Android ImageView控件的MaxWidth、MaxHeight不起作用

LinearLayout ll = new LinearLayout(ConsumeInfo.this);  
ll.setOrientation(LinearLayout.HORIZONTAL);  			        
//设置小图标  
ImageView imageView = new ImageView(ConsumeInfo.this);              
Bitmap bitmap = BitmapFactory.decodeFile((String)mData.get(position).get("imgpath")); 
imageView.setImageBitmap(bitmap);  
imageView.setAdjustViewBounds(true);  
imageView.setMaxHeight(50);
imageView.setMaxWidth(50);
ll.addView(imageView);