由网友(黙冩、吶慯)分享简介：这似乎是一个简单的事情，但我不能修复它，所以请帮助我。我有4个文件：It's seems like a simple thing to do, but I can't fix it, so please help me.I have 4 files :MainActivity.javaactivity_mai...

这似乎是一个简单的事情，但我不能修复它，所以请帮助我。 我有4个文件：

It's seems like a simple thing to do, but I can't fix it, so please help me. I have 4 files :

MainActivity.java
activity_main.xml
FragmentClass.java
frag_class.xml

frag_class.xml有TextView的，我想改变从MainActivity.java文本。 FragmentClass延伸片段，该片段中显示MainActivity FragmentClass有：

frag_class.xml has textView, I want to change the text from MainActivity.java. FragmentClass extends Fragment, this fragment is displayed in MainActivity FragmentClass has:

public void changeText(String text){
 TextView t = (TextView) this.getView().findViewById(R.id.tView);
 t.setText(text);
}

和在MainActivity我已经试过这样：

and in MainActivity I have tried this:

FragmentClass fc = new FragmentClass();
fc.changeText("some text");

但可悲的是这个code给我的NullPointerException在 fc.changeText（一些文本）; 我也试过直接从MainActivity改变文字：

But sadly this code gives me NullPointerException at fc.changeText("some text"); I've also tried changing the text directly from MainActivity with:

 TextView t = (TextView) this.getView().findViewById(R.id.tView);
 t.setText(text);

失败。 请帮我。

Fail. Please help me.

更新： 全部code在这里。 http://pastebin.com/NQBieFLi

Update: Full code here. http://pastebin.com/NQBieFLi

推荐答案

@Lalit的答案是正确的，但我看到，你不需要建立像fragment_obj.updateTextView功能（）;.我把我所有的观点是一流水平的对象，并能够直接更新的TextView。

@Lalit answer is correct but I see that you dont need to create a function like fragment_obj.updateTextView();. I set all my view as class level objects and was able to update the textview directly.

fragmentRegister.textViewLanguage.setText("hello mister how do you do");

请注意：如果需要执行多个动作，然后有一个功能是要走的路

Note: If you need to perform more than one action then having a function is the way to go.