Android仿微信雷达扫描效果的实现方法

public class ShapeDrawableActivity extends AppCompatActivity { private ImageView ivLightbeam; private ObjectAnimator radarScanAnim; // 扫描动画 private int width; private int height; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_shape_drawable);  ivLightbeam = (ImageView) findViewById(R.id.ivLightbeam); } @Override protected void onResume() {  super.onResume();  startScan(); } @Override public void onWindowFocusChanged(boolean hasFocus) {  super.onWindowFocusChanged(hasFocus);  if (height == 0 || width == 0) {   //获取屏幕长、宽   width = ScreenUtils.getScreenWidth(this);   height = ScreenUtils.getScreenHeight(this);   //根据屏幕长、宽计算扫描圆的直径   int diameter = (int) Math.sqrt(Math.pow(height, 2) + Math.pow(width, 2));   //修改光束的大小，使光束可以扫描到整个屏幕   FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(diameter, diameter);   ivLightbeam.setLayoutParams(layoutParams);   //将扫描光束的中心移至屏幕内容中心   int offsetX = (width - diameter) / 2;   int offsetY = (height - diameter) / 2 + ScreenUtils.getStatusHeight(this) / 2;   ivLightbeam.setX(offsetX);   ivLightbeam.setY(offsetY);  } } @Override protected void onPause() {  super.onPause();  stopScan(); } // 开始扫描 private void startScan() {  radarScanAnim = ObjectAnimator.ofFloat(ivLightbeam, "rotation", 0f, 360f);  radarScanAnim.setDuration(2000); //2秒扫描一圈  radarScanAnim.setInterpolator(new LinearInterpolator());  radarScanAnim.setRepeatCount(ObjectAnimator.INFINITE);//循环扫描  ivLightbeam.setVisibility(View.VISIBLE);  radarScanAnim.start(); } // 停止扫描 private void stopScan() {  ivLightbeam.setVisibility(View.GONE);  radarScanAnim.end(); }}

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#FA000000" android:clipToPadding="false" android:fitsSystemWindows="true"> <ImageView  android:id="@+id/ivWave"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:layout_margin="5dp"  android:src="@drawable/wave" /> <ImageView  android:id="@+id/ivLightbeam"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:src="@drawable/light_beam" /></FrameLayout>

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval"> <size  android:width="500dp"  android:height="500dp" /> <gradient  android:endColor="#AAAAAAAA"  android:startColor="#00000000"  android:type="sweep"  /></shape>

<layer-list xmlns:android="http://schemas.android.com/apk/res/android"> <item>  <!--最外层圆圈-->  <shape android:shape="oval">   <solid android:color="#10FFFFFF" />   <size    android:width="600dp"    android:height="600dp" />   <stroke    android:color="#10B8B8B8"    android:dashWidth="1dp" />  </shape> </item> <item  android:bottom="100dp"  android:left="100dp"  android:right="100dp"  android:top="100dp">  <!--最中间层圆圈-->  <shape android:shape="oval">   <solid android:color="#1CFFFFFF" />   <stroke    android:color="#1CB8B8B8"    android:dashWidth="1dp" />  </shape> </item> <item  android:bottom="200dp"  android:left="200dp"  android:right="200dp"  android:top="200dp">  <!--最中心圆圈-->  <shape android:shape="oval">   <solid android:color="#2CFFFFFF" />   <stroke    android:color="#2CB8B8B8"    android:dashWidth="1dp" />  </shape> </item></layer-list>