How to start Android Activity and pass Variables from One Activity to Another.

Its pretty  much easy to start a activity and pass variables from one activity to another.This post will show you step by step how to...

Its pretty  much easy to start a activity and pass variables from one activity to another.This post will show you step by step how to do this.

1.Our first step is to write MainActivity where am going to add two EditText i.e username and password fields  and a Button then will send action.Then am going to pass these two variables to my next activity using Intent and Display them.

MainActivity  Layout  XML Code.

MainActivity Java Code

package net.techoverload.myfirstapp;

import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;

import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.appindexing.Thing;
import com.google.android.gms.common.api.GoogleApiClient;


public class MainActivity extends AppCompatActivity {

    public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
    public final static  String EXTRA_PASSWORD="com.example.myfirstapp.PASSWORD";
    /**
     * ATTENTION: This was auto-generated to implement the App Indexing API.
     * See https://g.co/AppIndexing/AndroidStudio for more information.
     */
    private GoogleApiClient client;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       Toolbar myToolBar= (Toolbar)findViewById(R.id.my_toolbar) ;
        setSupportActionBar(myToolBar);


        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
    }
@Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        switch (item.getItemId())
        {
            case R.id.action_favorite:
                return true;
            case R.id.action_settings:
                return true;
            default:
                return super.onOptionsItemSelected(item);


        }



    }
    /*Implementing  sendMessage method*/
    public void sendMessage(View view) {
        EditText message = (EditText) findViewById(R.id.username);
        EditText password = (EditText) findViewById(R.id.password);
        String pass = password.getText().toString();
        String text = message.getText().toString();
        Intent intent = new Intent(this,DisplayActivity.class);
        intent.putExtra(EXTRA_PASSWORD,pass);
        intent.putExtra(EXTRA_MESSAGE, text);

        startActivity(intent);
    }

    /**
     * ATTENTION: This was auto-generated to implement the App Indexing API.
     * See https://g.co/AppIndexing/AndroidStudio for more information.
     */
    public Action getIndexApiAction() {
        Thing object = new Thing.Builder()
                .setName("Main Page") // TODO: Define a title for the content shown.
                // TODO: Make sure this auto-generated URL is correct.
                .setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
                .build();
        return new Action.Builder(Action.TYPE_VIEW)
                .setObject(object)
                .setActionStatus(Action.STATUS_TYPE_COMPLETED)
                .build();
    }

    @Override
    public void onStart() {
        super.onStart();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client.connect();
        AppIndex.AppIndexApi.start(client, getIndexApiAction());
    }

    @Override
    public void onStop() {
        super.onStop();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        AppIndex.AppIndexApi.end(client, getIndexApiAction());
        client.disconnect();
    }
}

Second Activity Layout XML File

Second Activity Java Code

package net.techoverload.myfirstapp;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.TextView;

import org.w3c.dom.Text;

public class DisplayActivity extends AppCompatActivity {

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


        Intent intent=getIntent();
        String message=intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
        String pass=intent.getStringExtra(MainActivity.EXTRA_PASSWORD);


       EditText editUsername=(EditText)findViewById(R.id.edit_username);
        EditText editPass =(EditText)findViewById(R.id.edit_password);
                editUsername.setText(message);
        editPass.setText(pass);






    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        switch (item.getItemId())
        {
            case R.id.action_favorite:
                return true;
            case R.id.action_settings:
                return true;
            default:
                return super.onOptionsItemSelected(item);


        }



    }

}

Code to pass Variables to the other activity

 /*Implementing  sendMessage method*/
    public void sendMessage(View view) {
        EditText message = (EditText) findViewById(R.id.username);
        EditText password = (EditText) findViewById(R.id.password);
        String pass = password.getText().toString();
        String text = message.getText().toString();
        Intent intent = new Intent(this,DisplayActivity.class);
        intent.putExtra(EXTRA_PASSWORD,pass);
        intent.putExtra(EXTRA_MESSAGE, text);

        startActivity(intent);
    }

    /**

Retrieving Variables from the other activity  

Intent intent=getIntent();
        String message=intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
        String pass=intent.getStringExtra(MainActivity.EXTRA_PASSWORD);


       EditText editUsername=(EditText)findViewById(R.id.edit_username);
        EditText editPass =(EditText)findViewById(R.id.edit_password);
                editUsername.setText(message);
        editPass.setText(pass);