背景：重複動畫

重複讓背景淡出、深入的動作：

import android.app.Activity;
import android.os.Bundle;

import android.view.animation.Animation;
import android.view.animation.AnimationUtils;


import android.widget.LinearLayout;

public class BackgroundDemoActivity extends Activity {

    private LinearLayout mLinearLayout;
    private Animation alphaAnim;


   @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
     
        mLinearLayout = (LinearLayout) findViewById(R.id.LinearLayout01);
        alphaAnim = AnimationUtils.loadAnimation(this, R.anim.alpha);
        mLinearLayout.setAnimation(alphaAnim);
      }
}


************************************************
res/anim/alpha.xml:


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

   <alpha android:fromAlpha="1.0"

        android:toAlpha="0.6"

        android:startOffset="0"

        android:duration="5000"

        android:repeatCount="infinite"

        android:repeatMode="reverse"

        />

</set>

********************************

res/layout/main.xml:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/LinearLayout01"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical"

    android:background="@drawable/gradient_selector"

    >

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="@string/hello" />

</LinearLayout>

*********************************

res/drawable/gradient_selector.xml:

<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item>

        <shape>

            <gradient 

                android:angle="90" 

                android:endColor="#FF00FF00" 

                android:startColor="#FFFF0000" 

                android:type="linear" />

        </shape>

        

     </item>

</selector>

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**********************************************
當然也可以換成：traslate

res/anim/translate.xml:


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

    <scale android:fromXScale="1"
          android:toXScale="5"
          android:fromYScale="1"
          android:toYScale="5"
          android:pivotX="50%"
          android:pivotY="50%"
          android:duration="3000"
          android:repeatCount="infinite"
 android:repeatMode="reverse"/>
 
<translate
android:fromXDelta="0"
android:toXDelta="20"
android:fromYDelta="0"
android:toYDelta="20"
android:startOffset="10"
android:duration="3000"
android:repeatCount="infinite"
android:repeatMode="reverse" />

</set>


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或是
res/anim/rotate.xml:


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

    <scale android:fromXScale="3"
          android:toXScale="3"
          android:fromYScale="3"
          android:toYScale="3"
          android:pivotX="50%"
          android:pivotY="50%"
          android:duration="5000"
          android:repeatCount="infinite"
 android:repeatMode="restart"/>
    <rotate
        android:fromDegrees="0"
        android:toDegrees="360"
        android:pivotX="50%"
android:pivotY="50%"
  android:startOffset="10"
android:duration="5000"
android:repeatCount="infinite"
android:repeatMode="restart"/>
 
</set>