Xamarin.Android implements the function of making calls

Table of Contents

• 1. Description
• 2. Realization of effect
• 3. Implementation process
• • 3.1 Manifest configuration
  • 3.2 Interface settings
  • 3.3 String resources
  • 3.4 Implementation
• 4. Code download
• 5. Reference materials

1. Description

The function of making a phone call is realized through Xamarin.Android. VS2019 Community Edition

2. Effect realization

3. Implementation process

3.1 Manifest Configuration

There must be permission settings for making calls.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.1" package="com.companyname.dialdemo" android:installLocation= "auto">
<uses-sdk android:minSdkVersion="24" android:targetSdkVersion="30" />
<application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme= "@style/AppTheme"></application>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CALL_PHONE" /> <!--Permission application for making calls-->
\t
<queries>
<intent>
<action android:name="android.intent.action.DIAL" /> <!--Refer to Android's dial-up function-->
<data android:scheme="tel" />
</intent>
</queries>
</manifest>

3.2 Interface Settings

layout_main.xml file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:layout_width="158.0dp"
        android:layout_height="wrap_content"
        android:id="@ + id/editText1"
        android:inputType="text" />

        <Button
        android:text="@string/dial_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:minWidth="25px"
        android:minHeight="25px"
        android:id="@ + id/button1"
        android:layout_below="@id/editText1"
        />

    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:minWidth="25px"
        android:minHeight="25px"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/button1"
        android:id="@ + id/coordinatorLayout1"
        android:layout_centerVertical="true"
        android:layout_alignParentBottom="true"/>


</RelativeLayout>

3.3 String resources

The content of String.xml is as follows:

<resources>
    <string name="app_name">DialDemo</string>
    <string name="action_settings">Settings</string>
  <string name="permission_call_phone">Do you agree to grant the permission to make calls</string>
  <string name="ok">Consent Granted</string>
  <string name="permission_available_call">I have agreed to the authorization</string>
  <string name="permissions_not_granted">Failed to authorize</string>
  <string name="dial_btn">Call the phone</string>
</resources>

3.4 Specific implementation

using Android;
using Android. App;
using Android. Content;
using Android.Content.PM;
using Android. OS;
using Android. Views;
using Android. Widget;
using AndroidX.AppCompat.App;
using AndroidX. CoordinatorLayout. Widget;
using AndroidX. Core. App;
using Google.Android.Material.Snackbar;
using System;

namespace DialDemo
{<!-- -->
    [Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]
    public class MainActivity : AppCompatActivity
    {<!-- -->

        private Button dialBtn;
        private EditText phoneNo;
        private int REQUEST_LOCATION = 1;
        private CoordinatorLayout coordinatorLayout;

        protected override void OnCreate(Bundle savedInstanceState)
        {<!-- -->
            base.OnCreate(savedInstanceState);
            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            // Set our view from the "main" layout resource
            SetContentView(Resource. Layout. activity_main);

            dialBtn = FindViewById<Button>(Resource.Id.button1);
            phoneNo = FindViewById<EditText>(Resource.Id.editText1);

            coordinatorLayout = FindViewById<CoordinatorLayout>(Resource.Id.coordinatorLayout1);

            dialBtn.Click += DialBtn_Click;

        }



        //Determine permissions and authorize
        public void checkAndGetPermission()
        {<!-- -->
            if (ActivityCompat. ShouldShowRequestPermissionRationale(this, Manifest. Permission. CallPhone))
            {<!-- -->
                
                var requiredPermissions = new String[] {<!-- --> Manifest. Permission. CallPhone };
                Snackbar. Make(coordinatorLayout,
                               Resource.String.permission_call_phone,
                               Snackbar. Length Indefinite)
                        .SetAction(Resource.String.ok,
                                   new Action<View>(delegate (View obj)
                                   {<!-- -->
                                       ActivityCompat. RequestPermissions(this, requiredPermissions, REQUEST_LOCATION);
                                   }
                        )
                ).Show();
            }
            else
            {<!-- -->
                ActivityCompat.RequestPermissions(this, new String[] {<!-- --> Manifest.Permission.CallPhone }, REQUEST_LOCATION);
            }
        }



//Permission judgment here
        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
        {<!-- -->
            if (requestCode == REQUEST_LOCATION)
            {<!-- -->
                if ((grantResults.Length == 1) & amp; & amp; (grantResults[0] == Permission.Granted)) //If you agree to the authorization
                {<!-- -->
                    Snackbar.Make(coordinatorLayout, Resource.String.permission_available_call, Snackbar.LengthShort).Show();
                    call();
                }
                else //If you do not agree to the authorization
                {<!-- -->
                    Snackbar.Make(coordinatorLayout, Resource.String.permissions_not_granted, Snackbar.LengthShort).Show();
                }
            }
            else
            {<!-- -->
                base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
            }
        }

        private void DialBtn_Click(object sender, System.EventArgs e)
        {<!-- -->
            checkAndGetPermission();
        }

        //Specific call method
        private void call()
        {<!-- -->
            try
            {<!-- -->
                var intent = new Intent(Intent. ActionCall);
                intent.SetData(Android.Net.Uri.Parse("tel:" + phoneNo.Text));
                StartActivity(intent);
            }
            catch (Exception e1)
            {<!-- -->
                Toast.MakeText(this, e1.Message, ToastLength.Long).Show();
            }
        }
            

        
    }
}

4. Code download

code download

5. Reference

1. Use of Snackbar
2. Contents of permissions in Xamarin official website