如何将相机意图设置为主要活动

Question

I want to launch the camera once a user opens up my application.

Right now I have this, and it works fine. When the user launches my application, it automatically opens up the camera. However, then the user hits the "back" button after taking an image, it opens up a blank activity.

How do I get it to go back to the camera?

public class MainActivity extends AppCompatActivity {

private static final int REQUEST_TAKE_PHOTO = 0;

// The URI of photo taken with camera
private Uri mUriPhotoTaken;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    takePhoto();
}

// Deal with the result of selection of the photos and faces.
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        Uri imageUri;
        if (data == null || data.getData() == null) {
            imageUri = mUriPhotoTaken;
        } else {
            imageUri = data.getData();
        }
        Intent intent = new Intent(MainActivity.this, Result.class);
        intent.setData(imageUri);
        startActivity(intent);
    }
}

// Launch the camera to allow the user to take a photo
public void takePhoto(){
    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if(intent.resolveActivity(getPackageManager()) != null) {
        // Save the photo taken to a temporary file.
        File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        try {
            File file = File.createTempFile("IMG_", ".jpg", storageDir);
            mUriPhotoTaken = Uri.fromFile(file);
            intent.putExtra(MediaStore.EXTRA_OUTPUT, mUriPhotoTaken);
            startActivityForResult(intent, REQUEST_TAKE_PHOTO);
        } catch (IOException e) {
            Log.d("ERROR", e.getMessage());
        }
    }
}
}

Answer 1

尝试在onStart()而不是onCreate()调用takePhoto()方法，然后在onStop()调用finish()方法。

Answer 2

Try it.

        @Override
        public void onBackPressed() {
            super.onBackPressed();
            Intent intent = new Intent(this, ActivityYouWantToOpen.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            finish();
        }