Android学习笔记之ActionBar Item用法分析

本文实例讲述了Android ActionBar Item用法。分享给大家供大家参考，具体如下：

这里主要讲述ActionBar Item的使用方法。在手机上，按Menu键出现Menu菜单，但是在平板中可以把菜单放在ActionBar里面，放置的Item也比手机上多，下面详细介绍其用法：

1、在Androidmanifest.xml里面加上

<uses-sdk Android:minSdkVersion="11"/>

或者

<uses-sdk android:targetSdkVersion="11" />

要使版本号在3.0以上，这样系统就自动把Menu放在ActionBar上面。

2、准备一个menu.xml，以便加载。其实这就是一个传统的menu布局，只是多了android:showAsAction="ifRoom|withText"这个属性，ifRoom的意思就是说只要ActionBar上有空间，就把该Item显示出来，否则就坠在后面。

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:id="@+id/action_search"
     android:icon="@android:drawable/ic_menu_search"
     android:title="action_bar_search"
     android:showAsAction="ifRoom"
     android:actionViewClass="android.widget.SearchView" />
  <item android:id="@+id/action_add"
     android:icon="@android:drawable/ic_menu_add"
     android:title="action_bar_add" />
  <item android:id="@+id/action_edit"
     android:icon="@android:drawable/ic_menu_edit"
     android:showAsAction="always"
     android:title="action_bar_edit" />
  <item android:id="@+id/action_share"
     android:icon="@android:drawable/ic_menu_share"
     android:title="action_bar_share"
     android:showAsAction="ifRoom" />
  <item android:id="@+id/action_sort"
     android:icon="@android:drawable/ic_menu_sort_by_size"
     android:title="action_bar_sort"
     android:showAsAction="ifRoom">
    <menu>
      <item android:id="@+id/action_sort_size"
         android:icon="@android:drawable/ic_menu_sort_by_size"
         android:title="action_bar_sort_size"
         android:onClick="onSort" />
      <item android:id="@+id/action_sort_alpha"
         android:icon="@android:drawable/ic_menu_sort_alphabetically"
         android:title="action_bar_sort_alpha"
         android:onClick="onSort" />
    </menu>
  </item>
</menu>

3、Activity中的代码：

import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.SearchView;
import android.widget.SearchView.OnQueryTextListener;
import android.widget.TextView;
import android.widget.Toast;
/**
 * This demonstrates idiomatic usage of the Action Bar. The default Honeycomb theme
 * includes the action bar by default and a menu resource is used to populate the
 * menu data itself. If you'd like to see how these things work under the hood, see
 * ActionBarMechanics.
 */
public class ActionBarUsageActivity extends Activity implements OnQueryTextListener {
  TextView mSearchText;
  int mSortMode = -1;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mSearchText = new TextView(this);
    setContentView(mSearchText);
  }
  //和加载传统的menu一样，重写onCreateOptionsMenu方法
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.actions, menu);
    SearchView searchView = (SearchView) menu.findItem(R.id.action_search).getActionView();
    searchView.setOnQueryTextListener(this);
    return true;
  }
  @Override
  public boolean onPrepareOptionsMenu(Menu menu) {
    if (mSortMode != -1) {
      Drawable icon = menu.findItem(mSortMode).getIcon();
      menu.findItem(R.id.action_sort).setIcon(icon);
    }
    return super.onPrepareOptionsMenu(menu);
  }
  //和相应传统的menu一样，重写onOptionsItemSelected方法
  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    Toast.makeText(this, "Selected Item: " + item.getTitle(), Toast.LENGTH_SHORT).show();
    return true;
  }
  // This method is specified as an onClick handler in the menu xml and will
  // take precedence over the Activity's onOptionsItemSelected method.
  // See res/menu/actions.xml for more info.
  public void onSort(MenuItem item) {
    mSortMode = item.getItemId();
    // Request a call to onPrepareOptionsMenu so we can change the sort icon
    invalidateOptionsMenu();
  }
  // The following callbacks are called for the SearchView.OnQueryChangeListener
  // For more about using SearchView, see src/.../view/SearchView1.java and SearchView2.java
  public boolean onQueryTextChange(String newText) {
    newText = newText.isEmpty() ? "" : "Query so far: " + newText;
    mSearchText.setText(newText);
    return true;
  }
  public boolean onQueryTextSubmit(String query) {
    Toast.makeText(this, "Searching for: " + query + "...", Toast.LENGTH_SHORT).show();
    return true;
  }
}

这样，一个ActionBar Item的例子就顺利的完成了。

希望本文所述对大家Android程序设计有所帮助。