Question

我正在尝试找到在MainActivity中实现按钮的最佳方法，该按钮启动相机活动并将图像返回到另一个活动。基本上它将图像返回到活动以向图像添加描述...我认为这是一个好主意是在按下相机按钮时启动单个照片视图活动，并从新活动启动相机活动做其他事之前的结果;但我有一个间歇性的问题，有时相机卡在一个循环中。

也许有更好的方法？我应该首先为结果启动相机活动，然后将图像作为意图传递吗？

这就是我现在所拥有的：

 @Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }else if ( id == R.id.menu_rules ){
        Intent rulesIntent = new Intent(this, RulesActivity.class);
        startActivity(rulesIntent);
        return true;
    }else if ( id == R.id.menu_import_photo ){
        //pull in an image from the gallery

        return true;
    }else if ( id == R.id.menu_item_new_photo ){
        startActivity(new Intent(MainActivity.this, SinglePhotoViewActivity.class));
    }
    return super.onOptionsItemSelected(item);
}

和接收活动..

public class SinglePhotoViewActivity extends Activity {

private static final String LOG_TAG = "Simple Camera App";
private static int TAKE_PICTURE = 1001;
private ImageView imageView;
private Uri imageUri;
private Bitmap bitmap;
private TextView textView;
private EditText editText;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_single_photo_view);

    if ( bitmap == null )
        takePhoto();


}

public void takePhoto(){
    Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
    File photo = new File(Environment
            .getExternalStoragePublicDirectory(Environment
                    //this will continually overwrite the same file
                    //need to implement a date/ time string
                    //to save as file name.
                    .DIRECTORY_PICTURES), "pic.jpg");
    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photo));
    imageUri = Uri.fromFile(photo);
    startActivityForResult(intent, TAKE_PICTURE);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    switch(requestCode) {
        case 1001:
            if(resultCode == Activity.RESULT_OK) {
                getContentResolver().notifyChange(imageUri, null);
                imageView = (ImageView )findViewById(R.id.ivCameraImageView);
                ContentResolver contentResolver = getContentResolver();

                try {
                    bitmap = android.provider.MediaStore.Images.Media.getBitmap(contentResolver,
                        imageUri);
                    imageView.setImageBitmap(bitmap);
                } catch(Exception e) {
                    Toast.makeText(SinglePhotoViewActivity.this, "failed to load",
                             Toast.LENGTH_LONG).show();
                    Log.e(LOG_TAG, e.toString());
                }
            }
    }
}
}

Answer 1

您的情况类似于启动ACTION_IMAGE_CAPTURE意图时经常发生的情况（请参阅例如 Android startCamera gives me null Intent and ... does it destroy my global variable? ）。

原因是系统可能决定销毁调用者活动（在您的情况下为SinglePhotoViewActivity），并在启动的活动（在您的情况下，系统Camera活动）返回结果后再次重新创建它。

最终修复涉及在调用活动中实现onSaveInstanceState(Bundle)。但在你的具体情况下，有一条捷径。检查onCreate()中的意图，如果它来自MainActivity，则启动相机。否则，就像现在要接收onActivityResult()一样。

在onCreate中启动摄像头会导致间歇性问题

1 个答案: