CODEWITHSUNDEEP
androidandroid-layoutkotlin
jason.kaisersmith
jason.kaisersmith

Reputation: 9650

How to change the android:src in bitmap.xml in code

In my android layout I am setting the background image so that it has a faded look (alpha) by referring to another xml like this:

<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/contraintLayout1"
    ...
    android:background="@drawable/bg_fade"

bg_fade.xml then defined like this:

<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
    android:src="@drawable/background"
    android:alpha="0.3"/>

where background is my actual jpg image in my drawables folder. This works fine, and I get the faded look I want.

Now I need to change the actual background image depending on the user preference. I know I can do this in code for setting a new like this:

contraintLayout1.setBackgroundResource(R.drawable.new_background)

But then I no longer have the faded look, just the "raw" image.

So I somehow need to change the src value in the bg_fade.xml file. But I don't know how I can do this in code.

Can somebody please help? (PS. I am coding in Kotlin)

Upvotes: 0

Views: 355

Answers (1)

Mhmd
Mhmd

Reputation: 111

you can first define a method for change transparency of images like this

public Bitmap changeTransparency(int src, int value) { 
     Bitmap bMap = BitmapFactory.decodeResource(getResources(),src); 
     int width = bMap.getWidth();
     int height = bMap.getHeight();
     Bitmap transBMap = Bitmap.createBitmap(width, height, Config.ARGB_8888);
     Canvas canvas = new Canvas(transBMap);
     canvas.drawARGB(0, 0, 0, 0);
     final Paint paint = new Paint();
     paint.setAlpha(value);
     canvas.drawBitmap(bMap, 0, 0, paint);    
     return transBMap;
}

and then set the returned value to your view's background like this code

view.setBackgroundImage(changeTransparency(R.drawable.new_nackground, ALPHA_VALUE));

i hope be helpful

Upvotes: 1

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