ActionBarMechanics.java

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The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...

/*
 * Copyright (C) 2010 The Android开源工程
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.apis.app;

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

/**
 * This demonstrates the basics of the Action Bar and how it interoperates with the
 * standard options menu. This demo is for informative purposes only; see ActionBarUsage for
 * an example of using the Action Bar in a more idiomatic manner.
 */
public class ActionBarMechanics extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // The Action Bar is a window feature. The feature must be requested
        // before setting a content view. Normally this is set automatically
        // by your Activity's theme in your manifest. The provided system
        // theme Theme.WithActionBar enables this for you. Use it as you would
        // use Theme.NoTitleBar. You can add an Action Bar to your own themes
        // by adding the element <item name="android:windowActionBar">true</item>
        // to your style definition.
        getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Menu items default to never show in the action bar. On most devices this means
        // they will show in the standard options menu panel when the menu button is pressed.
        // On xlarge-screen devices a "More" button will appear in the far right of the
        // Action Bar that will display remaining items in a cascading menu.
        menu.add("Normal item");

        MenuItem actionItem = menu.add("Action Button");

        // Items that show as actions should favor the "if room" setting, which will
        // prevent too many buttons from crowding the bar. Extra items will show in the
        // overflow area.
        actionItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);

        // Items that show as actions are strongly encouraged to use an icon.
        // These icons are shown without a text description, and therefore should
        // be sufficiently descriptive on their own.
        actionItem.setIcon(android.R.drawable.ic_menu_share);

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Toast.makeText(this, "Selected Item: " + item.getTitle(), Toast.LENGTH_SHORT).show();
        return true;
    }
}