我有一个应用程序，我已拍照，然后它应该使用意图将图片中的数据发送到另一个活动。
我试图在jpegCallback内调用intent，但问题是我还需要在调用intent之前通过预览类释放相机。但是，我无法从回调内部获取原始预览对象，因此我需要一种从回调内部调用MainActivity.doPictureResults()的方法。或者我需要一种方法让一个监听器在所有图片回调完成后触发。
这是我的MainActivity类，它在Preview变量中包含mPreview类的实例。 jpegCallback位于底部，我想从内部调用doPictureResults，或者在该功能完成后设置另一个回调。
public class MainActivity extends Activity {
private final String TAG = "MainActivity";
private Preview mPreview;
Camera mCamera;
int numberOfCameras;
int cameraCurrentlyLocked;
//The first rear facing camera
int defaultCameraId;
/**
* Constructor
* @param savedInstanceState
*/
@Override
protected void onCreate(Bundle savedInstanceState) {Log.e(TAG, "onCreate");
super.onCreate(savedInstanceState);
//Hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
//Create a RelativeLayout container that will hold a SurfaceView,
//and set it as the content of our activity.
this.mPreview = new Preview(this);
setContentView(this.mPreview);
//Find the total number of cameras available
this.numberOfCameras = Camera.getNumberOfCameras();
//Find the ID of the default camera
CameraInfo cameraInfo = new CameraInfo();
for(int i = 0; i < this.numberOfCameras; i++) {
Camera.getCameraInfo(i, cameraInfo);
if(cameraInfo.facing == CameraInfo.CAMERA_FACING_BACK) {
this.defaultCameraId = i;
}
}
}
@Override
protected void onResume() {Log.e(TAG, "onResume");
super.onResume();
//Open the default i.e. the first rear facing camera.
this.mCamera = Camera.open();
this.cameraCurrentlyLocked = this.defaultCameraId;
this.mPreview.setCamera(mCamera);
}
@Override
protected void onPause() {Log.e(TAG, "onPause");
super.onPause();
//Because the Camera object is a shared resource, it's very
//Important to release it when the activity is paused.
this.mPreview.releaseCamera();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
//Inflate our menu which can gather user input for switching camera
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.camera_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
//Handle item selection
switch (item.getItemId()) {
case R.id.switchCam:
//Check for availability of multiple cameras
if(this.numberOfCameras == 1) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(this.getString(R.string.camera_alert)).setNeutralButton("Close", null);
AlertDialog alert = builder.create();
alert.show();
return true;
}
//OK, we have multiple cameras.
//Release this camera -> cameraCurrentlyLocked
this.mPreview.releaseCamera();
//Acquire the next camera and request Preview to reconfigure parameters.
this.mCamera = Camera.open((this.cameraCurrentlyLocked + 1) % this.numberOfCameras);
this.cameraCurrentlyLocked = (this.cameraCurrentlyLocked + 1) % this.numberOfCameras;
this.mPreview.switchCamera(mCamera);
//Start the preview
this.mCamera.startPreview();
return true;
case R.id.takePicture:
this.mCamera.takePicture(null, null, jpegCallback);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void doPictureResults(byte[] data) {
this.mPreview.releaseCamera();
//Release the camera and send the results of the image to the GetResults view
Intent resultsIntent = new Intent(MainActivity.this, ImageProcessorActivity.class);
resultsIntent.putExtra("image_data", data);
startActivity(resultsIntent);
}
/**
* Handles data for jpeg picture when the picture is taken
*/
PictureCallback jpegCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera mCamera) {Log.e(TAG, "jpegCallback");
String baseExternalDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = String.format("Assist/%d.jpg", System.currentTimeMillis());
FileOutputStream outStream = null;
try {
//Create the directory if needed
File assistDirectory = new File(baseExternalDir + File.separator + "Assist");
assistDirectory.mkdirs();
// Write to SD Card
outStream = new FileOutputStream(baseExternalDir + File.separator + fileName);
outStream.write(data);
outStream.close();
}
catch (FileNotFoundException e) {
Log.e(TAG, "IOException caused by PictureCallback()", e);
}
catch (IOException e) {
Log.e(TAG, "IOException caused by PictureCallback()", e);
}
//This is the type of thing I WANT to do....but its not possible.
MainActivity.doPictureResults();
}
};
}
答案 0 :(得分：1)
一个选项是创建一个PictureCallback实现，保存doPictureResults中所需的信息。目前尚不清楚是否会在其他任何地方调用doPictureResults;如果不是，这很干净并隔离了功能。
另一种方法是让活动本身实现PictureCallback，这样您就可以直接访问所有成员变量而无需进行任何工作。这允许从其他地方调用doPictureResults。
public class MainActivity extends Activity implements PictureCallback {
...
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
....
case R.id.takePicture:
this.mCamera.takePicture(null, null, this);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
...
public void onPictureTaken(byte[] data, Camera mCamera) {
Log.d(TAG, "jpegCallback");
String baseExternalDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = String.format("%d.jpg", System.currentTimeMillis());
...
doPictureResults();
}
}
答案 1 :(得分：0)
您可以在没有实例的类上调用的唯一方法是静态方法，但我不知道这是否会在此处执行。