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How to run an animation from an XML file?

I have created an animation file in the animator directory of android studio. I am trying to change the colour of a button.

<?xml version="1.0" encoding="utf-8"?>
<objectAnimator android:duration="500"
xmlns:android="http://schemas.android.com/apk/res/android"
android:propertyName="color"
android:valueTo="#333333"
android:valueFrom="@color/start_button"
/>


Then i tried to run the animation from my MainActivity.java, but when i click on the button to run the animation the app crashes.

public void btnClick(View view)
AnimatorSet set = (AnimatorSet) AnimatorInflater.loadAnimator(this, R.animator.rotation);
set.setTarget(view); // set the view you want to animate
set.start();



res/anim

2 Answers
2

android:propertyName

android:propertyName

String. Required. The object's property to animate, referenced by its
name. For example you can specify "alpha" or "backgroundColor" for a
View object. The objectAnimator element does not expose a target
attribute, however, so you cannot set the object to animate in the XML
declaration. You have to inflate your animation XML resource by
calling loadAnimator() and call setTarget() to set the target object
that contains this property.

alpha

backgroundColor

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

<objectAnimator android:duration="500"
xmlns:android="http://schemas.android.com/apk/res/android"
android:propertyName="backgroundColor"
android:valueTo="#333333"
android:valueFrom="@color/start_button"
/>
</set>


Inflating and run AnimatorSet

AnimatorSet set = (AnimatorSet) AnimatorInflater.loadAnimator(getActivity(), R.animator.rotation);
set.setTarget(view); // set the view you want to animate
set.start();


Update

If you set propertyName="color" then the target view shall have setColor method.

propertyName="color"

setColor

W/PropertyValuesHolder: Method setColor() with type int not found on target class class android.support.v7.widget.Toolbar

In general propertyName="someName" then target view shall has method setSomeName

propertyName="someName"

setSomeName

Ex. If you need to change custom view angle then propertyName="angle"
and custom target view must implement setAngle

angle

propertyName="angle"

setAngle

Try this.

public void onClick(View v)
int colorStart = v.getSolidColor();
int colorEnd = 0xFFFF0000;
ValueAnimator colorAnim = ObjectAnimator.ofInt(v,"backgroundColor",colorStart, colorEnd);
colorAnim.setDuration(2000);
colorAnim.setEvaluator(new ArgbEvaluator());
colorAnim.setRepeatCount(1);
colorAnim.setRepeatMode(ValueAnimator.REVERSE);
colorAnim.start();




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