Implementation of simple floating frame in WindowManager

Reference resources ：

permission denied for window type 2003

WindowManager( Window management service )

10.7 WindowManager( Window management service )

jurisdiction ：

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

// Check authority 
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    
    if (!Settings.canDrawOverlays(this)) {
    
        // start-up Activity Let the user authorize 
        Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
        startActivity(intent);
        return;
    }
}

Definition service ：

import android.annotation.SuppressLint;
import android.app.ActivityManager;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.PixelFormat;
import android.os.Build;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

import java.util.ArrayList;
import java.util.List;

public class MainService extends Service {
    

    private boolean isAdded = false; //  Whether the suspension window has been added 
    public static final int OPERATION_SHOW = 100;
    public static final int OPERATION_HIDE = 101;
    private static final int HANDLE_CHECK_ACTIVITY = 200;
    public static final String OPERATION = "operation";
    private WindowManager mWindowManager;
    private WindowManager.LayoutParams mLayoutParams;
    private Button btnView;
    private ActivityManager mActivityManager;
    private List<String> homeList; //  List of desktop application package names 

    // Define an update interface Handler
    @SuppressLint("HandlerLeak")
    private final Handler mHandler = new Handler() {
    
        @Override
        public void handleMessage(Message msg) {
    
            switch (msg.what) {
    
                case HANDLE_CHECK_ACTIVITY:
                    if (isHome()) {
    
                        if (!isAdded) {
    
                            mWindowManager.addView(btnView, mLayoutParams);
                            isAdded = true;
                            new Thread(new Runnable() {
    
                                public void run() {
    
                                    for (int i = 0; i < 10; i++) {
    
                                        try {
    
                                            Thread.sleep(1000);
                                        } catch (InterruptedException e) {
    
                                            e.printStackTrace();
                                        }
                                        Message m = new Message();
                                        m.what = 2;
                                        mHandler.sendMessage(m);
                                    }
                                }
                            }).start();
                        }
                    } else {
    
                        if (isAdded) {
    
                            mWindowManager.removeView(btnView);
                            isAdded = false;
                        }
                    }
                    mHandler.sendEmptyMessageDelayed(HANDLE_CHECK_ACTIVITY, 0);
                    break;
            }
        }
    };

    @Override
    public void onCreate() {
    
        super.onCreate();
        homeList = getHomes();
        createWindowView();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
    
        int operation = intent.getIntExtra(OPERATION, OPERATION_SHOW);
        switch (operation) {
    
            case OPERATION_SHOW:
                mHandler.removeMessages(HANDLE_CHECK_ACTIVITY);
                mHandler.sendEmptyMessage(HANDLE_CHECK_ACTIVITY);
                break;
            case OPERATION_HIDE:
                mHandler.removeMessages(HANDLE_CHECK_ACTIVITY);
                break;
        }
        return super.onStartCommand(intent, flags, startId);
    }

    //  Define a method to create a hover box :
    @SuppressLint({
    "ClickableViewAccessibility", "RtlHardcoded"})
    private void createWindowView() {
    
        btnView = new Button(getApplicationContext());
        btnView.setBackgroundResource(R.mipmap.ic_launcher);
        mWindowManager = (WindowManager) getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
        mLayoutParams = new WindowManager.LayoutParams();

        //  Set up Window Type
        //【 Be careful 】 Check version , Pay attention to when type by TYPE_APPLICATION_OVERLAY when , Spread the active windows , But below the critical system window , Such as status bar or IME
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    
            mLayoutParams.type = WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;
        } else {
    
            mLayoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
        }


        //  Set the suspension box to be untouchable 
        mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
        //  The suspended window cannot be touched , Do not accept any events , At the same time, it does not affect the subsequent event response 
        mLayoutParams.format = PixelFormat.RGBA_8888;
        //  Set the width and height of the floating box 
        mLayoutParams.width = 200;
        mLayoutParams.height = 200;
        mLayoutParams.gravity = Gravity.LEFT | Gravity.TOP;
        mLayoutParams.x = 200;
        mLayoutParams.y = 0;
        //  Set the... Of the hover box Touch monitor 
        btnView.setOnTouchListener(new View.OnTouchListener() {
    
            // Save the variable of the last position of the hover box 
            int lastX, lastY;
            int paramX, paramY;

            @Override
            public boolean onTouch(View v, MotionEvent event) {
    
                switch (event.getAction()) {
    
                    case MotionEvent.ACTION_DOWN:
                        lastX = (int) event.getRawX();
                        lastY = (int) event.getRawY();
                        paramX = mLayoutParams.x;
                        paramY = mLayoutParams.y;
                        break;
                    case MotionEvent.ACTION_MOVE:
                        int dx = (int) event.getRawX() - lastX;
                        int dy = (int) event.getRawY() - lastY;
                        mLayoutParams.x = paramX + dx;
                        mLayoutParams.y = paramY + dy;
                        //  Update the position of the suspended window 
                        mWindowManager.updateViewLayout(btnView, mLayoutParams);
                        break;
                }
                return true;
            }
        });
        mWindowManager.addView(btnView, mLayoutParams);
        isAdded = true;
    }

    /** *  Determine whether the current interface is a desktop  */
    public boolean isHome() {
    
        if (mActivityManager == null) {
    
            mActivityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
        }
        List<ActivityManager.RunningTaskInfo> rti = mActivityManager.getRunningTasks(1);
        return homeList.contains(rti.get(0).topActivity.getPackageName());
    }

    /** *  Get the application package name of the application belonging to the desktop  * * @return  Returns a list of strings containing all package names  */
    private List<String> getHomes() {
    
        List<String> names = new ArrayList<String>();
        PackageManager packageManager = this.getPackageManager();
        //  attribute 
        Intent intent = new Intent(Intent.ACTION_MAIN);
        intent.addCategory(Intent.CATEGORY_HOME);
        @SuppressLint("QueryPermissionsNeeded")
        List<ResolveInfo> resolveInfo = packageManager.queryIntentActivities(intent,
                PackageManager.MATCH_DEFAULT_ONLY);
        for (ResolveInfo ri : resolveInfo) {
    
            names.add(ri.activityInfo.packageName);
        }
        return names;
    }

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

start-up service ：

Intent mIntent = new Intent(MainActivity5.this, MainService.class);
mIntent.putExtra(MainService.OPERATION, MainService.OPERATION_SHOW);
startService(mIntent);
Toast.makeText(MainActivity5.this, " The hover box has been opened ~", Toast.LENGTH_SHORT).show();