使用Handler产生空指针异常的问题
我想用Handler刷新TabActivity中TextView里的文本，通过点击菜单项刷新，可为什么总是报空指针异常

关键代码：

Java code

          private class MyHandler extends Handler {        public MyHandler(Looper looper){            super(looper);        }                @Override        public void handleMessage(Message msg) {            switch (msg.what) {            case SET:                Test.this.text1_1_2.setText(msg.obj.toString());                            }            super.handleMessage(msg);        }            };    @Override    public boolean onCreateOptionsMenu(Menu menu) {        menu.add(0, 1, 1, R.string.menu1);        return super.onCreateOptionsMenu(menu);    }    @Override    public boolean onMenuItemSelected(int featureId, MenuItem item) {        if (item.getItemId() == 1) {            Looper looper = Looper.myLooper();            MyHandler myHandler = new MyHandler(looper);            myHandler.removeMessages(0);            String data = "ABCDE";            Message msg = myHandler.obtainMessage(SET,1,1,data);            myHandler.sendMessage(msg);                    }        return super.onMenuItemSelected(featureId, item);            }

错误信息：

04-13 09:02:22.404: E/AndroidRuntime(919): FATAL EXCEPTION: main
04-13 09:02:22.404: E/AndroidRuntime(919): java.lang.NullPointerException
04-13 09:02:22.404: E/AndroidRuntime(919): at zzx.Android.Test$MyHandler.handleMessage(Test.java:108)
04-13 09:02:22.404: E/AndroidRuntime(919): at android.os.Handler.dispatchMessage(Handler.java:99)
04-13 09:02:22.404: E/AndroidRuntime(919): at android.os.Looper.loop(Looper.java:123)
04-13 09:02:22.404: E/AndroidRuntime(919): at android.app.ActivityThread.main(ActivityThread.java:4627)
04-13 09:02:22.404: E/AndroidRuntime(919): at java.lang.reflect.Method.invokeNative(Native Method)
04-13 09:02:22.404: E/AndroidRuntime(919): at java.lang.reflect.Method.invoke(Method.java:521)
04-13 09:02:22.404: E/AndroidRuntime(919): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-13 09:02:22.404: E/AndroidRuntime(919): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-13 09:02:22.404: E/AndroidRuntime(919): at dalvik.system.NativeStart.main(Native Method)




[解决办法]
查一查ext1_1_2 有没有
[解决办法]
text1_1_2.setText(msg.obj.toString());
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text1_1_2 或 msg.obj 为Null,提示说的很清楚了啊