低版本系统兼容的ActionBar（四）添加Tab+添加自定义的Tab视图+Fragment

在ActionBar中添加Tab是很有用的技巧。在support V7库的支持下，我们几乎可以用和之前一样的方式来添加Tab，对于Tab来说，我们可以和MenuItem一样，给他定义自己的视图。我这里定义了个进度条，主要是来说明这个问题。本系列的博文也将接近尾声了，后面就是个定义ActionBar样式和一个仿照微信的实例，顺便讲解下Fragment和ViewPager的用法。

activity_main.xml（定义了一个FrameLayout来准备存放Fragment）

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.kale.actionbar03.MainActivity" >

    <FrameLayout
        android:id="@+id/container_id"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

tab_custom_view.xml（自定义的Tab视图）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ProgressBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:indeterminate="true"/>
</LinearLayout>

MainActivity.java

package com.kale.actionbar03;

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.Tab;
import android.support.v7.app.ActionBarActivity;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity implements ActionBar.TabListener{
    ActionBar actionBar;
    private static final String SELECTED_ITEM = "selected_item";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        actionBar = getSupportActionBar();
  
        //actionbar.setDisplayShowHomeEnabled(false);
        //actionbar.setDisplayShowTitleEnabled(false);//定义这两行后就会没有标题栏，只有tab栏了
        
        //设定有Tab
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        ActionBar.Tab tab;
        //开始添加Tab
        for (int i = 1; i <= 3; i++) {
            tab = actionBar.newTab();
            tab.setText("Tab " + i);
            tab.setTabListener(this);
            actionBar.addTab(tab);
        }
        tab = actionBar.newTab();
        tab.setCustomView(R.layout.tab_custom_view);
        tab.setText("x");
        tab.setTabListener(this);
        actionBar.addTab(tab);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        if (savedInstanceState.containsKey(SELECTED_ITEM)) {
            //选中前面保存的索引对应的Fragment页
            actionBar.setSelectedNavigationItem(savedInstanceState.getInt(SELECTED_ITEM));
        }
    }
    
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        //将当前选中的fragment页的索引保存到Bundle中
        outState.putInt(SELECTED_ITEM, actionBar.getSelectedNavigationIndex());
        super.onSaveInstanceState(outState);

    }
    
    /* 
     * @see android.support.v7.app.ActionBar.TabListener#onTabReselected(android.support.v7.app.ActionBar.Tab, android.support.v4.app.FragmentTransaction)
     * Tab再次被选中的时候执行的方法
     */
    @Override
    public void onTabReselected(Tab tab, FragmentTransaction transaction) {
        
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction transaction) {
        Toast.makeText(getApplicationContext(), tab.getText(), 0).show();
        //创建一个新的Fragment的对象
        Fragment fragment = new DummyFragment();
        //创建一个Bundle对象，用于向Fragment传入参数
        Bundle bundle = new Bundle();
        bundle.putInt(DummyFragment.BUNDLE_SECTION_NUMBER, tab.getPosition()+1);
        //向Fragment传入参数
        fragment.setArguments(bundle);
        
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        //使用fragment
        ft.replace(R.id.container_id, fragment);
        ft.commit();
    } 

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction transaction) {
    }



}

DummyFragment.java

package com.kale.actionbar03;

import android.os.Bundle;
import android.support.annotation.Nullable;
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 {

    public static final String BUNDLE_SECTION_NUMBER = "section_number";

    // 该返回值就是这个Fragment显示的view组件
    @Override
    public View onCreateView(LayoutInflater inflater,
            @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        TextView textView = new TextView(getActivity());
        textView.setGravity(Gravity.CENTER);
        // 获取创建该Fragment时传入的参数的Bundle
        Bundle bundle = getArguments();
        textView.setText("Fragment 0" + bundle.getInt(BUNDLE_SECTION_NUMBER));
        textView.setTextSize(50);
        return textView;
    }
}