Display Alert message in Android

How to display Alert message in Android Application?

Here is a sample code of an application that explains how you can display a simple Alert message in your Android application. The below code can be put on a button click event or wherever you would like it to popup.

             

DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() { /*DialogInterface called while setting the AlertDialog Buttons */

    public void onClick(DialogInterface dialog, int which) {
        

    //Here you can perform functions of Alert Dialog Buttons as shown

     switch (which){
        case DialogInterface.BUTTON_POSITIVE:
         //Yes button clicked
        break;


        case DialogInterface.BUTTON_NEGATIVE:
//No button clicked
        break;
        }

     }

 };

       

 AlertDialog.Builder builder = new AlertDialog.Builder(this);

 builder.setTitle("Alert Dialog");// Set the Title of Alert Dialog

 builder.setMessage("Are you sure?")
 .setPositiveButton("Yes",dialogClickListener)

.setNegativeButton("No", dialogClickListener).show();/* Setting the Alert message with buttons Yes and No */                                                     

//You can also set the icon of Alert Dialog using this code

builder.setIcon(R.drawable.icon);

Enable/Disable WiFi in Android Application

Turn WiFi enable/disable using WIFI Manager in Android Application

Using the Wifi Manager class you can get access to Wifi to change its state.

In this Application, as shown TextView shows the WiFi status.

Here is how you can programmatically access Wifi in Android Application :-

import android.app.Activity;

import android.content.Context;

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

import android.net.wifi.ScanResult;

import android.net.wifi.WifiConfiguration;

import android.net.wifi.WifiInfo;

import android.net.wifi.WifiManager;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ImageSwitcher;

import android.widget.TextView;

public class ConnectivitymanagerActivity extends Activity implements OnClickListener {

       Button TurnWifion, TurnWifioff;

       TextView wifistatus;

       WifiManager wifi;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

   

       

        TurnWifion = (Button)findViewById(R.id.button1);

        TurnWifioff = (Button)findViewById(R.id.button2);

        WifiStatus = (TextView)findViewById(R.id.textView1);

        // Getting the WiFi Services

        wifi=(WifiManager)getSystemService(Context.WIFI_SERVICE);

        //Checking whether  Wifi is on or off

        if(wifi.isWifiEnabled())

        {

          wifistatus.setText("Connected");//If WiFi is on, enable "Turn WiFi off" button.

          TurnWifioff.setEnabled(true);

          TurnWifion.setEnabled(false);

                    

         }

         else

         {

          wifistatus.setText("Disconnected");//If WiFi is off, enable "Turn WiFi on" button.

                     Turnwifion.setEnabled(true);

                     TurnWifioff.setEnabled(false); 

         }

        Turnwifion.setOnClickListener(this);

        Turnwifioff.setOnClickListener(this);     

     }

       public void onClick(View v) {

              // TODO Auto-generated method stub

             

              if(Turnwifion.isPressed())    //If "Turn WiFi on" button is Pressed

              {                    

                     wifi.setWifiEnabled(true);// Enabling WiFi

                     Turnwifioff.setEnabled(true);

                     Turnwifion.setEnabled(false);

                     wifistatus.setText("Connected");

              }

               if(Turnwifioff.isPressed())   //If "Turn WiFi off" button is Pressed

              {

                     wifi.setWifiEnabled(false); //Disabling WiFi

                     Turnwifion.setEnabled(true);

                     Tunwifioff.setEnabled(false);

                     wifistatus.setText("Disconnected");

              }

       }

}

Permissions : You need to declare the following permissions in AndroidManifest.xml  to let Wifi Manager class access the WiFi.

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>

<uses-permission android:name="android.permission.UPDATE_DEVICE_STATS" />

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