Android UI之Tab(TabActivity+TabHost實現)

Tab標籤頁是UI設計時經常使用的UI控件，可以實現多個分頁之間的快速切換，每個分頁可以顯示不同的內容。

TabHost相當於瀏覽器中標籤頁分佈的集合，而Tabspec則相當於瀏覽器中的每一個分頁面。在Android中，每一個TabSpec分佈可以是一個組件，也可以是一個佈局，然後將每一個分頁裝入TabHost中，TabHost即可將其中的每一個分頁一併顯示出來。

使用Tab標籤頁的一般步驟：
首先要設計所有的分頁的界面佈局
Activity繼承TabActivity
調用TabActivity的getTabHost()方法獲得TabHost對象
通過TabHost創建並添加Tab

實例：TabDemo
運行效果：

代碼清單：
佈局文件：tab.xml

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

    <TextView android:id="@+id/view1"
        android:background="@drawable/blue"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="這裏是Tab1裏的內容。"/>

    <TextView android:id="@+id/view2"
        android:background="@drawable/red"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="這裏是Tab2"/>

    <TextView android:id="@+id/view3"
        android:background="@drawable/green"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="Tab3"/>

</FrameLayout>

Java源代碼文件：MainActivity.java

package com.rainsong.tabdemo;

import android.app.TabActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.widget.TabHost;

public class MainActivity extends TabActivity
{
    TabHost mTabHost;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        mTabHost = getTabHost();
        LayoutInflater.from(this).inflate(R.layout.tab,
                mTabHost.getTabContentView(), true);
        mTabHost.addTab(mTabHost.newTabSpec("tab1").setIndicator("Tab1")
                .setContent(R.id.view1));
        mTabHost.addTab(mTabHost.newTabSpec("tab3").setIndicator("Tab2")
                .setContent(R.id.view2));
        mTabHost.addTab(mTabHost.newTabSpec("tab3").setIndicator("Tab3")
                .setContent(R.id.view3));
    }
}

API知識點
public class
TabActivity
extends ActivityGroup

TabHost  getTabHost() 
Returns the TabHost the activity is using to host its tabs. 

public abstract class
LayoutInflater
extends Object

Class Overview
Instantiates a layout XML file into its corresponding View objects.

static LayoutInflater  from(Context context) 
Obtains the LayoutInflater from the given context. 

View  inflate(int resource, ViewGroup root, boolean attachToRoot) 
Inflate a new view hierarchy from the specified xml resource. 

public class
TabHost
extends FrameLayout
implements ViewTreeObserver.OnTouchModeChangeListener

Known Direct Subclasses 
FragmentTabHost  

Class Overview

Container for a tabbed window view. This object holds two children: a set of tab labels that the user clicks to select a specific tab, and a FrameLayout object that displays the contents of that page.

FrameLayout  getTabContentView() 
Get the FrameLayout which holds tab content  

void  addTab(TabHost.TabSpec tabSpec) 
Add a tab. 

TabHost.TabSpec  newTabSpec(String tag) 
Get a new TabHost.TabSpec associated with this tab host. 

public class
TabHost.TabSpec
extends Object

Class Overview
A tab has a tab indicator, content, and a tag that is used to keep track of it. 
This builder helps choose among these options. 
For the tab indicator, your choices are: 
1) set a label 
2) set a label and an icon 
For the tab content, your choices are: 
1) the id of a View 
2) a TabHost.TabContentFactory that creates the View content. 
3) an Intent that launches an Activity. 

TabHost.TabSpec  setIndicator(CharSequence label) 
Specify a label as the tab indicator. 


TabHost.TabSpec  setContent(int viewId) 

Specify the id of the view that should be used as the content of the tab.