Android - 打开相机活动而不是图片库

Question

我创建了一个活动，允许用户在该活动中向 ImageView 添加图片。我创建了一个按钮，用于打开活动的上下文菜单并为用户提供从图库中选择图片或使用相机拍照的选项。

如果我选择第一个选项 - 从图库中挑选图片，它可以正常工作。图库打开，我选择了图片，我的活动被恢复，图片被添加到 ImageView。

选择第二个选项、拍照并恢复我的活动后，奇怪的事情开始发生：

1. 如果我再次打开上下文菜单并尝试打开图库，相机 活动改为打开
2. 我关闭相机活动并继续我的活动，显示“使用完成操作”对话框
3. 我打开图库，选择一张图片并抛出 NullPointerException
   

为什么我会出现这种行为和异常？我已经尝试搜索类似的主题，但没有找到解决方案。
以下是我的活动的方法

public boolean onContextItemSelected(MenuItem item) {
    super.onContextItemSelected(item);
    switch(item.getItemId()) {
    case R.id.cm_Select_picture: {
        // TODO open gallery
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent, ""), RC_SELECT_PICTURE);
    }
    case R.id.cm_Take_picture: {
        // TODO open camera 
        Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(cameraIntent, RC_TAKE_PICTURE);
    }
    default: return false;
    }
}

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(resultCode == RESULT_OK) {
        switch(requestCode) {
        case RC_SELECT_PICTURE: {
            Log.d(TAG, "Case select picture");
            Uri selectedImageUri = data.getData();
            String[] filePathColumn = {MediaStore.Images.Media.DATA};

            Cursor cursor = getContentResolver().query(selectedImageUri
                    , filePathColumn, null, null, null);
            cursor.moveToFirst();
            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            String filePath = cursor.getString(columnIndex);
            cursor.close();
            Bitmap pic = BitmapFactory.decodeFile(filePath);
            goodsImage.setImageBitmap(pic);
        }
        case RC_TAKE_PICTURE: {
            Log.d(TAG, "Case take picture");
            if(data.getExtras().get("data") != null) {
                Bitmap pic = (Bitmap) data.getExtras().get("data");
                goodsImage.setImageBitmap(pic);
            }
        }
        }
    }
}

04-26 01:34:59.529: E/AndroidRuntime(20531): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=3, result=-1, data=Intent { dat=content://media/external/images/media/9 }} to activity {com.forestassistant/com.statistics.GoodsActivity}: java.lang.NullPointerException

Answer 1

我曾经从我的活动中调用相机活动，并且效果很好，这是我的代码：

 setMediaUri(getNewMediaFilePath(actOwner.getContentResolver()));
                Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
                cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, getMediaUri());
                startActivityForResult(cameraIntent, CAMERA_CAPTURE_REQUEST_CODE);

以及何时回调

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK 
            && requestCode == CAMERA_CAPTURE_REQUEST_CODE) {
        Drawable toRecycle= imgView.getDrawable();
        if (toRecycle != null) {                
            ((BitmapDrawable)imgView.getDrawable()).getBitmap().recycle();
        }
        mImg = decodeFileIntoRequiredSize(getPath(getMediaUri(),this), requiredSizeForImage);
        imgView.setImageBitmap(mImg);           
    } 
public Bitmap decodeFileIntoRequiredSize(String filePath,int requiredSize){
    Bitmap b = null;
    try {
        File f = new File(filePath);
        //Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;

        FileInputStream fis = new FileInputStream(f);
        BitmapFactory.decodeStream(fis, null, o);
        fis.close();
        int scale = 1;
        if (o.outHeight > requiredSize || o.outWidth > requiredSize) {
            scale = (int)Math.pow(2, (int) Math.round(Math.log(requiredSize / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
        }

        //Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        fis = new FileInputStream(f);
        b = BitmapFactory.decodeStream(fis, null, o2);
        fis.close();
    } catch (IOException e) {
    }
    return b;
}
public String getPath(Uri uri,Activity act) {
    String[] projection = { MediaStore.Images.Media.DATA };
    Cursor cursor = act.managedQuery(uri, projection, null, null, null);
    if (cursor != null) {       
        int column_index = cursor
                .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        return cursor.getString(column_index);
    } else
        return null;
}
public Uri getNewMediaFilePath(ContentResolver contentResolver) {
    ContentValues values = new ContentValues();

    //create the directory
    // /mnt/sdcard/DCIM/Camera/IMG_20111101_111922.jpg
    String cameraDir = "/Camera";
    //File dir1 = act.getExternalFilesDir(Environment.DIRECTORY_DCIM);
    File dir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getPath()+cameraDir);
    if(!dir.exists()) dir.mkdir();

    //use date as filename
    String name = "IMG_" + (String) android.text.format.DateFormat.format("yyyyMMdd_hhmmss",new Date());
    String path = dir.getPath()+File.separator + name;
    values.put(MediaStore.MediaColumns.TITLE, name);
    values.put(MediaStore.MediaColumns.DATE_ADDED, System.currentTimeMillis());
    Uri base = null;
    path += ".jpg";
    base = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    values.put(MediaStore.MediaColumns.MIME_TYPE, "image/jpeg");
    values.put(MediaStore.MediaColumns.DATA, path);
    return contentResolver.insert(base, values);
}

希望对您有所帮助。