Android findViewById空指针[重复]

来自activity\u设置。xml

<EditText android:id="@+id/editText" android:text="text" />
<Button android:id="@+id/button" android:text="button"/>

来自MyActivity。Java语言

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_settings);
    this.findViewById(R.id.button).setOnClickListener(
        new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText txt = (EditText) view.findViewById(R.id.editText);
                Toast.makeText(view.getContext(),txt.getText(), Toast.LENGTH_SHORT).show();
           }
        });
...

如果我点击按钮

 java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference

只是为了测试,我试了试,成功了

@Override
public void onClick(View view) {
    EditText txt = (EditText) view.findViewById(R.id.editText);
    Toast.makeText(view.getContext(),txt.getText(),Toast.LENGTH_SHORT).show();
    }
}

我不明白为什么按钮可以,但editText为空。