Question

I haven’t found a straight answer to how to make an animation in a button when onClick is called. I’ve got a custom_btn.xml like so:

    <?xml version="1.0" encoding="utf-8"?>
<selector
xmlns:android="http://schemas.android.com/apk/res/android">  
        <item android:state_pressed="true" android:drawable="@drawable/btn_pressed"></item>
        <item android:state_focused="true" android:drawable="@drawable/btn_on"></item>
        <item android:drawable="@drawable/btn"></item>
</selector>

and the animation is in btn_pressed.xml like so:

    <?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android" >
        <item android:drawable="@drawable/btn_on_1" android:duration="30" />
        <item android:drawable="@drawable/btn_on_2" android:duration="30" />
        <item android:drawable="@drawable/btn_on_3" android:duration="30" />
        <item android:drawable="@drawable/btn_on_4" android:duration="30" />
        <item android:drawable="@drawable/btn_on_5" android:duration="30" />

</animation-list>

my problem is that I can’t seem to find the right code to go in the onClickListener here:

        button.setOnClickListener(new View.OnClickListener() { 
        @Override 
        public void onClick(View v) { 

            //-- what is the proper animation call that would go here
         to make btn_pressed.xml cycle only once when pressed?

        } 
    });

thanks!

Answer 1

From the Android documentation:
http://developer.android.com/guide/topics/resources/animation-resource.html

example:
XML file saved at res/anim/rocket.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:oneshot="false">
    <item android:drawable="@drawable/rocket_thrust1" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust2" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust3" android:duration="200" />
</animation-list>

This application code will set the animation as the background for a View, then play the animation:

ImageView rocketImage = (ImageView) findViewById(R.id.rocket_image);
rocketImage.setBackgroundResource(R.drawable.rocket_thrust);

rocketAnimation = (AnimationDrawable) rocketImage.getBackground();
rocketAnimation.start();