Dialog in Android

It is a small window that appears before the activity and then the activity loses attention and the Dialog gains all user focus. They are of different types:

1)Alert Dialog

2)Progress Dialog

3)Date picker

4)Time Picker

In this article I would like to discuss about Alert Dialog.

Dialog is the base class for creating dialogs. We usually use its subclasses for creating dialog depending on the type of dialogs we use in our applications.

The subclass we use for creating alert dialog is AlertDialog.

First of all we need to create a Builder object of the class AlertDialog.Builder.

Here it is,

AlertDialog.Builder builder1=new AlertDialog.Builder(MyAlertdialogActivity.this);

where MyAlertDialogActivity is my activity here.

Next is setting the message for your dialog.

Here,
builder1.setMessage("Please Press Ok");

Now, I’ll jot down the code for alert dialog with one button. We use the method setNeutralButton() for that as shown below.

builder1.setNeutralButton("OK",new DialogInterface.OnClickListener() {
  @Override
  public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
  Toast.makeText(getApplicationContext(), "Ok is pressed", Toast.LENGTH_LONG).show();
  }
  });

Here, DialogInterface in the code is used to allow some code to be run when an item on the dialog is clicked. Here I’ve given a Toast which says ‘Ok is pressed’ when the neutral button ‘OK’ is clicked.

Hope this made everything in the code so far clear.

Finally, we need to create the Alert Dialog with the features defined(ie,the message,the button ,Toast message etc) and display the same. So, the code for that is

builder1.show();

The code written together looks like this:

btnalert1.setOnClickListener(new OnClickListener() {  @Override  public void onClick(View v) {
// TODO Auto-generated method stub  AlertDialog.Builder builder1=new AlertDialog.Builder(MyAlertdialogActivity.this);
builder1.setMessage("Please Press Ok");  builder1.setNeutralButton("OK",new DialogInterface.OnClickListener() {  @Override  public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub  Toast.makeText(getApplicationContext(), "Ok is pressed", Toast.LENGTH_LONG).show();
 }  });  builder1.show();  }  });

where btnalert1 is the Button which on clicking displays the alert dialog.

And the output looks like this:

When Ok is clicked the screen looks like this:

We can also create Alert Dialog with Buttons side-by-side. Here is the code,

  AlertDialog.Builder builder2=new AlertDialog.Builder(MyAlertdialogActivity.this);
  builder2.setMessage("Press OK or Cancel");
  builder2.setPositiveButton("OK",new DialogInterface.OnClickListener() {

  @Override
public void onClick(DialogInterface dialog, int which) {

// TODO Auto-generated method stub

  Toast.makeText(getApplicationContext(), "U Clicked OK", Toast.LENGTH_LONG).show();

  }

  });

  builder2.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

@Override
  
public void onClick(DialogInterface dialog, int which) {

// TODO Auto-generated method stub

  Toast.makeText(getApplicationContext(), "U Clicked Cancel ", Toast.LENGTH_LONG).show();

  }

  });

  builder2.show();

This is how the output looks:

When the OK button is clicked:

Now just check how we can create an Alert Dialog with a list of choices. The code for the same is

final CharSequence[] items={"One","two","three"};

  btnalertlist.setOnClickListener(new OnClickListener() {

  @Override

  public void onClick(View v) {

// TODO Auto-generated method stub
  
AlertDialog.Builder builder3=new AlertDialog.Builder(MyAlertdialogActivity.this);
  builder3.setTitle("Pick your choice").setItems(items, new DialogInterface.OnClickListener() {

  @Override

  public void onClick(DialogInterface dialog, int which) {

// TODO Auto-generated method stub
  
Toast.makeText(getApplicationContext(), "U clicked "+items[which], Toast.LENGTH_LONG).show();
  
}
  
});

  builder3.show();

  }

  });

This is how the output for this looks:

When one is chosen, the screen looks like this:

The whole code is given below:

package com.deepthi.alertdialog;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MyAlertdialogActivity extends Activity {
/** Called when the activity is first created. */
Button btnalert1,btnalert2,btnalertlist;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnalert1=(Button)findViewById(R.id.btndialog1);
btnalert1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
AlertDialog.Builder builder1=new AlertDialog.Builder(MyAlertdialogActivity.this);
builder1.setMessage("Please Press Ok");
builder1.setNeutralButton("OK",new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "Ok is pressed", Toast.LENGTH_LONG).show();
}
});
builder1.show();
}
});
btnalert2=(Button)findViewById(R.id.btndialog2);
btnalert2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
AlertDialog.Builder builder2=new AlertDialog.Builder(MyAlertdialogActivity.this);
builder2.setMessage("Press OK or Cancel");
builder2.setPositiveButton("OK",new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "U Clicked OK", Toast.LENGTH_LONG).show();
}
});
builder2.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "U Clicked Cancel ", Toast.LENGTH_LONG).show();
}
});
builder2.show();
}
});
btnalertlist=(Button)findViewById(R.id.btndialog3);
final CharSequence[] items={"One","two","three"};
btnalertlist.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
AlertDialog.Builder builder3=new AlertDialog.Builder(MyAlertdialogActivity.this);
builder3.setTitle("Pick your choice").setItems(items, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "U clicked "+items[which], Toast.LENGTH_LONG).show();
}
});
builder3.show();
}
});
}
}

I’m planning to post articles regarding Progress Dialog, Date Picker and Time Picker also.So keep reading and also share your experiences working with android.