Android Intents Tutorial

// Create the Intent with the target of Greeting Activity.
// Intent(FirstActivity, SecondActivity.class)
Intent intent = new Intent(this,GreetingActivity.class);

// The data attached
intent.putExtra("firstName",firstName);
intent.putExtra("lastName", lastName);

// Start Activity (GreetingActivity)
// (No need feedback from the activity is called)
this.startActivity(intent);


// Start Activity and will have a feedback from the activity is called.
this.startActivityForResult(intent, MY_REQUEST_CODE);

// Way 1.
Intent mIntent = new Intent(this, GreetingActivity.class);
Bundle extras = mIntent.getExtras();
extras.putString("firstName", "<firstName>");
extras.putString("látName", "<lastName>");

// Way 2.
Intent mIntent2 = new Intent(this, GreetingActivity.class);
Bundle mBundle = new Bundle();
mBundle.putString("firstName", "<firstName>");
mBundle.putString("látName", "<lastName>");
mIntent2.putExtras(mBundle);

// Way 3:
// Using putExtra()
Intent mIntent3 = new Intent(this, GreetingActivity.class);
mIntent3.putExtra("firstName", "<firstName>");
mIntent3.putExtra("látName", "<lastName>");

Intent intent = this.getIntent();

String firstName= intent.getStringExtra("firstName");
String lastName = intent.getStringExtra("lastName");

// Or
Bundle extras = this.getIntent().getExtras();

String firstName1 = extras.getString("firstName");
String lastName2  = extras.getString("lastName");

package org.o7planning.explicitintentexample;

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

public class MainActivity extends AppCompatActivity {

   private EditText textFirstName;
   private EditText textLastName;
   private TextView textFeedback;

   public static final int MY_REQUEST_CODE = 100;

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

       this.textFirstName = (EditText)this.findViewById(R.id.text_firstName);
       this.textLastName = (EditText)this.findViewById(R.id.text_lastName);
       this.textFeedback = (TextView)this.findViewById(R.id.text_feedback);
   }

   // When 'Greeting Activity' completed, it sends back a feedback.
   // (If you have started it by startActivityForResult())
   @Override
   protected void onActivityResult(int requestCode, int resultCode, Intent data) {
       if (resultCode == Activity.RESULT_OK && requestCode == MY_REQUEST_CODE ) {
           String feedback = data.getStringExtra("feedback");
           this.textFeedback.setText(feedback);
       } else {
           this.textFeedback.setText("!?");
       }
   }

   // The method is called when the user clicks on "Show Greeting" button.
   public void showGreeting(View view)  {
        String firstName= this.textFirstName.getText().toString();
        String lastName= this.textLastName.getText().toString();

       Intent intent = new Intent(this,GreetingActivity.class);
       intent.putExtra("firstName", firstName);
       intent.putExtra("lastName", lastName);

       // Start Activity and no need feedback.
       // this.startActivity(intent);

       // Start Activity and get feedback.
       this.startActivityForResult(intent, MY_REQUEST_CODE);
   }

}

package org.o7planning.explicitintentexample;

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

public class GreetingActivity extends AppCompatActivity {

   private String firstName;
   private String lastName;

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

       // Intent is passed into
       Intent intent = this.getIntent();

       this.firstName= intent.getStringExtra("firstName");
       this.lastName = intent.getStringExtra("lastName");

       String greeting = "Hello "+ firstName+" "+ lastName;

       TextView textGreeting =(TextView) this.findViewById(R.id.text_greeting);

       textGreeting.setText(greeting);
   }

   // When completed this Activity, send feedback to the caller.
   @Override
   public void finish() {
       // Prepare data intent
       Intent data = new Intent();
       data.putExtra("feedback", "I'm "+ this.firstName+", Hi!");
       // Activity finished ok, return the data
       this.setResult(Activity.RESULT_OK, data);
       super.finish();
   }


   // The method is called when the user clicks the Back button.
   public void backClicked(View view)  {
       // Calling onBackPressed().
       // Gọi phương thức onBackPressed().
       this.onBackPressed();
   }

 
}

// An implicit intent, requested to view a URL

Intent intent = new Intent (Intent.ACTION_VIEW, Uri.parse("//o7planning.org"));
startActivity(intent);

package org.o7planning.implicitintentexample;

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

public class MainActivity extends AppCompatActivity {


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

   // The method is called when the user clicks on "Go Google" button.
   public void goGoogle(View view)  {
       String url="http://google.com";

       // An implicit intent, request a URL.
       Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
       this.startActivity(intent);
   }

   // The method is called when the user clicks on "Send Email" button.
   public void sendEmail(View view)  {

       // List of recipients
       String[] recipients=new String[]{"[email protected]"};

   
       String subject="Hi, how are you!";

     
       String content ="This is my test email";

       Intent intentEmail = new Intent(Intent.ACTION_SEND, Uri.parse("mailto:"));
       intentEmail.putExtra(Intent.EXTRA_EMAIL, recipients);
       intentEmail.putExtra(Intent.EXTRA_SUBJECT, subject);
       intentEmail.putExtra(Intent.EXTRA_TEXT, content);

       intentEmail.setType("text/plain");

       startActivity(Intent.createChooser(intentEmail, "Choose an email client from..."));
   }



}