从Uri获取位图

protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_view_image); 

    imageView = (ImageView) findViewById(R.id.imageView); 

    Intent intent = getIntent(); 
    Uri imageUri = intent.getData(); 
    // Picasso.with(this).load(imageUri).into(imageView); 

    if(imageUri == null){ 
     Log.d(TAG, "Check"); 
    } 






     //BitmapFactory.Options options = new BitmapFactory.Options(); 
    // options.inSampleSize = 8; 
    // bm = MediaStore.Images.Media.getBitmap(getContentResolver(),imageUri); 

    Bitmap bm = null; 

    try{ 
     InputStream image; 
    try{ 
     image = getContentResolver().openInputStream(imageUri); 
     bm = BitmapFactory.decodeStream(image); 
    } catch (FileNotFoundException e) { 
     e.printStackTrace(); 
    } 
    } 
    catch (Exception e){ 
     e.printStackTrace(); 
    } 




    //BitmapFactory.Options options = new BitmapFactory.Options(); 
    // bm = BitmapFactory.decodeFile(file.getAbsolutePath(),options); 


    if ((bm == null)) { 
     prints("It doesn't work"); 
    } 

    //Log.d(TAG,"Going to convert image."); 
     imageView.setImageBitmap(bm);

我看了一堆StackOverFlow问题，我已经尝试过所有这些，如您在注释代码中所见。我正在尝试获取照片拍摄时未更改的位图。位图的像素位置对于我的目标至关重要。图像质量很高，也许是一个更大的文件。我的位图总是空的，我确定我的Uri不是。有任何想法吗？从Uri获取位图

来源

2017-03-09 vinlord

'InputStream的图像

private void setImage(String path, CircleImageView img) { options = new DisplayImageOptions.Builder() .cacheInMemory(true) .cacheOnDisk(true) .considerExifParams(true) .bitmapConfig(Bitmap.Config.RGB_565) .showImageOnLoading(R.drawable.user) .showImageForEmptyUri(R.drawable.user) .showImageOnFail(R.drawable.user) .build(); ImageLoader.getInstance().displayImage(path, img, options, new SimpleImageLoadingListener() { @Override public void onLoadingStarted(String imageUri, View view) { super.onLoadingStarted(imageUri, view); } @Override public void onLoadingFailed(String imageUri, View view, FailReason failReason) { super.onLoadingFailed(imageUri, view, failReason); } @Override public void onLoadingCancelled(String imageUri, View view) { super.onLoadingCancelled(imageUri, view); } @Override public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) { super.onLoadingComplete(imageUri, view, loadedImage); } }, new ImageLoadingProgressListener() { @Override public void onProgressUpdate(String s, View view, int i, int i1) { } }); }

使用通用的图像加载器;'。请不要写不可读的代码。不要将输入流命名为图像。 – greenapps

该文件具有太大的分辨率，无法制作位图。没有足够的内存来构建位图，因此返回null。

尝试使用非常小的图像文件来查看。

来源

2017-03-09 09:15:16 greenapps

如果您的移动存储位于下面的代码中，您可以直接从URI获取位图。

public Bitmap getBitmapFromURI(Uri uri){ 
     String[] filePathColumn = {MediaStore.Images.Media.DATA}; 
     Cursor cursor = getActivity().getContentResolver().query(uri, filePathColumn, null, null, null); 
     if(cursor!=null){ 
      cursor.moveToFirst(); 
      int columnIndex = cursor.getColumnIndex(filePathColumn[0]); 
      File f_image = new File(cursor.getString(columnIndex)); 
      cursor.close(); 
      BitmapFactory.Options o2 = new BitmapFactory.Options(); 
      return BitmapFactory.decodeFile(f_image.getAbsolutePath(), o2); 
     } 
     return null; 
    }

如果文件太大无法加载..您需要压缩图像并显示。为此，您还需要使用Async Task。

我使你可以用它查看大图

public class ConvertBase64Task extends AsyncTask<Void, Bitmap, Bitmap> { 

    private ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
    private File file; 

    private int CompressionRatio = 80; //You can change it by what ever ratio you want. in 0 to 100. 

    private boolean shouldrotate = true; 





    private ImageCompressiorListner imageCompressiorListner; 

    public ConvertBase64Task(File file) { 
     this.file = file; 
    } 

    public void setRotation(boolean isRotate) { 
     shouldrotate = isRotate; 
    } 


    public void setCompressionRatio(int Ratio) { 
     CompressionRatio = Ratio; 
    } 


    public void setImageCompressiorListner(ImageCompressiorListner imageCompressiorListner) { 
     this.imageCompressiorListner = imageCompressiorListner; 
    } 

    @Override 
    protected void onPreExecute(){ 
    } 

    @Override 
    protected Bitmap doInBackground(Void... params) { 



      try { 
       //***** Fatching file 
       //*****Code for Orientation 
       Matrix matrix = new Matrix(); 

       if (shouldrotate) { 
        ExifInterface exif1 = new ExifInterface(file.getAbsolutePath()); 
        int orientation = exif1.getAttributeInt(
          ExifInterface.TAG_ORIENTATION, 1); 
        Log.d("EXIF", "Exif: " + orientation); 
        if (orientation == 6) { 
         matrix.postRotate(90); 
        } else if (orientation == 3) { 
         matrix.postRotate(180); 
        } else if (orientation == 8) { 
         matrix.postRotate(270); 
        } else { 
         matrix.postRotate(0); 
        } 
       } else { 
        matrix.postRotate(0); 
       } 

       try { 

        BitmapFactory.Options option = new BitmapFactory.Options(); 
        option.inJustDecodeBounds = true; 
        BitmapFactory.decodeFile(file.getAbsolutePath(), option); 

        int file_size = Integer.parseInt(String.valueOf(file.length()/1024)); 
        Log.e("ImageSize", "" + file_size); 


        int scale = 1; 

        if (file_size < 512) { 
         Log.e("image size is good", "image size is less"); 
        } else if (file_size < 1024) { 
         Log.e("image size is 1 mb", "image size is heavy"); 
         scale = 2; 
        } else if (file_size < 1536) { 
         Log.e("image size is 1.5 mb", "image size is heavy"); 
         scale = 2; 
        } else if (file_size < 2048) { 
         Log.e("image size is 2 mb", "image size is heavy"); 
         scale = 4; 
        } else { 
         Log.e("image size > 2 mb", "image size is heavy"); 
         scale = 4; 
        } 

        Log.e("Scale", "Finaly Scaling with " + scale); 

        BitmapFactory.Options o2 = new BitmapFactory.Options(); 
        o2.inSampleSize = scale; 
        Bitmap pickimg = BitmapFactory.decodeFile(file.getAbsolutePath(), o2); 

        if (pickimg.getWidth() > 1280 || pickimg.getHeight() > 1000) { 

         int width = pickimg.getWidth(); 
         int height = pickimg.getHeight(); 

         while (width > 1280 || height > 700) { 
          width = (width * 90)/100; 
          height = (height * 90)/100; 
         } 

         pickimg = Bitmap.createScaledBitmap(pickimg, width, height, true); 
        } else { 
         pickimg = Bitmap.createBitmap(pickimg, 0, 0, pickimg.getWidth(), pickimg.getHeight(), matrix, true); // rotating bitmap 
        } 

        pickimg.compress(Bitmap.CompressFormat.JPEG, CompressionRatio, baos); 
        return pickimg; 

       } catch (OutOfMemoryError e) { 
        e.printStackTrace(); 
        return null; 
       } catch (Exception e) { 
        e.printStackTrace(); 
        return null; 

       } 

      } catch (Throwable e) { 
       e.printStackTrace(); 
       return null; 
      } 

    } 

    @Override 
    protected void onPostExecute(Bitmap result) { 
     super.onPostExecute(result); 
     if (result != null) { 
      if(imageCompressiorListner!=null){ 
       imageCompressiorListner.onImageCompressed(result); 
      } 
     } else { 
      if(imageCompressiorListner!=null){ 
       imageCompressiorListner.onError(); 
      } 
     } 
    } 


    public interface ImageCompressiorListner { 
     void onImageCompressed(Bitmap bitmap); 
     void onError(); 
    } 
}

一个图像压缩任务，您可以使用此如下

ConvertBase64Task task = new ConvertBase64Task(File Object of Image); 
     task.setImageCompressiorListner(new ConvertBase64Task.ImageCompressiorListner() { 
     @Override 
     public void onImageCompressed(Bitmap bitmap) { 

     } 

     @Override 
     public void onError() { 

     } 
    }); 
    task.execute();

希望这将帮助你。

来源

2017-03-09 10:27:56

Down Voters，我可以知道代码出了什么问题吗？ –

我认为下面的代码将帮助您为SimpleImageLoadingListener()

来源

2017-03-09 10:35:11

从Uri获取位图

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