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我开发了一个应用程序，可以在不向用户预览照片的情况下拍摄照片。我的问题是在执行 OnPictureTaken 方法之前，有时 GC 会清理由方法 Camera.takePicture() 创建的对象。因此，当它发生时，应用程序无法保存该照片。

这是拍摄照片的班级：

public class MyCamera implements Camera.PictureCallback {

private Camera mCamera;
private Context context;

public MyCamera(Context c_) {
    Log.d(TAG, "On constructor");   
    context = c_;

    if (Camera.getNumberOfCameras() >= 2) {
        mCamera = Camera.open(CameraInfo.CAMERA_FACING_FRONT);
    } else {
        mCamera = Camera.open(CameraInfo.CAMERA_FACING_BACK);
    }
}

public void takePicture() {
    try {

        Log.d(TAG, "On take picture");  

        mCamera.setPreviewTexture(new SurfaceTexture(0));
        mCamera.startPreview();
        Thread.sleep(1000);
        Log.d(TAG, "About to take");    
        mCamera.takePicture(null, null, null, this);
        Log.d(TAG, "Took it");  

    } catch (IOException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
 }

@Override
public void onPictureTaken(byte[] data, Camera camera) {

    Log.d(TAG, "onPictureTaken");       
    File pictureFile = getOutputMediaFile(1);

    if (pictureFile == null) {
        Log.d(TAG, "Error creating picture file");
        return;
    }

    try {
        FileOutputStream fos = new FileOutputStream(pictureFile);
        fos.write(data);
        fos.close();

    } catch (Exception e) {
        Log.d(TAG, "Error writing picture");
        e.printStackTrace();
    }
    finally {
        mCamera.release();

    }
}

我尝试将回调更改为全局变量或将其用作我的类的实现，但是它们都没有顺利运行。

这是logCat：

06-08 15:46:48.554: D/MyAppService(1248): Capture camera this time
06-08 15:46:48.554: D/MyCamera(1248): On constructor
06-08 15:46:48.844: D/MyCamera(1248): On take picture
06-08 15:46:49.884: D/MyCamera(1248): About to take
06-08 15:46:49.884: D/MyCamera(1248): Took it
06-08 15:46:51.844: D/MyCamera(1248): onPictureTaken
06-08 15:46:51.854: D/DataReceive(1248): handling data
06-08 15:46:51.854: E/DataReceive(1248): Data handled
06-08 15:48:12.144: D/dalvikvm(1248): GC_FOR_ALLOC freed 479K, 3% free 17161K/17676K, paused 41ms, total 42ms
06-08 15:48:48.164: D/dalvikvm(1248): GC_EXPLICIT freed 104K, 3% free 17165K/17676K, paused 9ms+2ms, total 46ms
06-08 15:48:48.604: D/MyAppService(1248): Capture camera this time
06-08 15:48:48.604: D/MyCamera(1248): On constructor
06-08 15:48:48.884: D/MyCamera(1248): On take picture
06-08 15:48:49.914: D/MyCamera(1248): About to take
06-08 15:48:49.914: D/MyCamera(1248): Took it
06-08 15:48:51.884: D/dalvikvm(1248): GC_FOR_ALLOC freed 8K, 3% free 17163K/17676K, paused 16ms, total 16ms
06-08 15:48:52.634: I/dalvikvm-heap(1248): Grow heap (frag case) to 17.046MB for 266152-byte allocation
06-08 15:48:52.644: D/dalvikvm(1248): GC_FOR_ALLOC freed <1K, 3% free 17423K/17936K, paused 10ms, total 10ms
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1 回答 1

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我发现问题出在我的方法（takePicture）上，它在调用 onPictureTaken 之前就被关闭了。我解决了将延迟放入 takePhoto 方法的问题。

于 2015-06-15T20:25:15.093 回答