android - 获取错误 "cannot resolve findViewById(int)'

Question

我有一个主要 Activity ，当我按下一个按钮时，我被导航到一个滑动选项卡 View 。现在我想在这些选项卡中有一个 Clickable Button 并在按下按钮时呈现 toast 。这是我使用的代码:

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class laundry extends Fragment {
Button btn_service;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    return inflater.inflate(R.layout.activity_laundry, container,false);
    btn_service = (Button) findViewById(R.id.btn_service);
    btn_service.setOnClickListener(this);
}

但 findViewById 不是此 Activity 的已知符号。是否有其他方法可以将可点击按钮合并到上述 fragment Activity 中？

运行项目，我得到这个错误。 (我不知道建议的更改是否有效，我的应用程序因以下错误而崩溃)这是一个 fragment Activity ，我试图在单击按钮时生成 toast 。

public class in_room_dining extends Fragment
{
Button btn_order;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState)
{
    // TODO Auto-generated method stub

    btn_order.setOnClickListener(new OnClickListener()
{
 public void onClick(View v)
{
Toast.makeText(getActivity(), "text", Toast.LENGTH_SHORT).show();
}
});
 return inflater.inflate(R.layout.activity_in_room_dining, container, false);
}
}

我得到的错误是:

11-29 10:57:42.820      938-938/com.appt.shreyabisht.staymax E/AndroidRuntime﹕ FATAL EXCEPTION:     main
Process: com.appt.shreyabisht.staymax, PID: 938
java.lang.NullPointerException
        at com.appt.shreyabisht.staymax.in_room_dining.onCreateView(in_room_dining.java:23)
        at android.support.v4.app.Fragment.performCreateView(Fragment.java:1504)

(in_room_dining.java:23) 是 btn_order.setOnClickListener(new OnClickListener()

Answer 1

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class laundry extends Fragment {
Button btn_service;
@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // TODO Auto-generated method stub 
final View rootView = inflater.inflate(R.layout.activity_laundry, container,
                false);

    btn_service = (Button) rootView.findViewById(R.id.btn_service);
    btn_service.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

         //your Code Goes Here    
        }
    });
    return rootView;
}