system_alert_window

A flutter plugin to show Truecaller like overlay window, over all other apps along with callback events.

Android

Demo

1. Clip of example app and 2. Working of button click in the background

      

Application Class

JAVA (Application.java)

  import android.os.Bundle;
  import in.jvapps.system_alert_window.SystemAlertWindowPlugin;
  import io.flutter.app.FlutterApplication;
  import io.flutter.plugin.common.PluginRegistry;
  import io.flutter.plugins.GeneratedPluginRegistrant;

  public class Application extends FlutterApplication implements PluginRegistry.PluginRegistrantCallback {

      @Override
      public void onCreate() {
          super.onCreate();
          //This is required as we are using background channel for dispatching click events
          SystemAlertWindowPlugin.setPluginRegistrant(this);
      }

      @Override
      public void registerWith(PluginRegistry pluginRegistry) {
          GeneratedPluginRegistrant.registerWith(pluginRegistry);
      }

  }

KOTLIN (Application.kt)

  import `in`.jvapps.system_alert_window.SystemAlertWindowPlugin
  import io.flutter.app.FlutterApplication
  import io.flutter.plugin.common.PluginRegistry
  import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback
  class Application : FlutterApplication(), PluginRegistrantCallback {
      override fun onCreate() {
          super.onCreate()
          SystemAlertWindowPlugin.setPluginRegistrant(this)
      }

     override fun registerWith(registry: PluginRegistry) {
        SystemAlertWindowPlugin.registerWith(registry.registrarFor("in.jvapps.system_alert_window"));
     }
  }

Manifest

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


      <application
          //Linking the previously added application class
          android:name=".Application"
          android:label="system_alert_window_example"
          android:icon="@mipmap/ic_launcher">

Android 10 & below

Uses 'draw on top' permission and displays it as a overlay window

Android 11 & above

Uses Android Bubble APIs to show the overlay window.

IOS

Displays as a notification in the notification center [Help Needed]

Example

Show the overlay

  SystemWindowHeader header = SystemWindowHeader(
      title: SystemWindowText(text: "Incoming Call", fontSize: 10, textColor: Colors.black45),
      padding: SystemWindowPadding.setSymmetricPadding(12, 12),
      subTitle: SystemWindowText(text: "9898989899", fontSize: 14, fontWeight: FontWeight.BOLD, textColor: Colors.black87),
      decoration: SystemWindowDecoration(startColor: Colors.grey[100]),
      button: SystemWindowButton(text: SystemWindowText(text: "Personal", fontSize: 10, textColor: Colors.black45), tag: "personal_btn"),
      buttonPosition: ButtonPosition.TRAILING);
        );
        
  SystemWindowFooter footer = SystemWindowFooter(
      buttons: [
        SystemWindowButton(
          text: SystemWindowText(text: "Simple button", fontSize: 12, textColor: Color.fromRGBO(250, 139, 97, 1)),
          tag: "simple_button", //useful to identify button click event
          padding: SystemWindowPadding(left: 10, right: 10, bottom: 10, top: 10),
          width: 0,
          height: SystemWindowButton.WRAP_CONTENT,
          decoration: SystemWindowDecoration(
          startColor: Colors.white, endColor: Colors.white, borderWidth: 0, borderRadius: 0.0),
         ),
        SystemWindowButton(
          text: SystemWindowText(text: "Focus button", fontSize: 12, textColor: Colors.white),
          tag: "focus_button",
          width: 0,
          padding: SystemWindowPadding(left: 10, right: 10, bottom: 10, top: 10),
          height: SystemWindowButton.WRAP_CONTENT,
          decoration: SystemWindowDecoration(
          startColor: Color.fromRGBO(250, 139, 97, 1), endColor: Color.fromRGBO(247, 28, 88, 1), borderWidth: 0, borderRadius: 30.0),
         )
      ],
      padding: SystemWindowPadding(left: 16, right: 16, bottom: 12),
      decoration: SystemWindowDecoration(startColor: Colors.white),
      buttonsPosition: ButtonPosition.CENTER);
      
  SystemWindowBody body = SystemWindowBody(
          rows: [
            EachRow(
              columns: [
                EachColumn(
                  text: SystemWindowText(text: "Some body", fontSize: 12, textColor: Colors.black45),
                ),
              ],
              gravity: ContentGravity.CENTER,
            ),
          ],
          padding: SystemWindowPadding(left: 16, right: 16, bottom: 12, top: 12),
        );

  SystemAlertWindow.showSystemWindow(
      height: 230,
      header: header,
      body: body,
      footer: footer,
      margin: SystemWindowMargin(left: 8, right: 8, top: 100, bottom: 0),
      gravity: SystemWindowGravity.TOP);

Register for onClick events (button click)

  SystemAlertWindow.registerOnClickListener(callBackFunction);

  ///
  /// As this callback function is called from background, it should be declared on the parent level
  /// Whenever a button is clicked, this method will be invoked with a tag (As tag is unique for every button, it helps in identifying the button).
  /// You can check for the tag value and perform the relevant action for the button click
  ///
  void callBackFunction(String tag) {
    switch(tag){
      case "simple_button":
        print("Simple button has been clicked");
        break;
      case "focus_button":
        print("Focus button has been clicked");
        break;
      case "personal_btn":
        print("Personal button has been clicked");
        break;
      default:
        print("OnClick event of $tag");
    }
  }

Close the overlay

  SystemAlertWindow.closeSystemWindow();

Isolate communication

Use this snippet, if you want the callbacks on your main thread, instead of handling them in an isolate (like mentioned above)

Create an isolate_manager.dart

import 'dart:isolate';

import 'dart:ui';

class IsolateManager{

  static const FOREGROUND_PORT_NAME = "foreground_port";

  static SendPort lookupPortByName() {
    return IsolateNameServer.lookupPortByName(FOREGROUND_PORT_NAME);
  }

  static bool registerPortWithName(SendPort port) {
    assert(port != null, "'port' cannot be null.");
    removePortNameMapping(FOREGROUND_PORT_NAME);
    return IsolateNameServer.registerPortWithName(port, FOREGROUND_PORT_NAME);
  }

  static bool removePortNameMapping(String name) {
    assert(name != null, "'name' cannot be null.");
    return IsolateNameServer.removePortNameMapping(name);
  }

}

While initializing system alert window in your code

    await SystemAlertWindow.checkPermissions;
    ReceivePort _port = ReceivePort();
    IsolateManager.registerPortWithName(_port.sendPort);
    _port.listen((dynamic callBackData) {
      String tag= callBackData[0];
      switch (tag) {
        case "personal_btn":
          print("Personal button click : Do what ever you want here. This is inside your application scope");
          break;
        case "simple_button":
          print("Simple button click : Do what ever you want here. This is inside your application scope");
          break;
        case "focus_button":
          print("Focus button click : Do what ever you want here. This is inside your application scope");
          break;
      }
    });
    SystemAlertWindow.registerOnClickListener(callBackFunction);

Now the callBackFunction should looks like

bool callBackFunction(String tag) {
  print("Got tag " + tag);
  SendPort port = IsolateManager.lookupPortByName();
  port.send([tag]);
  return true;
}