当我调用此函数时，图像视图中没有图像

bitmapFactory.decodefile(filename)显示null ..请帮忙。

这是我的代码：

public Bitmap ShowImage(String imageName,String userImageName )

{

File sdcard_mainDirectory = new File(Environment.getExternalStorageDirectory(),"UserImages").getAbsoluteFile();

File file = new File(sdcard_mainDirectory, userImageName).getAbsoluteFile();

if (file != null) {

try {

String imageInSD = "/sdcard/UserImages/"+userImageName;

Bitmap bitmap = BitmapFactory.decodeFile(imageInSD);

return bitmap;

}

catch (Exception e) {

e.printStackTrace();

}

}

return null;

}