如何在java中使用system_alert_窗口弹出窗口

我需要让我的应用程序优于其他应用程序，我尝试获得如下所示的

SYSTEM\u ALERT\u WINDOW

权限

public class excessiveusageactivity extends AppCompatActivity {

    static final int REQUEST_OVERLAY_PERMISSION = 1; //request code
    TextView result;

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        result = findViewById(R.id.result);
     if (requestCode == REQUEST_OVERLAY_PERMISSION) {
         if (Settings.canDrawOverlays(this)) {
             Toast permissionok = Toast.makeText(this, "permission granted!", Toast.LENGTH_SHORT);
             permissionok.show();
             //permission granted do stuff
             result.setText("yay");
         }else{
             Toast permissionnotgrantedtoast = Toast.makeText(this,"permission request failed, try again!", Toast.LENGTH_LONG);
             permissionnotgrantedtoast.show();
             //permission not granted
             result.setText("not granted");
         }
     }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_excessiveusageactivity);

        if(
                Settings.canDrawOverlays(this)
        ) {
            // ask for overlay permission
            Intent requestoverlaypermissionintent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
                    Uri.parse("package:" + getPackageName()));
            startActivityForResult(requestoverlaypermissionintent, REQUEST_OVERLAY_PERMISSION);
            result.setText("here");
        }
    }
}

我从用户Jayman Jani那里得到了这个代码

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当用户连续使用某个应用程序X分钟/小时时，我希望创建一个自定义系统警报弹出窗口，但我似乎找不到有关如何设置此弹出窗口的任何信息。我对这一切都很陌生，所以如果有人能一步一步地解释，那就太好了。谢谢大家!

当前代码有什么问题？我不知道如何使用权限。如何设置弹出窗口？