最近再做一个教育类的项目。在做一些学习工具的时候，美工提出了一些要求，大致如下：
其实实现过程也不难，，大致就是对一个视图控件添加一个圆形的背景，然后该视图进行动画处理，膨胀的同时，透明度增大，收缩的同时，透明度降低。
我在例子中是使用了TextView，所以首先对TextView添加一个圆形的背景：
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android=""android:shape="oval" ><sizeandroid:height="90dp"android:width="90dp" /><solid android:color="@color/color_space_studytools_red" /><corners android:radius="180dip" /><paddingandroid:bottom="4dip"android:left="4dip"android:right="4dip"android:top="4dip" /></shape>然后为TextView添加动画，包括调整大小的ScaleAnimation和调整透明度的AlphaAnimation。调整大小有两个部分，膨胀和收缩。在膨胀完毕后马上收缩，也就是对膨胀的动画进行监听，在onAnimationEnd()方法里面进行收缩，
// 按钮模拟心脏跳动private void playHeartbeatAnimation(final View heartbeatView) {AnimationSet swellAnimationSet = new AnimationSet(true);swellAnimationSet.addAnimation(new ScaleAnimation(1.0f, 1.8f, 1.0f, 1.8f, Animation.RELATIVE_TO_SELF, 0.5f,Animation.RELATIVE_TO_SELF, 0.5f));swellAnimationSet.addAnimation(new AlphaAnimation(1.0f, 0.3f));swellAnimationSet.setDuration(500);swellAnimationSet.setInterpolator(new AccelerateInterpolator());swellAnimationSet.setFillAfter(true);swellAnimationSet.setAnimationListener(new AnimationListener() {@Overridepublic void onAnimationStart(Animation animation) {}@Overridepublic void onAnimationRepeat(Animation animation) {}@Overridepublic void onAnimationEnd(Animation animation) {AnimationSet shrinkAnimationSet = new AnimationSet(true);shrinkAnimationSet.addAnimation(new ScaleAnimation(1.8f, 1.0f, 1.8f, 1.0f, Animation.RELATIVE_TO_SELF,0.5f, Animation.RELATIVE_TO_SELF, 0.5f));shrinkAnimationSet.addAnimation(new AlphaAnimation(0.3f, 1.0f));shrinkAnimationSet.setDuration(1000);shrinkAnimationSet.setInterpolator(new DecelerateInterpolator());shrinkAnimationSet.setFillAfter(false);heartbeatView.startAnimation(shrinkAnimationSet);// 动画结束时重新开始，实现心跳的View}});heartbeatView.startAnimation(swellAnimationSet);}心跳的效果是要不停地膨胀和收缩，所以要开一个线程来处理，每当收缩完毕后重新膨胀。
private class HeatbeatThread extends Thread {public void run() {try {sleep(100);} catch (InterruptedException e1) {e1.printStackTrace();}while (true) {runOnUiThread(new Runnable() {public void run() {for (View view : heartbeatViews) {playHeartbeatAnimation(view);}}});try {Thread.sleep(1500);} catch (InterruptedException e) {e.printStackTrace();}}};}最后和Activity的生命周期结合，对线程进行开始和结束。
private Thread heartbeatThread;/** * 开始心跳 */private void startHeartBeat() {if (heartbeatThread == null) {heartbeatThread = new HeatbeatThread();}if (!heartbeatThread.isAlive()) {heartbeatThread.start();}}/** * 停止心跳 */private void stopHeartBeat() {if (heartbeatThread != null && heartbeatThread.isInterrupted()) {heartbeatThread.interrupt();heartbeatThread = null;System.gc();}}@Overrideprotected void onResume() {super.onResume();startHeartBeat();}@Overrideprotected void onPause() {super.onPause();stopHeartBeat();}
Demo下载为：
的这一半更多地赢取上帝掌握的那一半。
