How to remove Backgroundsource from button in Android

Andreas ss 721 Reputation points
2022-07-10T23:36:10.393+00:00

Hello,

I have a little problem to Remove a Resource.Drawable.borderGREEN_RED from a button in android.
I will tell what I do step by step:

  1. I SetBackgroundResource(ResRource.Drawable.borderGREEN_RED); to the button which works.
    The button is painted RED and sets a GREEN border. This works great!
  2. Now I need to somehow Remove this Resource.Drawable.borderGREEN_RED from the button so
    it has the state as it was before I did set it. I am trying to do that with:
    button1.SetBackgroundResource(0);
  3. The whole problem comes here. What I need to do in this step is to SetColorFilter on the button
    like this to make it completely yellow:
    button1.Background.SetColorFilter(Android.Graphics.Color.Yellow, Android.Graphics.PorterDuff.Mode.Multiply);

The problem on step 3 is that the .Background property is NULL because of what I did in step 2
where I put: button1.SetBackgroundResource(0);

My question would be. How do I remove the BackgroundResource that I put in step 1 so I can SetColorFilter in step 3?

Thank you!

                                Android.Views.View view = LayoutInflater.Inflate(Resource.Layout.Main, null);  
                                Button button1 = view.FindViewById<Button>(Resource.Id.button10);  
  
                                button1.SetBackgroundResource(Resource.Drawable.borderGREEN_RED); //STEP 1   
                                button1.SetBackgroundResource(0); //STEP 2   
                                button1.Background.SetColorFilter(Android.Graphics.Color.Yellow, Android.Graphics.PorterDuff.Mode.Multiply); //STEP 3  
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A Microsoft open-source app platform for building Android and iOS apps with .NET and C#.
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Accepted answer
  1. Leon Lu (Shanghai Wicresoft Co,.Ltd.) 63,916 Reputation points Microsoft Vendor
    2022-07-11T05:16:41.767+00:00

    Hello,​

    How do I remove the BackgroundResource that I put in step 1 so I can SetColorFilter in step 3?

    If you set SetBackgroundResource(0); //STEP 2 , Button do not have any background. The value of Background property is NULL in step 3.

    Remove this Resource.Drawable.borderGREEN_RED from the button so, it has the state as it was before I did set it

    You can get the Background Drawable before you execute step2. Then you can set it in Step 2 like following code.

       Button  button1 = FindViewById<Button>(Resource.Id.button10);  
       //get  state as it was before you did set it  
       Android.Graphics.Drawables.Drawable  btnDrawable = button1.Background;  
         
       button1.SetBackgroundResource(Resource.Drawable.borderGREEN_RED); //STEP 1   
         
       //STEP 2: set the state as it was before you did set it  
         
                   button1.Background=btnDrawable; //STEP 2  
    

    Best Regards,

    Leon Lu


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