如何从URI获取位图？

Question

如何从URI获取位图对象（如果我成功将其存储在/data/data/MYFOLDER/myimage.png 或者 file///data/data/MYFOLDER/myimage.png）在我的应用程序中使用它？

有人对如何实现这一目标有想法吗？

Answer 1

. . 重要：请参阅下面的@Mark Ingram和@pjv的答案，以获取更好的解决方案。 . .

您可以尝试一下：

public Bitmap loadBitmap(String url)
{
    Bitmap bm = null;
    InputStream is = null;
    BufferedInputStream bis = null;
    try 
    {
        URLConnection conn = new URL(url).openConnection();
        conn.connect();
        is = conn.getInputStream();
        bis = new BufferedInputStream(is, 8192);
        bm = BitmapFactory.decodeStream(bis);
    }
    catch (Exception e) 
    {
        e.printStackTrace();
    }
    finally {
        if (bis != null) 
        {
            try 
            {
                bis.close();
            }
            catch (IOException e) 
            {
                e.printStackTrace();
            }
        }
        if (is != null) 
        {
            try 
            {
                is.close();
            }
            catch (IOException e) 
            {
                e.printStackTrace();
            }
        }
    }
    return bm;
}

但是请记住，此方法应仅在线程（而非GUI -thread）中调用。我是一个异步。

Answer 2

这是这样做的正确方法：

protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK)
    {
        Uri imageUri = data.getData();
        Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
    }
}

如果您需要加载非常大的图像，则以下代码将其加载到图块中（避免大量内存分配）：

BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(myStream, false);  
Bitmap region = decoder.decodeRegion(new Rect(10, 10, 50, 50), null);

看到答案 这里

Answer 3

这是做到这一点的正确方法，还要保留记忆使用情况：

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帖子中的GetBitMap（）调用也称为DecoDestream（），因此您不会失去任何功能。

参考：

• Android：获得SD卡上图像的缩略图，给定原始图像的URI

• 处理大型位图

Answer 4

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

是的，路径必须以这样的格式

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

Answer 5

这是最简单的解决方案：

Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), uri);

Answer 6

您可以像这样从URI中检索位图

Bitmap bitmap = null;
try {
    bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imageUri);
} catch (IOException e) {
    e.printStackTrace();
}

Answer 7

 private void uriToBitmap(Uri selectedFileUri) {
        try {
            ParcelFileDescriptor parcelFileDescriptor =
                    getContentResolver().openFileDescriptor(selectedFileUri, "r");
            FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
            Bitmap image = BitmapFactory.decodeFileDescriptor(fileDescriptor);


            parcelFileDescriptor.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

Answer 8

Uri imgUri = data.getData();
Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), imgUri);

Answer 9

使用startActivityForresult metod

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

您可以这样得到结果：

@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;
    }
}

Answer 10

您可以完成此结构：

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;
   }

通过此，您可以轻松地将URI转换为位图。希望帮助你。

Answer 11

从移动画廊获取图像URI的完整方法。

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

  if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
                Uri filePath = data.getData();

     try { //Getting the Bitmap from Gallery
           Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
           rbitmap = getResizedBitmap(bitmap, 250);//Setting the Bitmap to ImageView
           serImage = getStringImage(rbitmap);
           imageViewUserImage.setImageBitmap(rbitmap);
      } catch (IOException e) {
           e.printStackTrace();
      }


   }
}

Answer 12

似乎MediaStore.images.media.getBitMap在API 29中弃用。建议的方法是使用ImagedeCoder.Createsource，在API 28中添加。

以下是完成位图的方法：

    val bitmap = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
        ImageDecoder.decodeBitmap(ImageDecoder.createSource(requireContext().contentResolver, imageUri))
    } else {
        MediaStore.Images.Media.getBitmap(requireContext().contentResolver, imageUri)
    }

Answer 13

bitmap imgbitMap = MediaStore.images.Media.getBitMap（this.getContentResolver（），selectedImageuri）;