实现用一张背景图做循环从左往右平移动画。
1、实现两个animation xml文件，一个起始位置在-100%p ，一个在0%p。设置repeat属性为循环，重复。
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator">
<translate android:fromXDelta="0%p" android:toXDelta="100%p"
android:repeatMode="restart"
android:interpolator="@android:anim/linear_interpolator"
android:repeatCount="infinite"
android:duration="30000" />
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/accelerate_interpolator">
<translate android:fromXDelta="-100%p" android:toXDelta="0%p"
android:repeatMode="restart"
android:interpolator="@android:anim/linear_interpolator"
android:repeatCount="infinite"
android:duration="30000" />
</set>
2、在view的layout里面放两个一样的view做背景，view的动画分别对应上面那两个animation。
<ImageView
android:id="@+id/animation_top_left"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/logo"
android:src="@drawable/home_animation_bg" />
<ImageView
android:id="@+id/animation_top_right" android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/logo"
android:src="@drawable/home_animation_bg" />
Animation anim = AnimationUtils.loadAnimation(mContext, R.anim.home_animation);
ImageView animationTopRightView = (ImageView)this.findViewById(R.id.animation_top_right);
animationTopRightView.startAnimation(anim);
Animation anim2 = AnimationUtils.loadAnimation(mContext, R.anim.home_animation2);
ImageView animationTopLeftView = (ImageView)this.findViewById(R.id.animation_top_left);
animationTopLeftView.startAnimation(anim2);
