关于父Activity更新UI

	TabHost myTabHost;
	Context c;
	private ActivityPage_101 activityOne;
	private ActivityPage_102 activityTwo;
	private ActivityPage_103 activityThree;
	private ActivityPage_104 activityFour;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.layout_tabhost);
		c = this;
		myTabHost = this.getTabHost();
		initTabHost(c,myTabHost,
				new TabHost.TabSpec[]{
					myTabHost.newTabSpec("a").setIndicator(composeLayout("我的任务", R.drawable.tab_weixin_pressed)).setContent(new Intent(c,ActivityPage_101.class)),
					myTabHost.newTabSpec("b").setIndicator(composeLayout("通讯录", R.drawable.tab_address_pressed)).setContent(new Intent(c,ActivityPage_102.class)),
					myTabHost.newTabSpec("c").setIndicator(composeLayout("查询", R.drawable.tab_find_frd_pressed)).setContent(new Intent(c,ActivityPage_103.class)),
					myTabHost.newTabSpec("d").setIndicator(composeLayout("我", R.drawable.tab_settings_pressed)).setContent(new Intent(c,ActivityPage_104.class))
				});
		initSubActivity();
	}
	
	public void initTabHost(final Context context,
			final TabHost tabHost, TabSpec[] tabSpecs) {

		for (TabSpec tabSpec : tabSpecs) {
			tabHost.addTab(tabSpec);
		}
		final TabWidget tabWidget = tabHost.getTabWidget();
		for (int i = 0; i < tabWidget.getChildCount(); i++) {
			tabWidget.getChildAt(i).getLayoutParams().height = zoom(context,50);
		}
		for (int i = tabWidget.getChildCount() - 1; i >= 0; i--) {
			tabHost.setCurrentTab(i);
		}
	}
	
	private void initSubActivity()
	{
		try {
			FrameLayout fl = myTabHost.getTabContentView();
			for (int i1 = 0; i1 < fl.getChildCount(); i1++) {
				View v = fl.getChildAt(i1);
				Object a = v.getContext();
				if (a instanceof ActivityPage_101) {
					activityOne = (ActivityPage_101) a;
				}
				if (a instanceof ActivityPage_102) {
					activityTwo = (ActivityPage_102) a;
				}
				if (a instanceof ActivityPage_103) {
					activityThree = (ActivityPage_103) a;
				}
				if (a instanceof ActivityPage_104) {
					activityFour = (ActivityPage_104) a;
				}
			}
		} catch (Exception ex) {
			//ActionTool.showException(c, ex);
		}
	}

<?xml version="1.0" encoding="utf-8"?>
<TabHost
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@android:id/tabhost" 
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
  	<LinearLayout android:orientation="vertical"
		android:layout_width="fill_parent" android:layout_height="fill_parent">
		<!-- 实现Tab标签的居底主要是通过设置属性 android:layout_weight="1" -->
		<!-- 还要注意FrameLayout标签的位置，要写在TabWidget标签的前面 -->
		<FrameLayout android:id="@android:id/tabcontent"
			android:layout_weight="1" android:layout_width="fill_parent"
			android:layout_height="fill_parent" />

		<TabWidget android:id="@android:id/tabs"
			android:layout_alignParentBottom="true" android:layout_width="fill_parent"
			android:layout_height="wrap_content" />
	</LinearLayout>
</TabHost>