Android Check Network Connection

You may be building an application which requires an Internet connection. It is very important to detect the internet connection before the application starts working so that to prevent the application from raising exceptions. Here I am explaining how to achieve the goal.

First you need to include the permissions in the Manifest file after the <application> tag.

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

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

After including the permissions, just add a few lines of code where you want to detect the internet connection.

ConnectivityManager cm = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo[] arrar_ni = cm.getAllNetworkInfo();

        for (NetworkInfo ni : arrar_ni)

        {

            if (ni.getTypeName().equalsIgnoreCase("WIFI"))

            {

                if (ni.isConnected())

                {

                    Toast.makeText(this, "WiFi Available", Toast.LENGTH_LONG).show();

                } else

                {

                    Toast.makeText(this, "WiFi Not Available", Toast.LENGTH_LONG).show();

                }

            }

            if (ni.getTypeName().equalsIgnoreCase("MOBILE"))

            {

                if (ni.isConnected())

                {

                    Toast.makeText(this, "Mobile Available", Toast.LENGTH_LONG).show();

                } else

                {

                    Toast.makeText(this, "Mobile Not Available", Toast.LENGTH_LONG).show();

                }

            }

        }

The above code will generate Toast displaying the availability and type of internet connection. You can replace the Toast statements with your code according to the requirement of your application.

Android Date Picker

So here we are with an example to demonstrate how to implement Date Picker in your Android application.

First we need to create a TextBox to display the date and a button to trigger the Date Picker Dialog Box.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context="com.codingredefined.datepicker.MainActivity" >

    <TextView

        android:id="@+id/displayDate"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="@string/hello_world" />

    <Button 

        android:id="@+id/pickDate"

        android:layout_below="@+id/displayDate"

        android:paddingTop="5dp"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Pick Date" />

</RelativeLayout>

After creating the layout for our application we need to add following code in our MainActivity class.

package com.codingredefined.datepicker;

import java.util.Calendar;

import android.support.v7.app.ActionBarActivity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity
{

private TextView displayDate;
private int mday, mmonth, myear;
static final int DATE_DIALOG_ID = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        displayDate = (TextView)findViewById(R.id.displayDate);
        Button pickDate = (Button)findViewById(R.id.pickDate);
       
        pickDate.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub

showDialog(DATE_DIALOG_ID);

}
});
   
        final Calendar c = Calendar.getInstance();
        myear = c.get(Calendar.YEAR);
        mmonth = c.get(Calendar.MONTH);
        mday = c.get(Calendar.DAY_OF_MONTH);
        updateDisplay();
       
    }

    @Override
    protected Dialog onCreateDialog(int id)
    {
    switch(id)
    {
    case DATE_DIALOG_ID:
    return new DatePickerDialog(this, dateSetListener, myear, mmonth, mday);
    }
    return null;
    }
   
    protected void onPrepareDialog(int id, Dialog dialog)
    {
    switch(id)
    {
    case DATE_DIALOG_ID:
    ((DatePickerDialog)dialog).updateDate(myear, mmonth, mday);
    break;
    }
    }
   
    private void updateDisplay()
    {
    displayDate.setText(new StringBuilder().append(mmonth +1).append("-").append(mday).append("-").append(myear).append(" "));
    }
   
    private DatePickerDialog.OnDateSetListener dateSetListener = new DatePickerDialog.OnDateSetListener() {

@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
// TODO Auto-generated method stub

myear = year;
mmonth = monthOfYear;
mday = dayOfMonth;
updateDisplay();

}
};
   
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Save the code and run.

Android Broadcast Receiver

Hey, in this tutorial we will learn to implement Broadcast Receiver in your Android app. Broadcast Receivers are implemented to respond to the messages broadcasted by the system or by other applications.

First create a button which will trigger a broadcast from our application.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.codingredefined.broadcastreceiver.MainActivity" >

    <Button
        android:id="@+id/btnStartService"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Broadcast Intent"
        android:onClick="broadcastIntent"
        />

</RelativeLayout>

After creating the button make changes in the MainActivity.java file.

package com.codingredefined.broadcastreceiver;

import android.support.v7.app.ActionBarActivity;

import android.content.Intent;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

public class MainActivity extends ActionBarActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.main, menu);

        return true;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        // Handle action bar item clicks here. The action bar will

        // automatically handle clicks on the Home/Up button, so long

        // as you specify a parent activity in AndroidManifest.xml.

        int id = item.getItemId();

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

    

    //broadcast a custom intent

    public void broadcastIntent(View view)

    {

    Intent intent= new Intent();

    intent.setAction("com.codingredefined.CUSTOM_INTENT");

    sendBroadcast(intent);

    }

}

Following the changes done in the MainActivity file, then we need to create a new file MyReceiver.java which will respond to the broadcast messages.

package com.codingredefined.broadcastreceiver;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.widget.Toast;

public class MyReceiver extends BroadcastReceiver{

@Override

public void onReceive(Context context, Intent intent) {

// TODO Auto-generated method stub

Toast.makeText(context, "Broadcast Received", Toast.LENGTH_LONG).show();

}

}

Now finally we need to register our broadcast receiver in the manifest file.

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.codingredefined.broadcastreceiver"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="21" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <receiver android:name="MyReceiver">

            <intent-filter>

                <action android:name="com.codingredefined.CUSTOM_INTENT"></action>

            </intent-filter>

        </receiver>

    </application>

</manifest>

Now the application is ready to run.