android 实现悬浮窗功能

1. 在 AndroidManifest.xml 文件中添加权限：

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

2. 创建一个服务类，继承自 Service：

public class FloatingService extends Service {

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        createFloatingWindow();
        return super.onStartCommand(intent, flags, startId);
    }

    private void createFloatingWindow() {
        // 创建悬浮窗
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        // 关闭悬浮窗
    }
}

3. 在 onCreate() 方法中启动服务：

public void onCreate() {
    super.onCreate();
    Intent intent = new Intent(this, FloatingService.class);
    startService(intent);
}

4. 在 createFloatingWindow() 方法中创建悬浮窗：

private void createFloatingWindow() {
    // 初始化 WindowManager
    WindowManager windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);

    // 创建悬浮窗布局
    View floatingView = LayoutInflater.from(this).inflate(R.layout.floating_window, null);

    // 设置悬浮窗布局参数
    WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams();
    layoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
    layoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
    layoutParams.type = WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;
    layoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
    layoutParams.format = PixelFormat.TRANSLUCENT;
    layoutParams.gravity = Gravity.CENTER;

    // 添加悬浮窗布局到 WindowManager 中
    windowManager.addView(floatingView, layoutParams);
}

5. 在 onDestroy() 方法中关闭悬浮窗：

@Override
public void onDestroy() {
    super.onDestroy();
    WindowManager windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
    windowManager.removeView(floatingView);
}

6. 创建悬浮窗布局文件 floating_window.xml：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:background="#FF0000"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <TextView
        android:text="悬浮窗"
        android:textColor="#FFFFFF"
        android:textSize="20sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

7. 运行程序即可看到悬浮窗。