【Android】Actionbar下拉导航

直接上代码。

activity类：

package com.zzj.ui.actionbardemo;

import android.app.ActionBar;
import android.app.ActionBar.OnNavigationListener;
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.ArrayAdapter;
import android.widget.TextView;

import com.zzj.ui.R;

public class ActionbarListNavigation extends Activity implements
        OnNavigationListener {
    private ActionBar actionBar;

    private Fragment aFragment;
    private Fragment bFragment;
    private Fragment cFragment;

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

        actionBar = getActionBar();
        // 开启下拉导航模式
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

        /*
         *
         * 切屏（横屏竖屏切换）时Activity会被销毁，
         *
         * 但是Fragment会备份并且重新加载（调用onCreateView()方法）。
         */
        FragmentTransaction fragmentTransaction = getFragmentManager()
                .beginTransaction();
        aFragment = getFragmentManager().findFragmentByTag("aFragment");
        if (aFragment == null) {
            aFragment = new MyFragment();
            fragmentTransaction.add(R.id.fragment_container, aFragment,
                    "aFragment");
        }
        bFragment = getFragmentManager().findFragmentByTag("bFragment");
        if (bFragment == null) {
            bFragment = new MyFragment();
            fragmentTransaction.add(R.id.fragment_container, bFragment,
                    "bFragment");
        }
        cFragment = getFragmentManager().findFragmentByTag("cFragment");
        if (cFragment == null) {
            cFragment = new MyFragment();
            fragmentTransaction.add(R.id.fragment_container, cFragment,
                    "cFragment");
        }
        System.out.println("aFragment:" + aFragment.hashCode());
        System.out.println("bFragment:" + bFragment.hashCode());
        System.out.println("cFragment:" + cFragment.hashCode());
        fragmentTransaction.commit();

        actionBar.setListNavigationCallbacks(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, android.R.id.text1,
                new String[] { "聊天", "发现", "通讯录" }), this);
    }

    @Override
    public boolean onNavigationItemSelected(int itemPosition, long itemId) {
        System.out.println(itemPosition);
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        switch (itemPosition) {
        case 0:
            ft.show(aFragment);
            ft.hide(bFragment);
            ft.hide(cFragment);
            break;
        case 1:
            ft.show(bFragment);
            ft.hide(aFragment);
            ft.hide(cFragment);
            break;
        case 2:
            ft.show(cFragment);
            ft.hide(bFragment);
            ft.hide(aFragment);
            break;
        default:
            break;
        }
        ft.commit();
        return true;
    }

    public static class MyFragment extends Fragment {

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            System.out.println(container.getTag() + "_" + this.getTag() + "_"
                    + this.hashCode());
            View view = inflater
                    .inflate(R.layout.fragmenttab, container, false);
            TextView textView = (TextView) view
                    .findViewById(R.id.fragment_textview);
            textView.setText("fragment_" + this.hashCode());
            return view;
        }
    }
}

布局文件actionbar_listnavigation_activity.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:tag="fragment_container" >

</LinearLayout>

fragment布局文件fragmenttab.xml：

<?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" >

    <TextView
        android:id="@+id/fragment_textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

效果：

 

 

需要注意的是，下拉导航并不一定需要fragment，这一点与Tab导航不同。