简短的 Activity 从应用程序中拍照。

我有时会遇到这个错误：

02-23 17:37:06.323: E/IMemory(5003): binder=0x3c010388 transaction failed fd=-2147483647, size=0, err=-2147483646 (Unknown error: 2147483646)
02-23 17:37:06.328: E/IMemory(5003): cannot dup fd=-2147483647, size=0, err=-2147483646 (Bad file number)
02-23 17:37:06.328: E/IMemory(5003): cannot map BpMemoryHeap (binder=0x3c010388), size=0, fd=-1 (Bad file number)

你能帮我理解一下吗？
将图片大小设置为从 getPictureSizes() 方法检索到的最小值是在捕获时需要更少的内存还是稍后应用？

有关信息，这是我的活动（只是此 page 中代码示例的串联）。在该代码之前，我使用了一个带有预览和拍照功能的非常简单的代码。

public class CatchImage extends Activity  {
private boolean fgDebugLocal = true;
private String tagLocal = "CatchImage ";    

private Button btTake, btRetour;
private Intent intent;
private String refPhoto;


private String strPath = "";
private String strFileName = "";

private Context context;

private CameraPreview mPreview;
private FrameLayout preview;
private Camera cameraCatchImage;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);  
    context = getApplicationContext();
    /**
     * Set full screen
     * Used in Landscape
     */
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,   WindowManager.LayoutParams.FLAG_FULLSCREEN); 
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
    Baseline.tepvLogger.stat(tagLocal, "init ");

    setContentView(R.layout.camera);

    /**
     * get the id of picture
     */
    intent = getIntent();
    refPhoto = intent.getStringExtra("refPhoto");
    strPath = intent.getStringExtra("strSdInternalPath");
    StringBuilder sb = new StringBuilder();
    sb.append(strPath);
    sb.append(File.separatorChar);
    sb.append(Params.PATH_REP_PHOTO);
    sb.append(File.separatorChar);
    sb.append(Params.PHOTO_FILE_NAME);
    sb.append(refPhoto);
    sb.append(Params.PHOTO_FILE_EXT_JPG);
    strFileName = sb.toString();

    if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "strFileName = " + strFileName);};

    btTake = (Button) findViewById(R.id.btStatCatchPictureTake);
    btRetour = (Button) findViewById(R.id.btStatCatchPictureRetour);

    btTake.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "btTake");};
            mPreview.mCamera.takePicture(shutterCallback, rawCallback, jpegCallback);
        }
    });


    btRetour.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "btRetour ");};

            Intent intent = new Intent(CatchImage.this, StationnementPhoto.class);
            startActivity(intent);
            finish();

        }
    });

}

@Override
public void onResume() {
    super.onResume();
    if (!checkCameraHardware(context)) {
        afficheAlertDlg(getResources().getString(R.string.dlg_titre_alert), getResources().getString(R.string.catch_image_no_camera), getResources().getDrawable(R.drawable.ic_alert));
    } else {
        if (Camera.getNumberOfCameras()>1) {
            new TePVException(this.getClass().getName(), "checkCameraHardware", "More than one camera detected");
        }

        if (safeCameraOpen(0)) {
            if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "safeCameraOpen(0) true : creating preview");};
            btTake.setEnabled(true);
            btTake.setBackgroundResource(R.drawable.bt_border_selector);

            mPreview = new CameraPreview(context, cameraCatchImage);
            preview = (FrameLayout) findViewById(R.id.flStatCatchPreview);
            preview.addView(mPreview);

        } else { 
            btTake.setEnabled(false);
            btTake.setBackgroundResource(R.drawable.bt_border_disable);
        }
    }


}

@Override
public void onPause() {
    super.onPause();
    releaseCameraAndPreview();              // release the camera immediately on pause event
}

private boolean safeCameraOpen(int id) {
    boolean qOpened = false;

    try {
        releaseCameraAndPreview();
        cameraCatchImage = Camera.open(id);
        qOpened = (cameraCatchImage != null);
    } catch (Exception e) {
        if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "failed to open Camera");};
        e.printStackTrace();
    }

    return qOpened;    
}

private void releaseCameraAndPreview() {
    if (mPreview!=null) mPreview.setCamera(null);
    if (cameraCatchImage != null) {
        cameraCatchImage.release();
        cameraCatchImage = null;
    }
}

/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
    if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
        // this device has a camera
        return true;
    } else {
        // no camera on this device
        return false;
    }
}


ShutterCallback shutterCallback = new ShutterCallback() {
    public void onShutter() {
        if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "shutterCallback ");};
    }
};

/** Handles data for raw picture */
PictureCallback rawCallback = new PictureCallback() {
    public void onPictureTaken(byte[] data, Camera camera) {
        if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "rawCallback ");};
    }
};

private PictureCallback jpegCallback = new PictureCallback() {

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "jpegCallback ");};
        FileOutputStream outStream = null;
        try {
            //String strFileNameComplet = strPath + File.separatorChar + strFileName + refPhoto + Params.PHOTO_FILE_EXT_JPG;
            if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "strFileName = " + strFileName);};
            outStream = new FileOutputStream(strFileName);
            outStream.write(data);
            outStream.close();

            File fileVerif = new File(strFileName);
            if (fileVerif.exists()){
                if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "Photo stockée ");};
                Intent intent = new Intent(CatchImage.this, StationnementPhoto.class);
                startActivity(intent);
                finish();
            }else {
                new TePVException("CatchImage", "PictureCallback", "Pb stockage image  = " + strFileName);
                Toast.makeText(context, "Erreur enregistrement de la photo, essayez à nouveau", Toast.LENGTH_LONG).show();
            }
        } catch (FileNotFoundException e) {
            new TePVException("CatchImage", "PictureCallback", "FileNotFoundException = " + e.getMessage());
        } catch (IOException e) {
            new TePVException("CatchImage", "PictureCallback", "IOException = " + e.getMessage());
        } finally {

        }
    }
};

/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mCamera = camera;

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void setCamera(Camera object) {
        mCamera = object;
    }

    public Camera getCamera() {
        return mCamera;
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the preview.
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            if (Params.tagFgDebug && fgDebugLocal){Log.d(tagLocal, "Error setting camera preview: " + e.getMessage());}
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // empty. Take care of releasing the Camera preview in your activity.
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.

        if (mHolder.getSurface() == null){
          // preview surface does not exist
          return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e){
          // ignore: tried to stop a non-existent preview
        }

        // set preview size and make any resize, rotate or
        // reformatting changes here

        // start preview with new settings
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e){
            if (Params.tagFgDebug && fgDebugLocal){Log.d(tagLocal, "Error starting camera preview: " + e.getMessage());}
        }
    }
}

编辑：我看到了 this question 但我已经将图像保存为文件。

Answer 1

我找到了解决方案：

我们停止使用 Camera camera.takePicture()，只使用预览对象。基于用于照片显示的@CommonsWare 代码和基于斑马线精明解决方案的想法。

想法：

btTake.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            if (Params.tagFgDebug && fgDebugLocal){Log.i(Params.tagGen, tagLocal + "btTake");};
            if (inPreview) {
                camera.setOneShotPreviewCallback(previewCallback);
                inPreview=false;
            }
        }
});

预览代码：

final class PreviewCallback implements Camera.PreviewCallback {

    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
        Log.i( tagLocal , "onPreviewFrame ");
        File photo= new File(strFileName);

        if (photo.exists()) {
            photo.delete();
        }


        try { 
            Camera.Parameters parameters = camera.getParameters(); 
            Size size = parameters.getPreviewSize(); 
            YuvImage image = new YuvImage(data, parameters.getPreviewFormat(), 
                    size.width, size.height, null); 
            FileOutputStream filecon = new FileOutputStream(photo); 
            image.compressToJpeg(new Rect(0, 0, image.getWidth(), image.getHeight()), 90, filecon); 
        } catch (FileNotFoundException e) { 
            Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_SHORT).show(); 
        } 


        /**
         * Restart :
         */
        File fileVerif = new File(strFileName);
        if (fileVerif.exists() && fileVerif.length()!=0) {
            if (Params.tagFgDebug && fgDebugLocal){Log.i(tagLocal , "Photo stockée file lenght = "+ fileVerif.length());};
            Intent intent = new Intent(CatchImageCommonsWare.this, Photo.class);
            startActivity(intent);
            finish();
        } else {
            new Exception("CatchImageCommonsWare", "PreviewCallback", "Pb stockage image  = " + strFileName);
            Toast.makeText(context, "Erreur enregistrement de la photo, essayez à nouveau", Toast.LENGTH_LONG).show();
        }

    }

}

Android 使用低 RAM 设备拍照 - setPictureSize() 可以降低内存使用量吗？

Android take picture with low RAM device - Can setPictureSize() lower the memory usage?

android

memory

android-camera