Android development primer: Creating Options Menu in Android – Part III

Till now we have seen how to create and customize our Options Menu. In this post I will show you how to actually make use of the Options Menu to do something i.e. how to handle the clicks on Menu Items.

I will continue with the code from the previous post. Complete Source Code is at the bottom.

• The function we will be overriding here is, onOptionsItemSelected() from android.app.activity class.
• We will be using Toast so I would recommend you get a brief idea about what a Toast is and what it looks like from here. I will explain the different components of the Toast syntax in a while.
• Write the following code below the onCreateOptionsMenu() method or onPrepareOptionsMenu() if you have one.[java]
  public boolean onOptionsItemSelected(MenuItem item) {
  switch (item.getItemId()) {
  case 1:
  Toast.makeText(getApplicationContext(), "MenuItem1 selected", Toast.LENGTH_LONG).show();
  return true;
  case 2:
  Toast.makeText(getApplicationContext(), "MenuItem2 selected", Toast.LENGTH_LONG).show();
  return true;
  }
  return super.onContextItemSelected(item);
  }
  [/java]
• Save and execute the application in an emulator/device

Here’s a little explanation for the Toast syntax.

• getApplicationContext() : It returns the context for the whole application. It is used in order to get the context tied to the life cycle of the complete application and not some particular activity.
  
• <char_sequence_of_your_choice> : This is the text to be displayed in the Toast.
• Toast.LENGTH_LONG/Toast.LENGTH_SHORT : This defines the time for which the Toast should be visible.
• show() : Everything to the left of show() is used to create the Toast. Once created it needs to be displayed. The show() method serves this purpose

Here I have shown you how to create a Toast on the click of a menu item. You can extend this to do practically anything you want like showing dialogs, creating notifications, retrieving data from databases etc.

COMPLETE SOURCE CODE

[java]
package com.nero.myfirstapp;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class Main extends Activity {

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

@Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0, 1, 0, "MenuItem1").setIcon(R.drawable.menuitemicon1);
menu.add(0, 2, 0, "MenuItem2").setIcon(R.drawable.menuitemicon2);
return true;
}

public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case 1:
Toast.makeText(getApplicationContext(), "MenuItem1 selected", Toast.LENGTH_LONG).show();
return true;
case 2:
Toast.makeText(getApplicationContext(), "MenuItem2 selected", Toast.LENGTH_LONG).show();
return true;
}
return super.onContextItemSelected(item);
}

}

[/java]

nero