ActionBar示例代码 (二) Android开发技术

   ActionBar相关的示例代码第二部分分为两种，作为Android 3.0的重要特性我们直接看代码:

  一、使用菜单资源构造

  public class ActionBarMechanics extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
     
        menu.add("Normal item");

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

 二、作为Tab切换Fragment

public class ActionBarTabs 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();
        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();
    }
 
    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(ActionBarTabs.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;
        }

    }
}

涉及的布局文件action_bar_tabs.xml代码为

<?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="@string/btn_add_tab"
                android:onClick="onAddTab" />
        <Button android:id="@+id/btn_remove_tab"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/btn_remove_tab"
                android:onClick="onRemoveTab" />
        <Button android:id="@+id/btn_toggle_tabs"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/btn_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="@string/btn_remove_all_tabs"
                android:onClick="onRemoveAllTabs" />
    </LinearLayout>
</LinearLayout>

涉及布局文件action_bar_tab_content.xml的代码为

<?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" />