如何从Uri中获得位图对象(如果我成功地将它存储在 /data/data/MYFOLDER/myimage.png或文件///data/data/MYFOLDER/myimage.png)在我的应用程序中使用它?

有人知道怎么做到吗?


当前回答

我没有看到正确答案,所以我把这个扩展写在这里

fun Context.getBitmap(uri: Uri): Bitmap =
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) ImageDecoder.decodeBitmap(ImageDecoder.createSource(this.contentResolver, uri))
    else MediaStore.Images.Media.getBitmap(this.contentResolver, uri)

代码示例:

val bitmap = context.getBitmap(uri)

提示:你也可以更新活动/片段的扩展,所以你不需要 根本不需要写上下文。再加一点合成糖)

其他回答

try
{
    Bitmap bitmap = MediaStore.Images.Media.getBitmap(c.getContentResolver() , Uri.parse(paths));
}
catch (Exception e) 
{
    //handle exception
}

yes路径必须是这样的格式

file:///mnt/sdcard/filename.jpg

你可以这样做:

protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) {
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent);
    switch(requestCode) {
        case 0:
            if(resultCode == RESULT_OK){
                    Uri selectedImage = imageReturnedIntent.getData();
                    Bundle extras = imageReturnedIntent.getExtras();
                    bitmap = extras.getParcelable("data");
            }
            break;
   }

通过这个,你可以很容易地将uri转换为位图。 希望能帮助你。

val bitmap = context.contentResolver.openInputStream(uri).use { data ->
        BitmapFactory.decodeStream(data)
    }

你需要打开输入流

使用

因为它会在操作完成后自动关闭流。

使用startActivityForResult方法,如下所示

        startActivityForResult(new Intent(Intent.ACTION_PICK).setType("image/*"), PICK_IMAGE);

你可以得到这样的结果:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode != RESULT_OK) {
        return;
    }
    switch (requestCode) {
        case PICK_IMAGE:
            Uri imageUri = data.getData();
            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
            } catch (IOException e) {
                e.printStackTrace();
            }
         break;
    }
}

下面是正确的方法,同时也要注意内存的使用情况:

protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
  super.onActivityResult(requestCode, resultCode, data);
  if (resultCode == RESULT_OK)
  {
    Uri imageUri = data.getData();
    Bitmap bitmap = getThumbnail(imageUri);
  }
}

public static Bitmap getThumbnail(Uri uri) throws FileNotFoundException, IOException{
  InputStream input = this.getContentResolver().openInputStream(uri);

  BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
  onlyBoundsOptions.inJustDecodeBounds = true;
  onlyBoundsOptions.inDither=true;//optional
  onlyBoundsOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
  BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
  input.close();

  if ((onlyBoundsOptions.outWidth == -1) || (onlyBoundsOptions.outHeight == -1)) {
    return null;
  }

  int originalSize = (onlyBoundsOptions.outHeight > onlyBoundsOptions.outWidth) ? onlyBoundsOptions.outHeight : onlyBoundsOptions.outWidth;

  double ratio = (originalSize > THUMBNAIL_SIZE) ? (originalSize / THUMBNAIL_SIZE) : 1.0;

  BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
  bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio);
  bitmapOptions.inDither = true; //optional
  bitmapOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//
  input = this.getContentResolver().openInputStream(uri);
  Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
  input.close();
  return bitmap;
}

private static int getPowerOfTwoForSampleRatio(double ratio){
  int k = Integer.highestOneBit((int)Math.floor(ratio));
  if(k==0) return 1;
  else return k;
}

Mark Ingram的文章中的getBitmap()调用也调用decodeStream(),因此不会丢失任何功能。

引用:

Android:在SD卡上获取图像的缩略图,给定原始图像的Uri 处理大位图