Android实现下拉刷新的视图和图标的旋转

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pull_to_refresh_header"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#F3F3F3">
 <RelativeLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:paddingTop="23dp">
  <LinearLayout 
　　　　　　　android:id="@+id/pull_to_refresh_view"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:orientation="vertical"
   android:layout_centerHorizontal="true">
   <TextView
android:id="@+id/pull_to_refresh_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
android:text="@string/pull_to_refresh_text"
    android:textColor="#777777"
    android:textSize="16sp"/>
   <TextView
android:id="@+id/pull_to_refresh_update_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
android:text="@string/pull_to_refresh_update_text"
    android:textColor="#999999"
    android:textSize="14sp"/>
  </LinearLayout>
  <ProgressBar
android:id="@+id/pull_to_refresh_progress"
   android:layout_width="30dp"
   android:layout_height="30dp"
android:layout_toLeftOf="@id/pull_to_refresh_view"
   android:layout_marginRight="22dp"
   android:layout_marginTop="5dp"
   android:indeterminate="true"
android:indeterminateDrawable="@drawable/ic_loading_refresh"
   android:visibility="gone"/>
  <ImageView
   android:id="@+id/pull_to_refresh_image"
   android:layout_width="32dp"
   android:layout_height="32dp"
android:layout_toLeftOf="@id/pull_to_refresh_view"
   android:layout_marginRight="20dp"
   android:layout_marginTop="5dp"
   android:src="@drawable/ic_refresh_down"
   android:scaleType="centerInside"
android:contentDescription="@string/app_name"/>
 </RelativeLayout>
 <View
  android:layout_width="match_parent"
  android:layout_height="15dp"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
 android:drawable="@drawable/ic_loading"
 android:fromDegrees="0"
 android:toDegrees="360"
 android:pivotX="50%"
 android:pivotY="50%" />

private ImageView mPull_to_refresh_image;
private RotateAnimation mFlipAnimation;

...

  mFlipAnimation = new RotateAnimation(0, -180, RotateAnimation.RELATIVE_TO_SELF, 0.5f,
    RotateAnimation.RELATIVE_TO_SELF, 0.5f);
  mFlipAnimation.setInterpolator(new LinearInterpolator());
  mFlipAnimation.setDuration(250);
  mFlipAnimation.setFillAfter(true);

...
mPull_to_refresh_image.startAnimation(mFlipAnimation);

public RotateAnimation(float fromDegrees, float toDegrees, int pivotXType, float pivotXValue,
   int pivotYType, float pivotYValue)