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)

这个问题困扰了我好几天了。

先贴一段代码

//产品规格
		final TabHost tabHost = (TabHost) this.findViewById(android.R.id.tabhost);
		tabHost.setup(); //必须setup
		//如果不存在info，则添加一个空的tab, 否则会莫名其妙的报错
		//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(""))// 该ID必须位于layout里面
					.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()))// 该ID必须位于layout里面
					.setIndicator(view));
		}

如果

saleDetail.getInfoList() == 0   起初的时候不会创建tab

然后如果单击spinner 或者是弹出alert的时候 会报错，如上。。。。

通过测试， 发现如果tab个数大于1的时候 则不会报错

于是乎。。。 揣测跟tab有关 加上该段代码。 如果不存在的时候 默认加一个不可见的tab

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

、、、、、

至此问题解决