Android - Sensors:

Most of the android devices have built-in sensors that measure motion, orientation, and various environmental condition. The android platform supports three broad categories of sensors.

• Motion Sensors
• Environmental sensors
• Position sensors

Some of the sensors are hardware based and some are software based sensors. Whatever the sensor is, android allows us to get the raw data from these sensors and use it in our application. For this android provides us with some classes.
Android provides SensorManager and Sensor classes to use the sensors in our application. In order to use sensors , first thing you need to do is to instantiate the object of SensorManager class. It can be achieved as follows.

SensorManager sMgr;
sMgr = (SensorManager)this.getSystemService(SENSOR_SERVICE);

The next thing you need to do is to instantiate the object of Sensor class by calling the getDefaultSensor() method of the SensorManager class. Its syntax is given below −

Sensor light;
light = sMgr.getDefaultSensor(Sensor.TYPE_LIGHT);

Once that sensor is declared , you need to register its listener and override two methods which are onAccuracyChanged and onSensorChanged. Its syntax is as follows −

sMgr.registerListener(this, light,SensorManager.SENSOR_DELAY_NORMAL);
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
public void onSensorChanged(SensorEvent event) {
}

Getting list of sensors supported.

You can get a list of sensors supported by your device by calling the getSensorList method , which will return a list of sensors containing their name and version number and much more information. You can then iterate the list to get the information. Its syntax is given below:

sMgr = (SensorManager)this.getSystemService(SENSOR_SERVICE);
List<Sensor> list = sMgr.getSensorList(Sensor.TYPE_ALL);
for(Sensor sensor: list){
}

Apart from the these methods , there are other methods provided by the SensorManager class for managing sensors framework. These methods are listed below −

Sr.No	Method & description
1	getDefaultSensor(int type)This method get the default sensor for a given type.
2	getOrientation(float[] R, float[] values)This method returns a description of the current primary clip on the clipboard but not a copy of its data.
3	getInclination(float[] I) This method computes the geomagnetic inclination angle in radians from the inclination matrix.
4	registerListener(SensorListener listener, int sensors, int rate)This method registers a listener for the sensor
5	unregisterListener(SensorEventListener listener, Sensor sensor)This method unregisters a listener for the sensors with which it is registered.
6	getOrientation(float[] R, float[] values)This method computes the device's orientation based on the rotation matrix.
7	getAltitude(float p0, float p)This method computes the Altitude in meters from the atmospheric pressure and the pressure at sea level.

Example

Here is an example demonstrating the use of SensorManager class. It creates a basic application that allows you to view the list of sensors on your device.
To experiment with this example , you can run this on an actual device or in an emulator.

Steps	Description
1	You will use Android studio to create an Android application under a package com.example.sairamkrishna.myapplication. While creating this project, make sure you Target SDK and Compile With at the latest version of Android SDK to use higher levels of APIs.
2	Modify src/MainActivity.java file to add necessary code.
3	Modify the res/layout/activity_main to add respective XML components.
4	Run the application and choose a running android device and install the application on it and verify the results.

Following is the content of the modified MainActivity.java.

package com.example.sairamkrishna.myapplication;

import android.app.Activity;
import android.hardware.SensorManager;
import android.os.Bundle;

import android.util.Log;

import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

import android.widget.TextView;

import java.util.List;
import android.hardware.Sensor;
import android.hardware.SensorManager;

public class MainActivity extends Activity {
   TextView tv1=null;
   private SensorManager mSensorManager;
   @Override
   
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      
      tv1 = (TextView) findViewById(R.id.textView2);
      tv1.setVisibility(View.GONE);
      
      mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
      List<Sensor> mList= mSensorManager.getSensorList(Sensor.TYPE_ALL);
      
      for (int i = 1; i < mList.size(); i++) {
         tv1.setVisibility(View.VISIBLE);
         tv1.append("\n" + mList.get(i).getName() + "\n" + mList.get(i).getVendor() + "\n" + mList.get(i).getVersion());
      }
   }
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.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();
      
      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
         return true;
      }
      return super.onOptionsItemSelected(item);
   }
}

Following is the modified content of the xml activity_main.xml.

<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:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin"
   tools:context=".MainActivity"
   android:transitionGroup="true">
   
   <TextView android:text="Sensor " android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/textview"
      android:textSize="35dp"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true" />
      
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Tutorials point"
      android:id="@+id/textView"
      android:layout_below="@+id/textview"
      android:layout_centerHorizontal="true"
      android:textColor="#ff7aff24"
      android:textSize="35dp" />
      
   <ImageView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/imageView"
      android:src="@drawable/abc"
      android:layout_below="@+id/textView"
      android:layout_centerHorizontal="true"
      android:theme="@style/Base.TextAppearance.AppCompat" />
      
   <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/textView2"
        android:layout_below="@+id/imageView"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

</RelativeLayout>

Following is the content of the res/values/string.xml.

<resources>
    <string name="app_name">My Application</string>
    <string name="hello_world">Hello world!</string>
    <string name="action_settings">Settings</string>
</resources>

Following is the content of AndroidManifest.xml file.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.sairamkrishna.myapplication" >
   <application
      android:allowBackup="true"
      android:icon="@mipmap/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>
      
   </application>
</manifest>

Let's try to run our application we just modified. I assume you had created your AVD while doing environment setup. To run the app from Android studio, open one of your project's activity files and click Run icon from the toolbar. Android studio installs the app on your AVD and starts it and if everything is fine with your setup and application, it will display following Emulator window −
Now if you will look at your device screen, you will see the list of sensors supported by your device along with their name and version and other information.
If you would run this application on different devices, the output would be different because the output depends upon the number of sensors supported by your device.

 

Android - Push Notification:

 

A notification is a message you can display to the user outside of your application's normal UI. You can create your own notifications in android very easily.
Android provides NotificationManager class for this purpose. In order to use this class, you need to instantiate an object of this class by requesting the android system through getSystemService() method. Its syntax is given below −

NotificationManager NM;
NM=(NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);

After that you will create Notification through Notification class and specify its attributes such as icon,title and time e.t.c. Its syntax is given below −

Notification notify=new Notification(android.R.drawable.stat_notify_more,title,System.currentTimeMillis());

The next thing you need to do is to create a PendingIntent by passing context and intent as a parameter. By giving a PendingIntent to another application, you are granting it the right to perform the operation you have specified as if the other application was yourself.

PendingIntent pending=PendingIntent.getActivity(getApplicationContext(), 0, new Intent(),0);

The last thing you need to do is to call setLatestEventInfo method of the Notification class and pass the pending intent along with notification subject and body details. Its syntax is given below. And then finally call the notify method of the NotificationManager class.

notify.setLatestEventInfo(getApplicationContext(), subject, body,pending);
NM.notify(0, notify);  

Apart from the notify method, there are other methods available in the NotificationManager class. They are listed below −

Sr.No	Method & description
1	cancel(int id)This method cancel a previously shown notification.
2	cancel(String tag, int id)This method also cancel a previously shown notification.
3	cancelAll()This method cancel all previously shown notifications.
4	notify(int id, Notification notification)This method post a notification to be shown in the status bar.
5	notify(String tag, int id, Notification notification)This method also Post a notification to be shown in the status bar.

Example

The below example demonstrates the use of NotificationManager class. It crates a basic application that allows you to create a notification.
To experiment with this example , you need to run this on an actual device or in an emulator.

Steps	Description
1	You will use Android studio to create an Android application under a packagecom.example.sairamkrishna.myapplication. While creating this project, make sure you Target SDK and Compile With at the latest version of Android SDK to use higher levels of APIs.
2	Modify src/MainActivity.java file to add Notification code.
3	Modify layout XML file res/layout/activity_main.xml add any GUI component if required.
4	Run the application and choose a running android device and install the application on it and verify the results.

Here is the content of MainActivity.java.

package com.example.sairamkrishna.myapplication;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;

import android.graphics.Typeface;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;

import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import static java.lang.System.currentTimeMillis;

public class MainActivity extends ActionBarActivity {
   EditText ed1,ed2,ed3;
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      
      ed1=(EditText)findViewById(R.id.editText);
      ed2=(EditText)findViewById(R.id.editText2);
      ed3=(EditText)findViewById(R.id.editText3);
      Button b1=(Button)findViewById(R.id.button);
      
      b1.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            String tittle=ed1.getText().toString().trim();
            String subject=ed2.getText().toString().trim();
            String body=ed3.getText().toString().trim();
            
            NotificationManager notif=(NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
            Notification notify=new Notification(R.drawable.noti,tittle,System.currentTimeMillis());
            PendingIntent pending= PendingIntent.getActivity(getApplicationContext(), 0, new Intent(), 0);
            
            notify.setLatestEventInfo(getApplicationContext(),subject,body,pending);
            notif.notify(0, notify);
         }
      });
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.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();
      
      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
         return true;
      }
      return super.onOptionsItemSelected(item);
   }
}

Here is the content of activity_main.xml

<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:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
   
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Notification"
      android:id="@+id/textView"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:textSize="30dp" />
      .
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Tutorials Point"
      android:id="@+id/textView2"
      android:layout_below="@+id/textView"
      android:layout_centerHorizontal="true"
      android:textSize="35dp"
      android:textColor="#ff16ff01" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText"
      android:layout_below="@+id/textView2"
      android:layout_alignLeft="@+id/textView2"
      android:layout_alignStart="@+id/textView2"
      android:layout_marginTop="52dp"
      android:layout_alignRight="@+id/textView2"
      android:layout_alignEnd="@+id/textView2"
      android:hint="Name" />
   
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText2"
      android:hint="Subject"
      android:layout_below="@+id/editText"
      android:layout_alignLeft="@+id/editText"
      android:layout_alignStart="@+id/editText"
      android:layout_alignRight="@+id/editText"
      android:layout_alignEnd="@+id/editText" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:inputType="textPersonName"
      android:ems="10"
      android:id="@+id/editText3"
      android:hint="Body"
      android:layout_below="@+id/editText2"
      android:layout_alignLeft="@+id/editText2"
      android:layout_alignStart="@+id/editText2"
      android:layout_alignRight="@+id/editText2"
      android:layout_alignEnd="@+id/editText2" />
      
   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Notification"
      android:id="@+id/button"
      android:layout_marginTop="77dp"
      android:layout_below="@+id/editText3"
      android:layout_alignRight="@+id/textView"
      android:layout_alignEnd="@+id/textView" />

</RelativeLayout/7gt;

Here is the content of AndroidManifest.xml.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.sairamkrishna.myapplication" >
   
   <application
      android:allowBackup="true"
      android:icon="@mipmap/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>
      
   </application>
</manifest>

Let's try to run our application. To run the app from Android studio, open one of your project's activity files and click Run icon from the tool bar. Before starting your application, Android studio will display following window to select an option where you want to run your Android application.
Now fill in the field with the title , subject and the body. This has been shown below in the figure −
Now click on the notify button and you will see a notification in the top notification bar. It has been shown below −
Now scroll down the notification bar and see the notification. This has been shown below in the figure −

Android - Shared Preferences:

Android provides many ways of storing data of an application. One of this way is called Shared Preferences. Shared Preferences allow you to save and retrieve data in the form of key,value pair.
In order to use shared preferences , you have to call a method getSharedPreferences() that returns a SharedPreference instance pointing to the file that contains the values of preferences.

SharedPreferences sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE); 

The first parameter is the key and the second parameter is the MODE. Apart from private there are other modes available that are listed below:

Sr.No	Mode and description
1	MODE_APPENDThis will append the new preferences with the already existing preferences
2	MODE_ENABLE_WRITE_AHEAD_LOGGINGDatabase open flag. When it is set , it would enable write ahead logging by default
3	MODE_MULTI_PROCESSThis method will check for modification of preferences even if the sharedpreference instance has already been loaded
4	MODE_PRIVATEBy setting this mode , the file can only be accessed using calling application
5	MODE_WORLD_READABLEThis mode allow other application to read the preferences
6	MODE_WORLD_WRITEABLEThis mode allow other application to write the preferences

You can save something in the sharedpreferences by using SharedPreferences.Editor class. You will call the edit method of SharedPreference instance and will receive it in an editor object. Its syntax is −

Editor editor = sharedpreferences.edit();
editor.putString("key", "value");
editor.commit();

Apart from the putString method , there are methods available in the editor class that allows manipulation of data inside shared preferences. They are listed as follows:

Sr. NO	Mode and description
1	apply()It is an abstract method. It will commit your changes back from editor to the sharedPreference object you are calling
2	clear()It will remove all values from the editor
3	remove(String key)It will remove the value whose key has been passed as a parameter
4	putLong(String key, long value)It will save a long value in a preference editor
5	putInt(String key, int value)It will save a integer value in a preference editor
6	putFloat(String key, float value)It will save a float value in a preference editor

Example

This example demonstrates the use of the Shared Preferences. It display a screen with some text fields , whose value are saved when the application is closed and brought back when it is opened again .
To experiment with this example , you need to run this on an actual device on after developing the application according to the steps below:

Steps	Description
1	You will use Android studio to create an Android application under a package com.example.sairamkrishna.myapplication. While creating this project, make sure you Target SDK and Compile With at the latest version of Android SDK to use higher levels of APIs.
2	Modify src/MainActivity.java file to add progress code to display the spinning progress dialog.
3	Modify res/layout/activity_main.xml file to add respective XML code.
4	Run the application and choose a running android device and install the application on it and verify the results.

Following is the content of the modified MainActivity.java.

package com.example.sairamkrishna.myapplication;

import android.content.Context;
import android.content.SharedPreferences;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {
   EditText ed1,ed2,ed3;
   Button b1;
   public static final String MyPREFERENCES = "MyPrefs" ;
   public static final String Name = "nameKey";
   public static final String Phone = "phoneKey";
   public static final String Email = "emailKey";
   SharedPreferences sharedpreferences;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      
      ed1=(EditText)findViewById(R.id.editText);
      ed2=(EditText)findViewById(R.id.editText2);
      ed3=(EditText)findViewById(R.id.editText3);
      
      b1=(Button)findViewById(R.id.button);
      sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
      
      b1.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            String n  = ed1.getText().toString();
            String ph  = ed2.getText().toString();
            String e  = ed3.getText().toString();
            
            SharedPreferences.Editor editor = sharedpreferences.edit();
            
            editor.putString(Name, n);
            editor.putString(Phone, ph);
            editor.putString(Email, e);
            editor.commit();
            Toast.makeText(MainActivity.this,"Thanks",Toast.LENGTH_LONG).show();
         }
      });
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.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();
      
      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
         return true;
      }
      return super.onOptionsItemSelected(item);
   }
}

Following is the content of the modified main activity file res/layout/activiy_main.xml.

<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:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
   
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Shared Preference "
      android:id="@+id/textView"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:textSize="35dp" />
      
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Tutorials Point"
      android:id="@+id/textView2"
      android:layout_below="@+id/textView"
      android:layout_centerHorizontal="true"
      android:textSize="35dp"
      android:textColor="#ff16ff01" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText"
      android:layout_below="@+id/textView2"
      android:layout_marginTop="67dp"
      android:hint="Name"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText2"
      android:layout_below="@+id/editText"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      android:hint="Pass" />
      
   <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/editText3"
      android:layout_below="@+id/editText2"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      android:hint="Email" />
      
   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Save"
      android:id="@+id/button"
      android:layout_below="@+id/editText3"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="50dp" />
      
</RelativeLayout>

Following is the content of the modified content of file res/values/strings.xml.

<resources>
   <string name="app_name">My Application</string>
   <string name="hello_world">Hello world!</string>
   <string name="action_settings">Settings</string>
</resources>

Following is the content default file AndroidManifest.xml.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.sairamkrishna.myapplication" >
   
   <application
      android:allowBackup="true"
      android:icon="@mipmap/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>
      
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from Android studio, open one of your project's activity files and click Run icon from the toolbar. Before starting your application, Android studio will display following window to select an option where you want to run your Android application.
Select your mobile device as an option and then check your mobile device which will display following screen −
Now just put in some text in the field. Like i put some random name and other information and click on save button.
Now when you press save button , the text will be saved in the shared preferences. Now press back button and exit the application. Now open it again and you will see all the text you have written back in your application.

 

Android Progress Bar using ProgressDialog:

Progress bars are used to show progress of a task. For example, when you are uploading or downloading something from the internet, it is better to show the progress of download/upload to the user.
In android there is a class called ProgressDialog that allows you to create progress bar. In order to do this, you need to instantiate an object of this class. Its syntax is.

ProgressDialog progress = new ProgressDialog(this);

Now you can set some properties of this dialog. Such as, its style, its text etc.

progress.setMessage("Downloading Music :) ");
progress.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progress.setIndeterminate(true);

Apart from these methods, there are other methods that are provided by the ProgressDialog class

Sr. No	Title and description
1	getMax() This method returns the maximum value of the progress.
2	incrementProgressBy(int diff) This method increments the progress bar by the difference of value passed as a parameter.
3	setIndeterminate(boolean indeterminate) This method sets the progress indicator as determinate or indeterminate.
4	setMax(int max) This method sets the maximum value of the progress dialog.
5	setProgress(int value) This method is used to update the progress dialog with some specific value.
6	show(Context context, CharSequence title, CharSequence message) This is a static method, used to display progress dialog.

Example

This example demonstrates the horizontal use of the progress dialog which is in fact a progress bar. It display a progress bar on pressing the button.
To experiment with this example, you need to run this on an actual device after developing the application according to the steps below.

Steps	Description
1	You will use Android studio to create an Android application under a package com.example.sairamkrishna.myapplication. While creating this project, make sure you Target SDK and Compile With at the latest version of Android SDK to use higher levels of APIs.
2	Modify src/MainActivity.java file to add progress code to display the progress dialog.
3	Modify res/layout/activity_main.xml file to add respective XML code.
4	Run the application and choose a running android device and install the application on it and verify the results.

Following is the content of the modified main activity file src/MainActivity.java.

package com.example.sairamkrishna.myapplication;

import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {
   Button b1;
   private ProgressDialog progress;
   
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      b1 = (Button) findViewById(R.id.button2);
   }
   
   public void download(View view){
      progress=new ProgressDialog(this);
      progress.setMessage("Downloading Music");
      progress.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
      progress.setIndeterminate(true);
      progress.setProgress(0);
      progress.show();
      
      final int totalProgressTime = 100;
      final Thread t = new Thread() {
         @Override
         public void run() {
            int jumpTime = 0;
            
            while(jumpTime < totalProgressTime) {
               try {
                  sleep(200);
                  jumpTime += 5;
                  progress.setProgress(jumpTime);
               }
               catch (InterruptedException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
               }
            }
         }
      };
      t.start();
   }
}

Modify the content of res/layout/activity_main.xml to the following −

<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:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
   
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/textView"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:textSize="30dp"
      android:text="Progress bar" />
      
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Tutorials Point"
      android:id="@+id/textView2"
      android:layout_below="@+id/textView"
      android:layout_centerHorizontal="true"
      android:textSize="35dp"
      android:textColor="#ff16ff01" />
      
   <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Download"
      android:onClick="download"
      android:id="@+id/button2"
      android:layout_marginLeft="125dp"
      android:layout_marginStart="125dp"
      android:layout_centerVertical="true" />
      
</RelativeLayout>

This is the default AndroidManifest.xml−

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.sairamkrishna.myapplication" >
   <application
      android:allowBackup="true"
      android:icon="@mipmap/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>
   
    </application>
</manifest>

Let's try to run your application. We assume, you have connected your actual Android Mobile device with your computer. To run the app from Android studio, open one of your project's activity files and click Run icon from the toolbar. Before starting your application, Android studio will display following window to select an option where you want to run your Android application.
Select your mobile device as an option and then check your mobile device which will display following screen −
Just press the button to start the Progress bar. After pressing, following screen would appear −
It will continuously update itself.