妙用TabHost

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版本

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正文

　　一、效果图

　　　　

　　　　红色部分是本文要实现的目标。

　　二、实现

　　　　maintabs.xml

xml version="1.0" encoding="UTF-8" ?>
< TabHost android:id ="@android:id/tabhost" android:layout_width ="fill_parent" android:layout_height ="fill_parent"
  xmlns:android ="http://schemas.android.com/apk/res/android" >
    < LinearLayout android:orientation ="vertical" android:layout_width ="fill_parent" android:layout_height ="fill_parent" >
        < FrameLayout android:id ="@android:id/tabcontent" android:layout_width ="fill_parent" android:layout_height ="0.0dip" android:layout_weight ="1.0" />
        < TabWidget android:id ="@android:id/tabs" android:visibility ="gone" android:layout_width ="fill_parent" android:layout_height ="wrap_content" android:layout_weight ="0.0" />
        < RadioGroup android:gravity ="center_vertical" android:layout_gravity ="bottom" android:orientation ="horizontal" android:id ="@id/main_radio" android:background ="@drawable/maintab_toolbar_bg" android:layout_width ="fill_parent" android:layout_height ="wrap_content" >
            < RadioButton   android:text ="@string/main_home" android:checked ="true" android:id ="@+id/radio_button0" android:layout_marginTop ="2.0dip" android:drawableTop ="@drawable/icon_1_n" style ="@style/main_tab_bottom" />
            < RadioButton android:id ="@+id/radio_button1" android:layout_marginTop ="2.0dip" android:text ="@string/main_news" android:drawableTop ="@drawable/icon_2_n" style ="@style/main_tab_bottom" />
            < RadioButton android:id ="@+id/radio_button2" android:layout_marginTop ="2.0dip" android:text ="@string/main_my_info" android:drawableTop ="@drawable/icon_3_n" style ="@style/main_tab_bottom" />
            < RadioButton android:id ="@+id/radio_button3" android:layout_marginTop ="2.0dip" android:text ="@string/menu_search" android:drawableTop ="@drawable/icon_4_n" style ="@style/main_tab_bottom" />
            < RadioButton android:id ="@+id/radio_button4" android:layout_marginTop ="2.0dip" android:text ="@string/more" android:drawableTop ="@drawable/icon_5_n" style ="@style/main_tab_bottom" />
        RadioGroup >
    LinearLayout >
TabHost >

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　　　　styles.xml

    < style name ="main_tab_bottom" >
        < item name ="android:textSize" > @dimen/bottom_tab_font_size item >
        < item name ="android:textColor" > #ffffffff item >
        < item name ="android:ellipsize" > marquee item >
        < item name ="android:gravity" > center_horizontal item >
        < item name ="android:background" > @drawable/home_btn_bg item >
        < item name ="android:paddingTop" > @dimen/bottom_tab_padding_up item >
        < item name ="android:layout_width" > fill_parent item >
        < item name ="android:layout_height" > wrap_content item >
        < item name ="android:button" > @null item >
        < item name ="android:singleLine" > true item >
        < item name ="android:drawablePadding" > @dimen/bottom_tab_padding_drawable item >
        < item name ="android:layout_weight" > 1.0 item >
    style >

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　　　　home_btn_bg.xml

        < selector
          xmlns:android ="http://schemas.android.com/apk/res/android" >
            < item android:state_focused ="true" android:state_enabled ="true" android:state_pressed ="false" android:drawable ="@drawable/home_btn_bg_s" />
            < item android:state_enabled ="true" android:state_pressed ="true" android:drawable ="@drawable/home_btn_bg_s" />
            < item android:state_enabled ="true" android:state_checked ="true" android:drawable ="@drawable/home_btn_bg_d" />
            < item android:drawable ="@drawable/transparent" />
        selector >

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　　　　代码说明：

　　　　　　　　1.　　需要注意的是他这里把TabWidget的Visibility设置成了gone!也就是默认难看的风格不见了：，取而代之的是5个带风格的单选按钮.

　　　　　　　　2.　　注意为单选按钮设置的style，其中最重要的是为其background设置了home_btn_bg.xml，也就是自定义了选中效果。

　　　　Java文件

public class MainTabActivity extends TabActivity implements
        OnCheckedChangeListener {

    private TabHost mHost;
    private Intent mMBlogIntent;
    private Intent mMoreIntent;
    private Intent mInfoIntent;
    private Intent mSearchIntent;
    private Intent mUserInfoIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.maintabs);

        // ~~~~~~~~~~~~ 初始化
        this .mMBlogIntent = new Intent( this , HomeListActivity. class );
        this .mSearchIntent = new Intent( this , SearchSquareActivity. class );
        this .mInfoIntent = new Intent( this , MessageGroup. class );
        this .mUserInfoIntent = new Intent( this , MyInfoActivity. class );
        this .mMoreIntent = new Intent( this , MoreItemsActivity. class );

        initRadios();
       
        setupIntent();
    }

    /**
     * 初始化底部按钮
     */
    private void initRadios() {
         ((RadioButton) findViewById(R.id.radio_button0)).setOnCheckedChangeListener( this );
         ((RadioButton) findViewById(R.id.radio_button1)).setOnCheckedChangeListener( this );
         ((RadioButton) findViewById(R.id.radio_button2)).setOnCheckedChangeListener( this );
         ((RadioButton) findViewById(R.id.radio_button3)).setOnCheckedChangeListener( this );
         ((RadioButton) findViewById(R.id.radio_button4)).setOnCheckedChangeListener( this );
    }

    /**
     * 切换模块
     */
    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        if (isChecked) {
            switch (buttonView.getId()) {
            case R.id.radio_button0:
                this .mHost.setCurrentTabByTag( " mblog_tab " );
                break ;
            case R.id.radio_button1:
                this .mHost.setCurrentTabByTag( " message_tab " );
                break ;
            case R.id.radio_button2:
                this .mHost.setCurrentTabByTag( " userinfo_tab " );
                break ;
            case R.id.radio_button3:
                this .mHost.setCurrentTabByTag( " search_tab " );
                break ;
            case R.id.radio_button4:
                this .mHost.setCurrentTabByTag( " more_tab " );
                break ;
            }
        }
    }

    private void setupIntent() {
        this .mHost = getTabHost();
        TabHost localTabHost = this .mHost;

        localTabHost.addTab(buildTabSpec( " mblog_tab " , R.string.main_home,
                R.drawable.icon_1_n, this .mMBlogIntent));

        localTabHost.addTab(buildTabSpec( " message_tab " , R.string.main_news,
                R.drawable.icon_2_n, this .mInfoIntent));

        localTabHost.addTab(buildTabSpec( " userinfo_tab " , R.string.main_my_info,
                R.drawable.icon_3_n, this .mUserInfoIntent));

        localTabHost.addTab(buildTabSpec( " search_tab " , R.string.menu_search,
                R.drawable.icon_4_n, this .mSearchIntent));

        localTabHost.addTab(buildTabSpec( " more_tab " , R.string.more,
                R.drawable.icon_5_n, this .mMoreIntent));

    }

    private TabHost.TabSpec buildTabSpec(String tag, int resLabel, int resIcon,
            final Intent content) {
        return this .mHost
                .newTabSpec(tag)
                .setIndicator(getString(resLabel),
                        getResources().getDrawable(resIcon))
                .setContent(content);
    }

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　代码说明

　　　　　　1.　　由于TabWidget被隐藏，所以相关的事件也会无效，这里取巧用RadioGroup与RadioButton的特性来处理切换，然后监听事件调用setCurrentTabByTag来切换Activity。

　　　　　　2.　　注意即使TabWidget被隐藏，也要为其设置indicator，否则会保持。

　　三、总结

　　　　在这之前如果要做这种效果我恐怕第一时间就会想到用ActivityGroup来做，主要是因为TabHost的TabWidget非常难看，用起来也不方便。其实从源码可以看出，TabActivity也是继承自ActivityGroup，这里结合了单选按钮和TabHost，各取其长，有时间可以专门写一个这样的自定义控件:)