Question

Hi I have a layout which I’m using to fill my page and I have to set a background image held in my drawable folder in that layout.

I want to then set the alpha value of the image to something quite low almost make the image like a water mark.

my xml looks like

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/background"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="@drawable/main_background" >

As you can see I have assigned an id to the layout

I thought in my oncreate I could do something like this?

View backgroundimage = (View) findViewById(R.id.background);
backgroundimage.setAlpha(80);

This is not working however I suspect its because I’m trying to cast the background as a View what should I cast it as?

Answer 1

Try to use:

Drawable.setAlpha();

You should do something like this:

View backgroundImage = findViewById(R.id.background);
Drawable background = backgroundImage.getBackground();
background.setAlpha(80);