Android 实现圆圈扩散水波动画效果两种方法

private Paint centerPaint; //中心圆paintprivate int radius = 100; //中心圆半径private Paint spreadPaint; //扩散圆paintprivate float centerX;//圆心xprivate float centerY;//圆心yprivate int distance = 5; //每次圆递增间距private int maxRadius = 80; //最大圆半径private int delayMilliseconds = 33;//扩散延迟间隔，越大扩散越慢private List<Integer> spreadRadius = new ArrayList<>();//扩散圆层级数，元素为扩散的距离private List<Integer> alphas = new ArrayList<>();//对应每层圆的透明度

<declare-styleable name="SpreadView">  <!--中心圆颜色-->  <attr name="spread_center_color" format="color" />  <!--中心圆半径-->  <attr name="spread_radius" format="integer" />  <!--扩散圆颜色-->  <attr name="spread_spread_color" format="color" />  <!--扩散间距-->  <attr name="spread_distance" format="integer" />  <!--扩散最大半径-->  <attr name="spread_max_radius" format="integer" />  <!--扩散延迟间隔-->  <attr name="spread_delay_milliseconds" format="integer" /></declare-styleable>

public SpreadView(Context context) {  this(context, null, 0);}public SpreadView(Context context, @Nullable AttributeSet attrs) {  this(context, attrs, 0);}public SpreadView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SpreadView, defStyleAttr, 0);  radius = a.getInt(R.styleable.SpreadView_spread_radius, radius);  maxRadius = a.getInt(R.styleable.SpreadView_spread_max_radius, maxRadius);  int centerColor = a.getColor(R.styleable.SpreadView_spread_center_color, ContextCompat.getColor(context, R.color.colorAccent));  int spreadColor = a.getColor(R.styleable.SpreadView_spread_spread_color, ContextCompat.getColor(context, R.color.colorAccent));  distance = a.getInt(R.styleable.SpreadView_spread_distance, distance);  a.recycle();  centerPaint = new Paint();  centerPaint.setColor(centerColor);  centerPaint.setAntiAlias(true);  //最开始不透明且扩散距离为0  alphas.add(255);  spreadRadius.add(0);  spreadPaint = new Paint();  spreadPaint.setAntiAlias(true);  spreadPaint.setAlpha(255);  spreadPaint.setColor(spreadColor);}

@Overrideprotected void onSizeChanged(int w, int h, int oldw, int oldh) {  super.onSizeChanged(w, h, oldw, oldh);  //圆心位置  centerX = w / 2;  centerY = h / 2;}

@Overrideprotected void onDraw(Canvas canvas) {  super.onDraw(canvas);  for (int i = 0; i < spreadRadius.size(); i++) {    int alpha = alphas.get(i);    spreadPaint.setAlpha(alpha);    int width = spreadRadius.get(i);    //绘制扩散的圆    canvas.drawCircle(centerX, centerY, radius + width, spreadPaint);    //每次扩散圆半径递增，圆透明度递减    if (alpha > 0 && width < 300) {      alpha = alpha - distance > 0 ? alpha - distance : 1;      alphas.set(i, alpha);      spreadRadius.set(i, width + distance);    }  }  //当最外层扩散圆半径达到最大半径时添加新扩散圆  if (spreadRadius.get(spreadRadius.size() - 1) > maxRadius) {    spreadRadius.add(0);    alphas.add(255);  }  //超过8个扩散圆，删除最先绘制的圆，即最外层的圆  if (spreadRadius.size() >= 8) {    alphas.remove(0);    spreadRadius.remove(0);  }  //中间的圆  canvas.drawCircle(centerX, centerY, radius, centerPaint);  //TODO 可以在中间圆绘制文字或者图片  //延迟更新，达到扩散视觉差效果  postInvalidateDelayed(delayMilliseconds);}

<com.airsaid.diffuseview.widget.SpreadView  android:id="@+id/spreadView"  android:layout_width="match_parent"  android:layout_height="wrap_content"  app:spread_center_color="@color/colorAccent"  app:spread_delay_milliseconds="35"  app:spread_distance="5"  app:spread_max_radius="90"  app:spread_radius="100"  app:spread_spread_color="@color/colorAccent" />

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android">  <corners android:radius="65dp"/>  <solid android:color="@color/colorAccent"/></shape>

<FrameLayout  android:layout_width="match_parent"  android:layout_height="match_parent">  <!--中心imageView-->  <ImageView    android:id="@+id/iv_wave"    android:layout_width="130dp"    android:layout_height="130dp"    android:layout_gravity="center"    android:background="@drawable/shape_circle" />  <!--中间的imageView-->  <ImageView    android:id="@+id/iv_wave_1"    android:layout_width="130dp"    android:layout_height="130dp"    android:layout_gravity="center"    android:background="@drawable/shape_circle" />  <!--最外层imageView-->  <ImageView    android:id="@+id/iv_wave_2"    android:layout_width="130dp"    android:layout_height="130dp"    android:layout_gravity="center"    android:background="@drawable/shape_circle" /></FrameLayout>

private void setAnim1() {  AnimationSet as = new AnimationSet(true);  //缩放动画，以中心从原始放大到1.4倍  ScaleAnimation scaleAnimation = new ScaleAnimation(1.0f, 1.4f, 1.0f, 1.4f,      ScaleAnimation.RELATIVE_TO_SELF, 0.5f,      ScaleAnimation.RELATIVE_TO_SELF, 0.5f);  //渐变动画  AlphaAnimation alphaAnimation = new AlphaAnimation(1.0f, 0.5f);  scaleAnimation.setDuration(800);  scaleAnimation.setRepeatCount(Animation.INFINITE);  alphaAnimation.setRepeatCount(Animation.INFINITE);  as.setDuration(800);  as.addAnimation(scaleAnimation);  as.addAnimation(alphaAnimation);  iv1.startAnimation(as);}

private void setAnim2() {  AnimationSet as = new AnimationSet(true);  //缩放动画，以中心从1.4倍放大到1.8倍  ScaleAnimation scaleAnimation = new ScaleAnimation(1.4f, 1.8f, 1.4f, 1.8f,      ScaleAnimation.RELATIVE_TO_SELF, 0.5f,      ScaleAnimation.RELATIVE_TO_SELF, 0.5f);  //渐变动画  AlphaAnimation alphaAnimation = new AlphaAnimation(0.5f, 0.1f);  scaleAnimation.setDuration(800);  scaleAnimation.setRepeatCount(Animation.INFINITE);  alphaAnimation.setRepeatCount(Animation.INFINITE);  as.setDuration(800);  as.addAnimation(scaleAnimation);  as.addAnimation(alphaAnimation);  iv2.startAnimation(as);}