java.lang.NullPointerException at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:32

01-01 17:29:35.613: ERROR/AndroidRuntime(23590): java.lang.NullPointerException
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:321)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:321)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:661)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1819)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.os.Looper.loop(Looper.java:123)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at android.app.ActivityThread.main(ActivityThread.java:4363)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at java.lang.reflect.Method.invokeNative(Native Method)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at java.lang.reflect.Method.invoke(Method.java:521)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
01-01 17:29:35.613: ERROR/AndroidRuntime(23590):     at dalvik.system.NativeStart.main(Native Method)

この問題は私を何日も困らせた. 
まずコードを貼り付けます

// 
		final TabHost tabHost = (TabHost) this.findViewById(android.R.id.tabhost);
		tabHost.setup(); // setup
		// info， tab,  
		//java.lang.NullPointerException at android.widget.TabHost.dispatchWindowFocusChanged(TabHost.java:321)
		if(saleDetail.getInfoList().size() == 0){
			TextView view = new TextView(context);
			tabHost.addTab(tabHost.newTabSpec("")
					.setContent(new TabFacroty(""))//  ID layout 
					.setIndicator(view));
			tabHost.getTabWidget().setVisibility(View.GONE);
			return;
		}
		for(GoodsInfoBean info : saleDetail.getInfoList()){
			TextView view = new TextView(context);
			view.setLayoutParams(new LinearLayout.LayoutParams(-2, -2));
			view.setText(info.getTitle());
			view.setFocusable(true);
			view.setFocusableInTouchMode(true);
			view.setGravity(Gravity.CENTER);
			view.setTextColor(context.getResources().getColor(R.color.sale_tab_default));
			view.setBackgroundResource(R.drawable.sale_detail_spec_selector);
			tabHost.addTab(tabHost.newTabSpec("")
					.setContent(new TabFacroty(info.getAlt()))//  ID layout 
					.setIndicator(view));
		}

場合

saleDetail.getInfoList() == 0    tab

次にspinnerをクリックしたりalertをポップアップしたりすると、上記のようにエラーが表示されます...
テストによりtab個数が1より大きい場合はエラーが報告されないことが分かった
それで...tabと関係があると推測してこのセグメントコードを加える.存在しない場合はデフォルトで非表示のtabを追加します

if(saleDetail.getInfoList().size() == 0){

、、、、、
これで問題を解決する