【Android】创建一个可以在屏幕上拖动的悬浮窗

项目需求

在界面上创建一个悬浮窗，可以自由的移动这个悬浮窗

需求解决

1.添加权限

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>

2.请求权限
从 Android 6.0 (API 23) 开始，应用需要动态请求显示悬浮窗的权限。例如，可以在 MainActivity 中请求权限：

public class MainActivity extends AppCompatActivity {private static final int OVERLAY_PERMISSION_REQUEST_CODE = 1234;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (!Settings.canDrawOverlays(this)) {Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,Uri.parse("package:" + getPackageName()));startActivityForResult(intent, OVERLAY_PERMISSION_REQUEST_CODE);} else {// 权限已经授予，启动悬浮窗服务startFloatingWindowService();}} else {// 系统版本低于6.0，不需要请求权限，直接启动悬浮窗服务startFloatingWindowService();}}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (requestCode == OVERLAY_PERMISSION_REQUEST_CODE) {if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (Settings.canDrawOverlays(this)) {// 权限授予，启动悬浮窗服务startFloatingWindowService();} else {// 权限未授予，提示用户// TODO: 处理权限未授予情况}}}}private void startFloatingWindowService() {Intent intent = new Intent(MainActivity.this, FloatingWindowService.class);startService(intent);}
}

3. 创建悬浮窗服务
   实现一个服务（FloatingWindowService），它将负责创建和管理悬浮窗视图。

public class FloatingWindowService extends Service {private WindowManager windowManager;private View floatingView;public FloatingWindowService() {}@Nullable@Overridepublic IBinder onBind(Intent intent) {return null;}@Overridepublic void onCreate() {super.onCreate();windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);floatingView = inflater.inflate(R.layout.floating_window, null);final WindowManager.LayoutParams params = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT,WindowManager.LayoutParams.WRAP_CONTENT,WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,PixelFormat.TRANSLUCENT);// 初始位置params.x = 0;params.y = 0;windowManager.addView(floatingView, params);// 使悬浮窗可拖动floatingView.setOnTouchListener(new View.OnTouchListener() {private int initialX;private int initialY;private float initialTouchX;private float initialTouchY;@Overridepublic boolean onTouch(View v, MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:initialX = params.x;initialY = params.y;initialTouchX = event.getRawX();initialTouchY = event.getRawY();return true;case MotionEvent.ACTION_MOVE:params.x = initialX + (int) (event.getRawX() - initialTouchX);params.y = initialY + (int) (event.getRawY() - initialTouchY);windowManager.updateViewLayout(floatingView, params);return true;}return false;}});}@Overridepublic void onDestroy() {super.onDestroy();if (floatingView != null) windowManager.removeView(floatingView);}
}

4. 创建悬浮窗布局
   在 res/layout 目录下创建一个名为 floating_window.xml 的布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="wrap_content"android:layout_height="wrap_content"android:background="#80000000"android:orientation="vertical"android:padding="10dp"><TextViewandroid:id="@+id/textView"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="CSDN -> 我又来搬代码了"android:textColor="#FFFFFF" /></LinearLayout>

注意：要记得在注册清单文件注册服务

        <serviceandroid:name=".service.FloatingWindowService"android:enabled="true"android:exported="true" />

实现效果

这个可以随意拖动。