How to open an application from a Flutter app?

I suggest you to use url_launcher dart package.

In this way you can use all url schemas to open (phone, sms, and even maps as in your case).

In order to open Google Maps either in Android and iOS you could use the general Android Maps URI schema as suggested by Hemanth Raj.

_openMap() async {
    const url = 'https://www.google.com/maps/search/?api=1&query=52.32,4.917';
    if (await canLaunch(url)) {
      await launch(url);
    } else {
      throw 'Could not launch $url';
    }
  }

If you want to give a choice on Android you could use the general geo: URI schema.

If you want specifically open iOS Maps API you can use Cupertino Maps URI schema.

If you choose to distinguish between Android and iOS (not using Google Maps Api schema for all platform) you have to do it also in your open map call in a way like this:

_openMap() async {
    // Android
    const url = 'geo:52.32,4.917';
    if (await canLaunch(url)) {
      await launch(url);
    } else {
      // iOS
      const url = 'http://maps.apple.com/?ll=52.32,4.917';
      if (await canLaunch(url)) {
        await launch(url);
      } else {
        throw 'Could not launch $url';
      }
    }
  }

Or you can check the OS at runtime with dart.io library Platform class:

import 'dart:io';

_openMap() async {
    // Android
    var url = 'geo:52.32,4.917';
    if (Platform.isIOS) {
      // iOS
      url = 'http://maps.apple.com/?ll=52.32,4.917';
    }
    if (await canLaunch(url)) {
      await launch(url);
    } else {
      throw 'Could not launch $url';
    }
  }

Now that I finished hosekeeping (the real one... not some code refactoring... ^^') I can finish my answer.

As I tell you at the beginning with url_launcher you can use all URI Schemas in order to call, send sms, send e-mail etc.

Here some code to do that:

_sendMail() async {
    // Android and iOS
    const uri = 'mailto:[email protected]?subject=Greetings&body=Hello%20World';
    if (await canLaunch(uri)) {
      await launch(uri);
    } else {
    throw 'Could not launch $uri';
    }
  }

  _callMe() async {
    // Android
    const uri = 'tel:+1 222 060 888';
    if (await canLaunch(uri)) {
      await launch(uri);
    } else {
      // iOS
      const uri = 'tel:001-22-060-888';
      if (await canLaunch(uri)) {
        await launch(uri);
      } else {
        throw 'Could not launch $uri';
      }
    }
  }

  _textMe() async {
    // Android
    const uri = 'sms:+39 349 060 888';
    if (await canLaunch(uri)) {
      await launch(uri);
    } else {
      // iOS
      const uri = 'sms:0039-222-060-888';
      if (await canLaunch(uri)) {
        await launch(uri);
      } else {
        throw 'Could not launch $uri';
      }
    }
  }

Even if URI schema should be standards (RFC) sometimes the authority and path parts of them could differ between frameworks (Android or iOS).

So here I manage the different OSes with exception but, you could do it better with dart.io library Platform class:

import 'dart:io'

and then in code:

if (Platform.isAndroid) {

} else if (Platform.isIOS) {

}

I suggest you always test them in both environments.

You can check the Android and iOS schema documenation here:

• Android
• iOS

If you wanna something similar to startActivity in Android (but that works only for Android platform) you can use the dart package android_intent.

For iOS use, no browser involved, directly to apps:

//waze 
canLaunch("waze://") 
launch("waze://?ll=${latitude},${longitude}&navigate=yes"); 
//gmaps 
canLaunch("comgooglemaps://") 
launch("comgooglemaps://?saddr=${latitude},${longitude}&directionsmode=driving")

What you need to do is to add to Info.plist:

<key>LSApplicationQueriesSchemes</key>  
<array>         
  <string>comgooglemaps</string>        
  <string>waze</string>     
</array>

You can just use the url_launcher plugin to open maps. It launches map if installed or falls back to open the map on a browser.

Example:

import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart';

void main() {
  runApp(new Scaffold(
    body: new Center(
      child: new RaisedButton(
        onPressed: _launchURL,
        child: new Text('Launch Maps'),
      ),
    ),
  ));
}

_launchMaps() async {
  const url = "https://www.google.com/maps/search/?api=1&query=LATITUDE,LONGITUDE,17&query_place_id=PLACE_ID";
  if (await canLaunch(url)) {
    await launch(url);
  } else {
    throw 'Could not launch Maps';
  }
}

Hope that helps!