Detailed explanation of simple usage examples of android WindowManager

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:andro
    xmlns:tools="/tools">
    <uses-permission android:name=".SYSTEM_ALERT_WINDOW" />
    <uses-permission android:name=".SYSTEM_OVERLAY_WINDOW" />
    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.App0"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="" />
                <category android:name="" />
            </intent-filter>
        </activity>
    </application>
</manifest>

package .app0;
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public class MainActivity extends AppCompatActivity {
    private static Context context;
    private Button button;
    private View imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        (savedInstanceState);
        setContentView(.activity_main);
        context = getApplication().getApplicationContext();
        button = findViewById(.btn1);
        imageView = (context).inflate(,null);
        (listener);
    }
    private  listener =  new (){
        @Override
        public void onClick(View v) {
             layoutParams = new ();
//             = PixelFormat.RGBA_8888;
             = .FLAG_NOT_FOCUSABLE;
//             = 200;
//             = 200;
//             = .TYPE_APPLICATION_OVERLAY;
//             =  | ;
             = 30;
             = 40;
            WindowManager windowManager = getWindowManager();
            (imageView,layoutParams);
        }
    };
    public static Context getContext(){
        return context;
    }
}