How to show notification with navigation to another Activity in android?

NotificationCompat.Builder b=new NotificationCompat.Builder(this);


b.setSmallIcon(R.drawable.ic_launcher);
b.setContentTitle("My Notification");
b.setContentText("click here to navigate Activity2");
Date d=new Date();
long i=(long)d.getTime();
Intent notificationIntent=new Intent(this,Activity2.class);
PendingIntent pintent=PendingIntent.getActivity(this,0,notificationIntent,PendingIntent.FLAG_UPDATE_CURRENT);
b.setContentIntent(pintent);

NotificationManager nManager=(NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
nManager.notify((int)i,b.build());

AutoComepleteTextView example in android?

AutoCompleteTextView:

          Android AutoCompleteTextView is an editable text field, it displays a list of suggestions in a drop down menu automatically while the user is entering the characters from which user can select only one suggestion.
              To use AutoCompleteTextView you have to first create an AutoCompleteTextView field in the xml file. its syntax is given below.

<AutoCompleteTextView
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:id="@+id/actv"
        android:completionThreshold="1"/>

After this now get the reference of AutoComepleteTextView as below.

AutoCompleteTextView actv=(AutoCompleteTextView)findViewById(R.id.actv);

The next thing you need to do is to specify the list of suggestions items to be displayed. You can specify the list items as an ArrayList in java. Syntax is given below.

final ArrayList<String> list=new ArrayList<String>();
  list.clear();
  list.add("India");
  list.add("Pakistan");
  list.add("china");
  list.add("US");

ArrayAdapter<String> adp=new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_list_item_1,list);
actv.setAdapter(adp);

The array adapter class is responsible for displaying the data as list in the suggestion box of the text field. The setAdapter method is used to set the adapter of the autoCompleteTextView. Apart from these methods, the other methods of Auto Complete are listed below.        

Sr.No	Method & description
1	getAdapter() This method returns a filterable list adapter used for auto completion
2	getCompletionHint() This method returns optional hint text displayed at the bottom of the the matching list
3	getDropDownAnchor() This method returns returns the id for the view that the auto-complete drop down list is anchored to.
4	getListSelection() This method returns the position of the dropdown view selection, if there is one
5	isPopupShowing() This method indicates whether the popup menu is showing
6	setText(CharSequence text, boolean filter) This method sets text except that it can disable filtering
7	showDropDown() This method displays the drop down on screen.

Android AutoCompleteTextView Example:

Step1)  In order to use AutoCompleteTextView you have to first create an AutoCompletTextView Field in the xml. Its syntax is given below. Create activity.xml file in layout folder and write the below code.

activity.xml

<?xml version="1.0" encoding="utf-8"?>
<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="home.actvtest.MainActivity">  

    <AutoCompleteTextView    

         android:layout_width="match_parent" 

         android:layout_height="70dp"    

         android:id="@+id/actv"     

         android:completionThreshold="1"/>

</RelativeLayout>

Step 2) Create MainActivity.java in java folder and write the below code.

MainActivity.java

package home.actvtest;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import java.util.ArrayList;

public class MainActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        AutoCompleteTextView actv=(AutoCompleteTextView)findViewById(R.id.actv);

        final ArrayList<String> list=new ArrayList<String>();
        list.clear();

        list.add("India");
        list.add("Pakistan");
        list.add("china");
        list.add("US");
        list.add("Banglaedesh");
        list.add("Barma");
        list.add("Rashya");
        list.add("Iran");
        list.add("Iraq");
        list.add("Itali");
        list.add("Brezil");
        list.add("Srilanka");

        ArrayAdapter<String> adp=new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_list_item_1,list);

        actv.setAdapter(adp);

    }
}

Step3) write the below code in AndroidManifest.xml

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

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="home.actvtest">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>

Output:

Java Interview questions and Answers?

Q: What is the difference between Abstract class and interface?

Ans:

Abstract Class	Interface
1) Abstract class can have abstract and non- abstract methods.	1) Interface can have only abstract methods.
2) It doesn't support Multiple Inheritance.	2) Interface Supports Multiple Inheritance
3) Abstract keyword is used to declare Abstract class	3) interface keyword is used to declare an interface.
4) Abstract class can contain static,non-static, final, non-final variables.	4) by default Interface variables are only static & final.
5) Abstract class can have static methods, main method.	5) Interface can't contain static method , main method.
6) Abstract class can contains Constructors	6) Interface can't contain Constructors.
7) Abstract class methods can be declared with public and non-public	7) By default all interface methods are public & abstract.
8) A abstract class can provide implement of interface.	8) A interface can't provide implementation of abstract class.
9) A abstract class can extends only one class.	9) A interface can extends any number of interfaces.
10) Object class is super class to all classes.	10) There is no super class for interface.
Ex: public abstract class B {       public abtract void fun1();       void fun2(); } public class A extends B {     public void fun1()     {            System.out.println("fun1 of class A is    calling");     }     public void fun2()    {         System.out.println("fun2 of class A is calling");     }    public static void main(String[] a)    {           A a1=new A();           a1.fun1();           a1.fun2();    } } O/P: fun1 of class A is calling fun2 of class A is calling	Ex: interface B {      int x=10;      void fun1(); } public class A  implements  B {      public void fun1()      {          System.out.println("fun1 of class A is calling");      }    public static void main(String[] a)   {          A a1=new A();          a1.fun1();    } } O/P: fun1 of class A is calling

RecyclerView with CardView in android example?

RecyclerView:

    RecyclerView is more advanced and flexible alternative for ListView. In ListView custom adapter every time it will create new object for UI binding. where as coming to RecyclerView it won't create multiple times. View will created only once.

   In order to implement RecyclerView, first of all we need to decide the Layout Manager for RecyclerView.

LayoutManager type:
1) LinearLayoutManager               :  It shows the items in vertical or horizontal scrolling list.
2) GridLayoutManager                  :  Shows items in a grid.
3) StaggeredGridLayoutManager  :  Shows items in a staggered grid.


CardView
       CardView is used to show the information inside a card which is consistent. By using this we can apply shadow effect, rounded corner etc. To show shadow effect there is a property called card_view:cardElevetion attribute. in order to show rounded corners card_view:cardCornerRadius property.

Example Sample project to display names & initials names of friends.

Step 1: For Accessing RecyclerView & CardView, First we need to import few libraries in build.gradle file of app.

compile 'com.android.support:appcompat-v7:23.0+'
compile 'com.android.support:recyclerview-v7:23.0+'
compile 'com.android.support:cardview-v7:23.0+'

So build.gradle file of app level looks like this.

apply plugin: 'com.android.application'
android {
    compileSdkVersion 23    buildToolsVersion "24.0.1"
    defaultConfig {
        applicationId "com.example.srikanthp.rctest"       

        minSdkVersion 15        

        targetSdkVersion 23        

        versionCode 1        

        versionName "1.0"    

    }
    buildTypes {
        release 

         {
            minifyEnabled false            

            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

        }
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'    

    compile 'com.android.support:appcompat-v7:23.0+'   

    compile 'com.android.support:recyclerview-v7:23.0+'    

    compile 'com.android.support:cardview-v7:23.0+'

}

Steps 2: Create a xml file in layout folder with the name of activity_main.xml and paste the below code.

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

<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.example.srikanthp.rctest.MainActivity">

        <android.support.v7.widget.RecyclerView        

             android:layout_width="match_parent"       

             android:layout_height="match_parent"     

             android:id="@+id/recyclerView"       

             android:scrollbars="vertical">

      </android.support.v7.widget.RecyclerView>

</RelativeLayout>

Step 3: Now create a class with the name of MainActivity.java and paste the below code.

package com.example.srikanthp.rctest;
import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

import java.util.ArrayList;

public class MainActivity extends Activity
{
    ArrayList<String> first_names,initials_names;
    RecyclerView recyclerView;
    RecyclerView.Adapter adapter;
    RecyclerView.LayoutManager lManager;

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        getData();

        recyclerView=(RecyclerView)findViewById(R.id.recyclerView);
        lManager=new LinearLayoutManager(this);

        recyclerView.setLayoutManager(lManager);
        adapter=new MyAdapter(first_names,initials_names);

        recyclerView.setAdapter(adapter);
    }



    public void getData()
    {
        first_names=new ArrayList<String>();
        first_names.clear();
        first_names.add("SrikanthP");
        first_names.add("Mahesh");
        first_names.add("Naveen");
        first_names.add("Srinivas");
        first_names.add("Pawan");
        first_names.add("SrikanthK");
        first_names.add("Ramakanth");
        first_names.add("Sathish");
        first_names.add("Sridhar");
        first_names.add("Vishwanath");

        initials_names=new ArrayList<String>();
        initials_names.clear();
        initials_names.add("Patel");
        initials_names.add("Thippal");
        initials_names.add("Veerabattini");
        initials_names.add("Vanka");
        initials_names.add("Motkuri");
        initials_names.add("Kadari");
        initials_names.add("Kota");
        initials_names.add("Gangishetty");
        initials_names.add("Metraskar");
        initials_names.add("Kota");
    }

}

Note : for creating adapter class we need to create mydapter.xml(in layout folder) & MyAdapter.java(in java folder) .

Step 4: Now create myadaper.xml file in layout folder and paste the below code.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"   
    android:orientation="horizontal"
    android:layout_width="match_parent"  
    android:layout_height="match_parent"   
    android:layout_margin="10dp"   
    xmlns:app="http://schemas.android.com/apk/res-auto">

        <android.support.v7.widget.CardView            
          android:layout_width="match_parent"          
          android:layout_height="match_parent"          
          app:cardCornerRadius="10dp"   
          android:elevation="10dp">

           <LinearLayout      
               android:layout_width="match_parent"   
               android:layout_height="match_parent"
               android:orientation="horizontal">

                  <TextView 
                    android:id="@+id/tvNames"
                    android:layout_width="0dp"
                    android:layout_weight="0.6"
                    android:layout_height="wrap_content"
                    android:text="Names.."
                    android:textSize="30sp"
                    android:textStyle="bold"/>

                <TextView 
                    android:id="@+id/tvInitials"
                    android:layout_width="0dp"
                    android:layout_weight="0.6"
                    android:layout_height="wrap_content"
                    android:text="Initial names.."
                    android:textSize="30sp"
                    android:textStyle="bold"/>

            </LinearLayout>

        </android.support.v7.widget.CardView>

</LinearLayout>

Step 5: Create a class with the name of MyAdapter.java and paste below code.

package com.example.srikanthp.rctest;

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.lang.reflect.Array;
import java.util.ArrayList;

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>
{

    ArrayList<String> names,initials;


    public MyAdapter(ArrayList<String> nm,ArrayList<String> nt)
    {
        this.names=nm;
        this.initials=nt;
    }

    public static class ViewHolder extends  RecyclerView.ViewHolder
    {
        TextView tvNames,tvInitials;

        public ViewHolder(View v)
        {
            super(v);
            tvNames=(TextView)v.findViewById(R.id.tvNames);
            tvInitials=(TextView)v.findViewById(R.id.tvInitials);
        }
    }

    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View v= LayoutInflater.from(parent.getContext()).inflate(R.layout.myadapter,parent,false);

        ViewHolder hold=new ViewHolder(v);

        return hold;
    }

    @Override    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.tvNames.setText(names.get(position));
        holder.tvInitials.setText(initials.get(position));
    }

    @Override    public int getItemCount() {
        return names.size();
    }

}

Android interview questions and answers

1) Difference between main thread(UI thread) and worker thread?

People use the word "worker" when they mean a thread that does not own or interact with UI.  Threads that do handle UI are called "UI" threads. Usually, your main (primary) thread will be the thread that owns and manages UI. And then you start one or more worker threads that do specific tasks.

2) Difference between Service and Intent Service?

Service	IntentService
1)      The Service runs in background but it runs on the Main Thread of the application.	1)      The IntentService runs on a separate worker thread.
2)      The Service can be used in tasks with no UI, but shouldn't be too long. If you need to perform long tasks, you must use threads within Service.	2)  The IntentService can be used in long tasks usually with no communication to Main Thread. If communication is required, can use Main Thread handler or broadcast intents. Another case of use is when callbacks are needed (Intent triggered tasks)
3)      The Service is triggered by calling method startService().	3)  The IntentService is triggered using an Intent, it spawns a new worker thread and the method onHandleIntent() is called on this thread.
4)      The Service may be triggered from any thread, activity or other application component.	4) IntentService may be triggered from any thread, activity or other application component.
5)      The Service may block the Main Thread of the application	5) The IntentService cannot run tasks in parallel. Hence all the consecutive intents will go into the message queue for the worker thread and will execute sequentially.
6)       It is our responsibility to stop the service when its work is done, by calling stopSelf() or stopService().	6) The IntentService stops the service after all start requests have been handled, so you never have to call stopSelf().

3) Difference between Intent , sticky intent and pending intent?

Intent - is a message passing mechanism b/w components of android except for contentProviders
Sticky Intent - Sticks with android, for future broadcast listeners. sticky intent is a broadcast from sendStickyBroadCast() method, such that it floats arround even afyer broadcast, allowing others to collect data from it.
Pending intent - will be used when some one wants to fire an intent in future and may be at that ttime app is not alive.