Android Tutorials


ActionBars.


1. How to start with ActionBar in Android?

With Android 3.0 Google eliminated the need of hardware menu button which is replaced by Action Bars.

Here is a quick example on how to use ActionBars.

First create a new project and name it ActionBarExample.

Now create a folder named “menu” in res folder and create a new XML file inside it named “action_bar_menu.xml”.

action_bar_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:id="@+id/menuitem1" android:showAsAction="ifRoom" android:title="Test1"></item>
    <item android:id="@+id/menuitem2" android:showAsAction="ifRoom" android:title="Test2"></item>
</menu>

Now the java code for implementing this ActionBar.

MainActivity.java

package com.example.actionbarexample;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends Activity {
	@Override
	  public void onCreate(Bundle savedInstanceState) {   
	    super.onCreate(savedInstanceState);
	    setContentView(R.layout.activity_main);
	  }

	  @Override
	  public boolean onCreateOptionsMenu(Menu menu) {
	    MenuInflater inflater = getMenuInflater();
	    inflater.inflate(R.menu.action_bar_menu, menu);
	    return true;
	  }

	  @Override
	  public boolean    onOptionsItemSelected(MenuItem item) {
	    switch (item.getItemId()) {
	    case R.id.menuitem1:
	      Toast.makeText(this, "Test 1 Clicked", Toast.LENGTH_SHORT).show();
	      break;
	    case R.id.menuitem2:
	      Toast.makeText(this, "Test 2 Clicked", Toast.LENGTH_SHORT).show();
	      break;

	    default:
	      break;
	    }

	    return true;
	  }
	} 

As there is enough space in the ActionBar otherwise you may see the Overflow menu or you have to use the Option menu button on your phone.

Action Bar in Android

==========================================================================================================================================


2. Dynamically Adding, Removing, Toggling and Removing all ActionBar Tabs in Android – Part 2?

This simple java code does that.

First create a project and in the MainActivity, paste this.

package com.coderzheaven.actionbartabs;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.action_bar_tabs); 
    }

    public void onAddTab(View v) {
        final ActionBar bar = getActionBar();
        final int tabCount = bar.getTabCount();
        final String text = "Tab " + tabCount;
        bar.addTab(bar.newTab()
                .setText(text)
                .setTabListener(new TabListener(new TabContentFragment(text))));
    }

    public void onRemoveTab(View v) {
        final ActionBar bar = getActionBar();
        if(bar.getTabCount() > 0)
        	bar.removeTabAt(bar.getTabCount() - 1);
    }

    public void onToggleTabs(View v) {
        final ActionBar bar = getActionBar();

        if (bar.getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS) {
            bar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
            bar.setDisplayOptions(ActionBar.DISPLAY_SHOW_TITLE, ActionBar.DISPLAY_SHOW_TITLE);
        } else {
            bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
            bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);
        }
    }

    public void onRemoveAllTabs(View v) {
        getActionBar().removeAllTabs();
    }

    /**
     * A TabListener receives event callbacks from the action bar as tabs
     * are deselected, selected, and reselected. 
     **/
    private class TabListener implements ActionBar.TabListener {
        private TabContentFragment mFragment;

        public TabListener(TabContentFragment fragment) {
            mFragment = fragment;
        }

        public void onTabSelected(Tab tab, FragmentTransaction ft) {
            ft.add(R.id.fragment_content, mFragment, mFragment.getText());
        }

        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
            ft.remove(mFragment);
        }

        public void onTabReselected(Tab tab, FragmentTransaction ft) {
            Toast.makeText(MainActivity.this, "Reselected!", Toast.LENGTH_SHORT).show();
        }
    }

    private class TabContentFragment extends Fragment {
        private String mText;

        public TabContentFragment(String text) {
            mText = text;
        }

        public String getText() {
            return mText;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View fragView = inflater.inflate(R.layout.action_bar_tab_content, container, false);

            TextView text = (TextView) fragView.findViewById(R.id.text);
            text.setText(mText);

            return fragView;
        }
    }
}

You may be getting many errors, we will be resolving all that in just a few minutes.

Now create an xml named “action_bar_tabs.xml” inside the res/layout folder and copy this code into it.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical">
    <FrameLayout android:id="@+id/fragment_content"
                 android:layout_width="match_parent"
                 android:layout_height="0dip"
                 android:layout_weight="1" />
    <LinearLayout android:layout_width="match_parent"
                  android:layout_height="0dip"
                  android:layout_weight="1"
                  android:orientation="vertical">
        <Button android:id="@+id/btn_add_tab"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Add Tab"
                android:onClick="onAddTab" />
        <Button android:id="@+id/btn_remove_tab"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Remove Tab"
                android:onClick="onRemoveTab" />
        <Button android:id="@+id/btn_toggle_tabs"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Toggle Tabs"
                android:onClick="onToggleTabs" />
        <Button android:id="@+id/btn_remove_all_tabs"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Remove All Tabs"
                android:onClick="onRemoveAllTabs" />
    </LinearLayout>
</LinearLayout>

Now create another xml for the tab content and named it “action_bar_tab_content.xml” and copy this code into it.

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/text"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" />

OK Done. Go on and run it.

ActionBar Tabs

ActionBar Tabs

ActionBar Tabs

ActionBar Tabs

Download Source code from here

Download.

2 thoughts on “Android Tutorials

  1. Punith

    This site is really heaven for developers who are either new to coding or experts, author is using such a sophisticated way to explain things easily. Thanks for your contribution to the field of technology.

    Reply

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