Question

这是一个活动的java类，我试图做的是在点击一个按钮时生成一个toast但是我得到了上面的错误。我尝试添加一个封闭的括号，但它引发了同样的错误。

public class btntoast extends Fragment
{
Button btn_order;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) 
{
    // TODO Auto-generated method stub
    return inflater.inflate(R.layout.activity_in_room_dining, container, false);
    btn_order.setOnClickListener(new OnClickListener() 
    {
        public void onClick(View v) 
        {
            Toast.makeText(getActivity(), "text", Toast.LENGTH_SHORT).show();
        }
    }
 }
}

更新代码：

public class in_room_dining extends Fragment
{
Button btn_order;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState)

{ // TODO自动生成的方法存根

    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);
}
}

抛出的错误是：

11-29 09:38:22.098    1138-1138/com.appt.shreyabisht.staymax W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1ab9ba8)
11-29 09:38:22.138    1138-1138/com.appt.shreyabisht.staymax E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.appt.shreyabisht.staymax, PID: 1138
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)

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

Answer 1

你错过了＃34;）＆＃34; setOnClickListener

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);

由于return语句，

也是无法访问的代码把它放在onCreateView;

的末尾

Answer 2

试试这个

btn_order.setOnClickListener(new OnClickListener() 
    {
        public void onClick(View v) 
        {
            Toast.makeText(getActivity(), "text", Toast.LENGTH_SHORT).show();
        }
    }
 });

Answer 3

在定义OnClickListener之后添加);就像这样简单：

    btn_order.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(getActivity(), "text", Toast.LENGTH_SHORT).show();
        }
    });

Answer 4

尝试这样：

   public class btntoast extends Fragment
    {
       Button btn_order;
       @Override
       public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) 
      {
          View v = inflater.inflate(R.layout.hello_world, container, false);
          btn_order =(Button) v.findViewById(R.id.text);
          btn_order.setOnClickListener(new OnClickListener() 
          {
             public void onClick(View v) 
             {
                Toast.makeText(getActivity(), "text", Toast.LENGTH_SHORT).show();
             }
          });

          return v;
      }
   }

错误：'）'预计

4 个答案: