How do I add favourite button to project?

ou always put a fixed background to your favouriteToggleButton, you need to read your SharedPreferences State value and set a background to your favouriteToggleButton, just add these lines to your activity

  @Override
    protected void onResume() {
        super.onResume();
        if (! readstate()) {
            favouriteToggleButton.setBackgroundDrawable(ContextCompat.getDrawable(getApplicationContext(),R.drawable.ic_favorite_border_black_24dp));
        }
        else {
            favouriteToggleButton.setBackgroundDrawable(ContextCompat.getDrawable(getApplicationContext(),R.drawable.ic_favorite_black_24dp));
        }

Hello! you can put your button in your Favourite section with CSS, if you want to do that you need to search on youtube. but here is an example for it:

if you want to make a button, you need to do this in HTML:

<button>Test</button>

and then give it a class like this:

<button class="button">Test</button>

for the CSS, you need to link your CSS file in HTML, to do that , do this in the HTML head part:

<link rel="stylesheet" href="your CSS file name.css">

and then in the CSS part, do this:

.button{position: absolute;
    align-items: center;}

or do this:

.button{
position: absolute;
text-align: center;}

remember this is just for placing the button in the center, if you have any questions ask me! and if I did't respond ask me in discord : SashaGamer#3271