Android Intent and its types

Posted By : Sapna Sharma | 30-Jun-2015

android

Intent

Intent is the message that is passed between components such as activities, content providers, broadcast receivers, services etc.

The dictionary meaning of intent is intention or purpose. So, it can be described as the intention to do action.

Intent is used to perform various action like:

1. Start the service

2. Launch an activity

3. Display a web page

4. Display a list of contacts

5. Broadcast a message

6. Dial a phone call etc.

Intent Types

In android, intent is of two types : implicit and explicit

Implicit Intent

Implicit Intent doesn't specifiy the component. In such case, intent provides information of available components provided by the system that is to be invoked.

Implicit intent example to diaplay a web page

UI for this example containts only a button on click of which you will redirect to web page.

activity_main.xml

MainActivity.java

package com.exp.implicitintent;  
      
    import android.net.Uri;  
    import android.os.Bundle;  
    import android.app.Activity;  
    import android.content.Intent;  
    import android.view.View;  
    import android.view.View.OnClickListener;  
    import android.widget.Button;   
      
    public class MainActivity extends Activity {  
        @Override  
        protected void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  
            setContentView(R.layout.activity_main);   
 
            Button button1=(Button)findViewById(R.id.button1);  
              
            button1.setOnClickListener(new OnClickListener() {  
                  
                @Override  
                public void onClick(View arg0) {  
                    String url="www.oodlestechnologies.com";  
                    Intent intent=new Intent(Intent.ACTION_VIEW,Uri.parse(url));  
                    startActivity(intent);  
                }  
            });  
        }

Explicit Intent

Explicit intent specifies the component that is which class to be invoked. We can pass the information from one activity to another using explicit intent.

Explicit intent exapmle to call one activity from another activity and passing data

UI for this example contains two activities both containing a button and a text view.

activityone_main.xml

activitytwo_main.xml

MainActivityOne.java

package com.example.explicitintent;  
      
    import android.os.Bundle;  
    import android.app.Activity;  
    import android.content.Intent;  
    import android.view.Menu;  
    import android.view.View;  
    import android.view.View.OnClickListener;  
    import android.widget.Button;  
    import android.widget.Toast;  
      
    public class ActivityOne extends Activity {  
      
          @Override  
          public void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  
            setContentView(R.layout.activity_main);  
              
            Button button1=(Button)findViewById(R.id.Button01);  
              
            button1.setOnClickListener(new OnClickListener(){  
             public void onClick(View view) {  
              Intent i = new Intent(getApplicationContext(), MainActivityTwo.class);  
              i.putExtra("Value", "Welcome to second activity");  
              startActivity(i);  
             }  
             });  
          }        
        }

MainActivityTwo.java

package com.example.explicitintent;  
      
    import android.app.Activity;  
    import android.content.Intent;  
    import android.os.Bundle;  
    import android.view.View;  
    import android.view.View.OnClickListener;  
    import android.widget.Button;  
    import android.widget.EditText;  
    import android.widget.TextView;  
    import android.widget.Toast;  
      
    public class ActivityTwo extends Activity {  
      
      @Override  
      public void onCreate(Bundle bundle) {  
        super.onCreate(bundle);  
          
        TextView tv=new TextView(this);  
        tv.setText("second activity");  
        setContentView(R.layout.activity_two);  
          
        Bundle extras = getIntent().getExtras();  
        String value = extras.getString("Value");  
          
        Toast.makeText(getApplicationContext(),"Value is: "+value1,Toast.LENGTH_LONG).show();  
          
        Button button1=(Button)findViewById(R.id.Button01);  
          
        button1.setOnClickListener(new OnClickListener(){  
            public void onClick(View view) {  
                Intent i = new Intent(getApplicationContext(), MainActivityOne.class);  
                startActivity(i);  
              }  
        });  
      }  
    }

Thanks