Android: Using ObjectAnimator to translate a View with fractional values of the View's dimension

Solution 1:

Actually object animators accept fractional values. But maybe you didn't understand the underlying concept of an objectAnimator or more generally a value animator. A value animator will animate a value related to a property (such as a color, a position on screen (X,Y), an alpha parameter or whatever you want). To create such a property (in your case xFraction and yFraction) you need to build your own getters and setters associated to this property name. Lets say you want to translate a FrameLayout from 0% to 25% of the size of your whole screen. Then you need to build a custom View that wraps the FrameLayout objects and write your getters and setters.

public class SlidingFrameLayout extends FrameLayout
{
    private static final String TAG = SlidingFrameLayout.class.getName();

    public SlidingFrameLayout(Context context) {
        super(context);
    }

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

    public float getXFraction()
    {
        int width = getWindowManager().getDefaultDisplay().getWidth();
        return (width == 0) ? 0 : getX() / (float) width;
    }

    public void setXFraction(float xFraction) {
        int width = getWindowManager().getDefaultDisplay().getWidth();
        setX((width > 0) ? (xFraction * width) : 0);
    }
}

Then You can use the xml way to declare the object animator putting xFraction under the property xml attribute and inflate it with a AnimatorInflater

<?xml version="1.0" encoding="utf-8"?>
<objectAnimator 
xmlns:android="http://schemas.android.com/apk/res/android"
android:propertyName="xFraction" 
android:valueType="floatType"
android:valueFrom="0"
android:valueTo="0.25" 
android:duration="500"/>

or you can just use the java line code

ObjectAnimator oa = ObjectAnimator.ofFloat(menuFragmentContainer, "xFraction", 0, 0.25f);

Hope it helps you!

Olivier,

Solution 2:

Android SDK implementation of FragmentTransaction expects an Animator while, for some obscure reason, the support library implementation expects an Animation, if you use Fragment implementation from support library your translate animation will work

Solution 3:

Here is an important gotcha for those who are trying to create view animations like translate and scale.

Property animations are located in a directory named "animator": res/animator/filename.xml

BUT, view animations must be put in a directory simply called "anim": res/anim/filename.xml

I first put my view animation in an "animator" folder, and was confused about Android Studio complaining about how translate was not a valid element. So, NO, view animations are not deprecated. They just have their own location for some confusing reason.