使用ActionBar实现Tab导航

为了使用ActionBar实现Tab导航，按如下步骤进行即可。

1.调用ActionBar的setNavigationMode(ActionBar.NAVIGATION_MODE_TABS)方法设置使用Tab导航方式。

2.调用ActionBar的addTab方法添加多个Tab标签，并为每个Tab标签添加事件监听。

Fragment相当于activity片段，通常使用单独的activity组合多个fragment，这样既可以在一个activity创建多个用户界面，又可以让多个activity复用同一个fragment，总之，fragment相当于activity的模块化区域。

fragment有自己的生命周期，可以接受处理属于它自身的事件，并允许activity运行期间动态的添加删除fragment。

fragment允许定义自己的布局，也可以通过生命周期回调方法定义自己的行为，这一点非常像activity。

实例的布局文件：

StandardWidget eslayout abnavigation.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" 
    android:id="@+id/container"
    
    >
    

</LinearLayout>

activity代码:

package com.example.standardwidget;


import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBar.TabListener;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar.Tab;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

public class MyActionBarActivity extends ActionBarActivity implements
        TabListener {

    private static final String SELECTED_ITEM = "selected_item";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        setContentView(R.layout.tabnavigation);
        // 设置是否显示app的图标
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        // 设置是否将app图标转变成成可点击的按钮
        getSupportActionBar().setHomeButtonEnabled(true);

        getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        getSupportActionBar().addTab(
                getSupportActionBar().newTab().setText("第一页")
                        .setTabListener(this));

        getSupportActionBar().addTab(
                getSupportActionBar().newTab().setText("第二页")
                        .setTabListener(this));

        getSupportActionBar().addTab(
                getSupportActionBar().newTab().setIcon(R.drawable.p13)
                        .setText("第三页").setTabListener(this));
        
        
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onRestoreInstanceState(savedInstanceState);
        
        if (savedInstanceState.containsKey(SELECTED_ITEM)) {
        //选中前面保存的索引对应的fragment页
            getSupportActionBar().setSelectedNavigationItem(
                    savedInstanceState.getInt(SELECTED_ITEM));
        }

    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        // TODO Auto-generated method stub
        super.onSaveInstanceState(outState);
        //将当前选中的fragment页的索引保存到bundle中
        outState.putInt(SELECTED_ITEM, getSupportActionBar()
                .getSelectedNavigationIndex());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        // 为ActionBar扩展菜单项
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main_activity_actions, menu);
        return super.onCreateOptionsMenu(menu);

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        // 处理动作按钮的点击事件
        switch (item.getItemId()) {
        case R.id.action_search:
            Toast.makeText(this, "openSearch", 2000).show();
            return true;
        case R.id.action_settings:

            Toast.makeText(this, "openSettings", 2000).show();
            return true;

        case android.R.id.home:
            Toast.makeText(this, "App Icon", 2000).show();
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

    @Override
    public void onTabReselected(Tab arg0, FragmentTransaction arg1) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onTabSelected(Tab arg0, FragmentTransaction arg1) {
        // TODO Auto-generated method stub
        Fragment fragment = new DummyFragment();
        //用于向fragment传入参数
        Bundle argsBundle = new Bundle();
        argsBundle.putInt(DummyFragment.ARG_SELECTION_NUMBER, arg0.getPosition()+1);
        //向fragment传入参数
        fragment.setArguments(argsBundle);
        //获取fragmenttransaction对象
        FragmentTransaction fTransaction = getSupportFragmentManager().beginTransaction();
        //使用fragment代替该activity中的container组件
        fTransaction.replace(R.id.container, fragment);
        fTransaction.commit();
    }

    @Override
    public void onTabUnselected(Tab arg0, FragmentTransaction arg1) {
        // TODO Auto-generated method stub

    }
    
    

}

fragment代码:

package com.example.standardwidget;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class DummyFragment extends Fragment {
    
    protected static final String ARG_SELECTION_NUMBER ="selection_number";
    //该方法的返回值就是该fragment显示的view组件
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        TextView textView = new TextView(getActivity());
        textView.setGravity(Gravity.START);
        //获取创建该fragment时传入的参数bundle
        Bundle args = getArguments();
        //设置TextView显示的文本
        textView.setText(args.getInt(ARG_SELECTION_NUMBER)+"");
        textView.setTextSize(30);
        
        
        return textView;
    }
}

运行该实例，效果如图：