TabHost与RadioGroup结合完成的菜单

效果图：   首先看布局文件： "1.0" encoding= "UTF-8" ?> "@android:id/tabhost" android:layout_width= "fill_parent" android:layout_height= "fill_parent" xmlns:android= "http://schemas.android.com/apk/res/android" > android:orientation= "vertical" android:layout_width= "fill_parent" android:layout_height= "fill_parent" > android:id= "@android:id/tabcontent" android:layout_width= "fill_parent" android:layout_height= "0.0dip" android:layout_weight= "1.0" /> android:id= "@android:id/tabs" android:visibility= "gone" android:layout_width= "fill_parent" android:layout_height= "wrap_content" android:layout_weight= "0.0" /> 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" > android:id= "@+id/radio_button0" android:tag= "radio_button0" android:layout_marginTop= "2.0dip" android:text= "@string/alarm" android:drawableTop= "@drawable/icon_1" style= "@style/main_tab_bottom" /> android:id= "@+id/radio_button1" android:tag= "radio_button1" android:layout_marginTop= "2.0dip" android:text= "@string/message" android:drawableTop= "@drawable/icon_2" style= "@style/main_tab_bottom" /> android:id= "@+id/radio_button2" android:tag= "radio_button2" android:layout_marginTop= "2.0dip" android:text= "@string/photo" android:drawableTop= "@drawable/icon_3" style= "@style/main_tab_bottom" /> android:id= "@+id/radio_button3" android:tag= "radio_button3" android:layout_marginTop= "2.0dip" android:text= "@string/music" android:drawableTop= "@drawable/icon_4" style= "@style/main_tab_bottom" /> android:id= "@+id/radio_button4" android:tag= "radio_button4" android:layout_marginTop= "2.0dip" android:text= "@string/setting" android:drawableTop= "@drawable/icon_5" style= "@style/main_tab_bottom" /> 需要注意的是，如果用TabHost这个控件，其中有几个ID是必须这么写的，android:id="@android:id/tabhost   ；android:id="@android:id/tabcontent" ；android:id="@android:id/tabs" ；之所以要这么写是因为在TabHost这个类中。需要实例化上述这个ID的控件。看源码：  在TabActivity中有么个方法：  @Override public void onContentChanged() { super .onContentChanged(); mTabHost = (TabHost) findViewById(com.android.internal.R.id.tabhost); if (mTabHost == null ) { throw new RuntimeException( "Your content must have a TabHost whose id attribute is " + "'android.R.id.tabhost'" ); } mTabHost.setup(getLocalActivityManager()); } private void ensureTabHost() { if (mTabHost == null ) { this .setContentView(com.android.internal.R.layout.tab_content); } } 当内容发生改变时它会调用这个方法，来更新列表或者其他视图，而这个方法中需要实例化TabHost，所以必须通过ID为tabhost实例化。  再看看TabHost这个类中， public void setup() { mTabWidget = (TabWidget) findViewById(com.android.internal.R.id.tabs); if (mTabWidget == null ) { throw new RuntimeException( "Your TabHost must have a TabWidget whose id attribute is 'android.R.id.tabs'" ); } // KeyListener to attach to all tabs. Detects non-navigation keys // and relays them to the tab content. mTabKeyListener = new OnKeyListener() { public boolean onKey(View v, int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_DPAD_CENTER: case KeyEvent.KEYCODE_DPAD_LEFT: case KeyEvent.KEYCODE_DPAD_RIGHT: case KeyEvent.KEYCODE_DPAD_UP: case KeyEvent.KEYCODE_DPAD_DOWN: case KeyEvent.KEYCODE_ENTER: return false ; } mTabContent.requestFocus(View.FOCUS_FORWARD); return mTabContent.dispatchKeyEvent(event); } }; mTabWidget.setTabSelectionListener( new TabWidget.OnTabSelectionChanged() { public void onTabSelectionChanged( int tabIndex, boolean clicked) { setCurrentTab(tabIndex); if (clicked) { mTabContent.requestFocus(View.FOCUS_FORWARD); } } }); mTabContent = (FrameLayout) findViewById(com.android.internal.R.id.tabcontent); if (mTabContent == null ) { throw new RuntimeException( "Your TabHost must have a FrameLayout whose id attribute is " + "'android.R.id.tabcontent'" ); } } 这个方法，是在增加选项卡之前由系统调用。在这个方法中需要通过tabs 这个ID实例化一个TabWidget，通过tabcontent这个ID实例化一个FrameLayout，用来放置选项卡内容。所以这两个ID也是固定的。  在上述布局文件中隐藏了系统默认的Widget，取而代之的是带有图片的Button。  看一下主要代码：  package com.iteye.androidtoast; import android.app.TabActivity; import android.content.Intent; import android.os.Bundle; import android.widget.RadioGroup; import android.widget.RadioGroup.OnCheckedChangeListener; import android.widget.TabHost; public class MainActivity extends TabActivity implements OnCheckedChangeListener{ /** Called when the activity is first created. */ private TabHost mHost; private RadioGroup radioderGroup; @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.maintabs); //实例化TabHost mHost= this .getTabHost(); //添加选项卡 mHost.addTab(mHost.newTabSpec( "ONE" ).setIndicator( "ONE" ) .setContent( new Intent( this ,OneActivity. class ))); mHost.addTab(mHost.newTabSpec( "TWO" ).setIndicator( "TWO" ) .setContent( new Intent( this ,TwoActivity. class ))); mHost.addTab(mHost.newTabSpec( "THREE" ).setIndicator( "THREE" ) .setContent( new Intent( this ,ThreeActivity. class ))); mHost.addTab(mHost.newTabSpec( "FOUR" ).setIndicator( "FOUR" ) .setContent( new Intent( this ,FourActivity. class ))); mHost.addTab(mHost.newTabSpec( "FIVE" ).setIndicator( "FIVE" ) .setContent( new Intent( this ,FiveActivity. class ))); radioderGroup = (RadioGroup) findViewById(R.id.main_radio); radioderGroup.setOnCheckedChangeListener( this ); } @Override public void onCheckedChanged(RadioGroup group, int checkedId) { switch (checkedId){ case R.id.radio_button0: mHost.setCurrentTabByTag( "ONE" ); break ; case R.id.radio_button1: mHost.setCurrentTabByTag( "TWO" ); break ; case R.id.radio_button2: mHost.setCurrentTabByTag( "THREE" ); break ; case R.id.radio_button3: mHost.setCurrentTabByTag( "FOUR" ); break ; case R.id.radio_button4: mHost.setCurrentTabByTag( "FIVE" ); break ; } } }