微信曾经推出了一个查找附近好友的功能，大致功能是这样的：屏幕上有一个按钮，长按按钮的时候，会有一圈圈水波纹的动画向外扩散，松手后，动画结束。
现在简单来实现这样的一个动画功能：
思路: 主要用到了下面的蓝色的图片，定义三个ImageView，background都设置为蓝色的图片，然后定义一个包括缩放和透明度变化的动画集，然后每隔一段时间，让3个ImageView依次启动这个动画集，看起来就像蓝色的圆圈像水波纹向外扩散一样。
相关实现逻辑如下：
activity_main.xml
代码语言：javascript复制<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
<ImageView
android:id="@ id/wave1"
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_centerInParent="true"
android:background="@drawable/wave"
/
<ImageView
android:id="@ id/wave2"
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_centerInParent="true"
android:background="@drawable/wave"/
<ImageView
android:id="@ id/wave3"
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_centerInParent="true"
android:background="@drawable/wave" /
<ImageView
android:id="@ id/normal"
android:layout_width="166dp"
android:layout_height="166dp"
android:layout_centerInParent="true"
android:background="@drawable/normal" /
</RelativeLayout MainActivity.java
代码语言：javascript复制package com.jackie.waveanimation;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.view.animation.AnimationSet;
import android.view.animation.ScaleAnimation;
import android.widget.ImageView;
public class MainActivity extends Activity {
private ImageView mNormal, mWave1, mWave2, mWave3;
private AnimationSet mAnimationSet1, mAnimationSet2, mAnimationSet3;
private static final int OFFSET = 600; //每个动画的播放时间间隔
private static final int MSG_WAVE2_ANIMATION = 2;
private static final int MSG_WAVE3_ANIMATION = 3;
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_WAVE2_ANIMATION:
mWave2.startAnimation(mAnimationSet2);
break;
case MSG_WAVE3_ANIMATION:
mWave3.startAnimation(mAnimationSet3);
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNormal = (ImageView) findViewById(R.id.normal);
mWave1 = (ImageView) findViewById(R.id.wave1);
mWave2 = (ImageView) findViewById(R.id.wave2);
mWave3 = (ImageView) findViewById(R.id.wave3);
mAnimationSet1 = initAnimationSet();
mAnimationSet2 = initAnimationSet();
mAnimationSet3 = initAnimationSet();
mNormal.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
showWaveAnimation();
break;
case MotionEvent.ACTION_UP:
clearWaveAnimation();
break;
case MotionEvent.ACTION_CANCEL:
clearWaveAnimation();
}
return true;
}
});
}
private AnimationSet initAnimationSet() {
AnimationSet as = new AnimationSet(true);
ScaleAnimation sa = new ScaleAnimation(1f, 2.3f, 1f, 2.3f,
ScaleAnimation.RELATIVE_TO_SELF, 0.5f,
ScaleAnimation.RELATIVE_TO_SELF, 0.5f);
sa.setDuration(OFFSET * 3);
sa.setRepeatCount(Animation.INFINITE);// 设置循环
AlphaAnimation aa = new AlphaAnimation(1, 0.1f);
aa.setDuration(OFFSET * 3);
aa.setRepeatCount(Animation.INFINITE);//设置循环
as.addAnimation(sa);
as.addAnimation(aa);
return as;
}
private void showWaveAnimation() {
mWave1.startAnimation(mAnimationSet1);
mHandler.sendEmptyMessageDelayed(MSG_WAVE2_ANIMATION, OFFSET);
mHandler.sendEmptyMessageDelayed(MSG_WAVE3_ANIMATION, OFFSET * 2);
}
private void clearWaveAnimation() {
mWave1.clearAnimation();
mWave2.clearAnimation();
mWave3.clearAnimation();
}
} 效果如下：
以上就是本文的全部内容，希望对大家的学习有所帮助。
