Android自定义Animation实现View摇摆效果

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="#ffffff"
 android:gravity="center"
 android:orientation="vertical">

 <!--图片-->
 <ImageView
  android:id="@+id/iv_dial"
  android:layout_width="200dp"
  android:layout_height="200dp"
  android:src="@drawable/img"/>

 <!--控制按钮-->
 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_gravity="bottom"
  android:gravity="center"
  android:orientation="horizontal">

  <Button
   android:id="@+id/btn_start"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="开始"/>

  <Button
   android:id="@+id/btn_end"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="结束"/>

 </LinearLayout>

</LinearLayout>

/**
 * 主界面
 * Created by zhuwentao on 2016-08-08.
 */
public class MainActivity extends AppCompatActivity implements View.OnClickListener{

 /** 表盘图片 */
 private ImageView mDialIv;

 /** 开始按钮 */
 private Button mStartBtn;

 /** 结束按钮 */
 private Button mEndBtn;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  initUI();
  initListener();
 }

 /**
  * 初始化UI
  */
 private void initUI() {
  mDialIv = (ImageView) findViewById(R.id.iv_dial);
  mStartBtn = (Button) findViewById(R.id.btn_start);
  mEndBtn = (Button) findViewById(R.id.btn_end);
 }

 /**
  * 初始化监听
  */
 private void initListener() {
  mStartBtn.setOnClickListener(this);
  mEndBtn.setOnClickListener(this);
 }

 @Override
 public void onClick(View v) {
  switch (v.getId()) {
   case R.id.btn_start:
    showAnimation();
    break;
   case R.id.btn_end:
    mDialIv.clearAnimation();
    break;
  }
 }

 /**
  * 设置动画
  */
 private void showAnimation() {
  // 获取自定义动画实例
  CustomRotateAnim rotateAnim = CustomRotateAnim.getCustomRotateAnim();
  // 一次动画执行1秒
  rotateAnim.setDuration(1000);
  // 设置为循环播放
  rotateAnim.setRepeatCount(-1);
  // 设置为匀速
  rotateAnim.setInterpolator(new LinearInterpolator());
  // 开始播放动画
  mDialIv.startAnimation(rotateAnim);
 }
}

/**
 * 左右摇摆动画
 * Created by zhuwentao on 2016-08-08.
 */
public class CustomRotateAnim extends Animation {

 /** 控件宽 */
 private int mWidth;

 /** 控件高 */
 private int mHeight;

 /** 实例 */
 private static CustomRotateAnim rotateAnim;

 /**
  * 获取动画实例
  * @return 实例
  */
 public static CustomRotateAnim getCustomRotateAnim() {
  if (null == rotateAnim) {
   rotateAnim = new CustomRotateAnim();
  }
  return rotateAnim;
 }

 @Override
 public void initialize(int width, int height, int parentWidth, int parentHeight) {
  this.mWidth = width;
  this.mHeight = height;
  super.initialize(width, height, parentWidth, parentHeight);
 }

 @Override
 protected void applyTransformation(float interpolatedTime, Transformation t) {
  // 左右摇摆
  t.getMatrix().setRotate((float)(Math.sin(interpolatedTime*Math.PI*2)*50), mWidth/2, mHeight/2);
  super.applyTransformation(interpolatedTime, t);
 }
}