How to change the opacity of an image.

Question

I have an background image set to an ImageView, Now i want to change the opacity of an image without, for that i write this code to change the opacity of ImageView, but when i do so it remove the background image from the image view, So my question is how can i change the opacity of ImageView without removing background image form it.

Code i used is:

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

imageView.setBackgroundResource(R.drawable.theme1_page_header); // Set background image

int opacity = 100; // from 0 to 255
imageView.setBackgroundColor(opacity * 0x1000000); // change opacity of image

Answer 1

the most important part of alpha is that the value has to be decimal

0 = transparent and 1 = visible

so 0.5 is half way visible

in the XML you can do

<ImageView
        android:layout_width="30dp"
        android:layout_height="35dp"
        android:id="@+id/imageView"
        android:alpha="0.4" // <-----------------  this is the fun part
        android:layout_alignParentRight="false"
        android:background="@drawable/imagename"
        android:layout_alignParentLeft="false"
        android:layout_alignParentTop="false"
        android:layout_alignWithParentIfMissing="false"
        android:layout_marginLeft="100dp"
        android:layout_alignParentBottom="false"
        android:layout_alignParentStart="false"
        android:layout_alignTop="@+id/bar"
        android:layout_marginTop="30dp"/>

Answer 2

For Api >=16 . Use setImageAlpha as your practice because setAlpha will be deprecated in coming future. `

ImageView.setAlpha(int) has been renamed to ImageView.setImageAlpha(int) to avoid confusion. See Detail Explanation here