How to share object for all app's activities

Question

I have an animation that I want to apply on every button in my app. So I don't want to call AnimationUtils.loadAnimation() in every activity onCreate method. I would like to call this method only one time when the app is launched to initialize my animation object, and then get it (with a getter) in my different activities. I'm new in Android programming, I was planning to use a Singleton pattern but it looks like to be "unsafe" in Android related to this article and other Stackoverflow pages. (https://programmerr47.medium.com/singletons-in-android-63ddf972a7e7)

Is there anyway to create my Animation at app launching and share it between every activity ? And does it worth to do some optimization ?

Answer 1

I'd suggest extending the android Button/AppCompatButton class, adding the functionality you want to the extended class and using that button everywhere in your app much easier that way and probably the most correct way,

For example:

AnimatedButton.java:

package com.example.myapplication;

import android.content.Context;
import android.util.AttributeSet;

public class AnimatedButton extends androidx.appcompat.widget.AppCompatButton {
    public AnimatedButton(Context context) {
        super(context);
        createAnimation();
    }

    public AnimatedButton(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public AnimatedButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    private void createAnimation() {
        // here create the animation and call
        // setAnimation([YOUR_ANIMATION_HERE]);
        // now you can simply call customButton.animate();
        // from anywhere in the code that uses the button and it should work
    }
}

In your xml where you want to use the button:

<com.example.myapplication.AnimatedButton
            android:id="@+id/btn_animate"
            android:layout_width="180dp"
            android:layout_height="80dp"
            android:text="Animate" />