我已经实现了一个从后台线程拍摄照片的服务，但是照片永远不会在我的任何设备上拍摄…下面是代码（记录输出）：
public class PhotoCaptureService extends Service {
private static final String TAG = "PhotoCaptureService";
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
Log.d(TAG, "Starting the PhotoCaptureService");
takePhoto();
}
private void takePhoto() {
Log.d(TAG, "Preparing to take photo");
Camera camera = null;
try {
camera = Camera.open();
} catch (RuntimeException e) {
Log.e(TAG, "Camera not available", e);
return;
}
if (null == camera) {
Log.e(TAG, "Could not get camera instance");
return;
}
Log.d(TAG, "Got the camera, creating the dummy surface texture");
SurfaceTexture dummySurfaceTexture = new SurfaceTexture(0);
try {
camera.setPreviewTexture(dummySurfaceTexture);
} catch (Exception e) {
Log.e(TAG, "Could not set the surface preview texture", e);
}
Log.d(TAG, "Preview texture set, starting preview");
camera.startPreview();
Log.d(TAG, "Preview started");
camera.takePicture(null, null, new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
Log.d(TAG, "Photo taken, stopping preview");
camera.stopPreview();
Log.d(TAG, "Preview stopped, releasing camera");
camera.release();
Log.d(TAG, "Camera released");
}
});
}
日志输出：
D/PhotoCaptureService﹕ Starting the PhotoCaptureService
D/PhotoCaptureService﹕ Preparing to take photo
D/PhotoCaptureService﹕ Got the camera, creating the dummy surface texture
D/PhotoCaptureService﹕ Preview texture set, starting preview
D/PhotoCaptureService﹕ Preview started
在这一点上，不会发生其他事情，也不会调用onPictureTaken方法，也不会引发错误或异常。有人知道为什么会这样吗？我看过每一个关于stackoverflow的相机教程，但似乎什么都没用。
最佳答案
根据我的经验和我读过的资料，dummySurfaceTexture策略并不适用于所有手机。尝试添加1x1像素并在SurfaceView的SurfaceView.getHolder()回调中启动预览（通过onSurfaceCreated添加）。
有关更多信息，请参见Taking picture from camera without preview。