片段中的按钮在android中不起作用

Posted 2023-04-15

【中文标题】片段中的按钮在android中不起作用

【英文标题】：Button in Fragment are not working in android

【发布时间】：2014-10-25 18:02:59

【问题描述】：

我已经阅读了很多帖子和问题和答案，但我无法解决我的问题。它不工作。

我有一个带有来自 android Studio 的 Mainmenu-Activity 的应用程序。现在我有一些片段被设置到容器中（通过替换）。

现在我在 Fragment 中添加了一个按钮，并希望它能够进行一些计算。但这是问题所在。这个按钮没有做任何事情。

这是我的代码：

package eu.terratex.terratextoolbox;

import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RatingBar;
import android.view.View.OnClickListener;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

/**
 * A simple @link Fragment subclass.
 * Activities that contain this fragment must implement the
 * @link Knastrechner.OnFragmentInteractionListener interface
 * to handle interaction events.
 * Use the @link Knastrechner#newInstance factory method to
 * create an instance of this fragment.
 *
 */
public class Knastrechner extends Fragment  

    private OnFragmentInteractionListener mListener;
    private Button btnClick;

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @return A new instance of fragment Knastrechner.
     */
    // TODO: Rename and change types and number of parameters
    public static Knastrechner newInstance() 
        Knastrechner fragment = new Knastrechner();
        Bundle args = new Bundle();
        return fragment;
    
    public Knastrechner() 
        // Required empty public constructor
    

    @Override
    public void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
    

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) 

        super.onCreateView(inflater, container, savedInstanceState);
        // Inflate the layout for this fragment
        View view = null;
        view = inflater.inflate(R.layout.fragment_knastrechner, container, false);
        Button mButton = (Button) view.findViewById(R.id.berechnenButton);

        mButton.setOnClickListener(new OnClickListener()

            @Override
            public void onClick(View view) 
                System.out.println("abc");
            
        );

        return inflater.inflate(R.layout.fragment_knastrechner, container, false);
    

    @Override
    public void onAttach(Activity activity) 
        super.onAttach(activity);
        try 
            mListener = (OnFragmentInteractionListener) activity;
         catch (ClassCastException e) 
            throw new ClassCastException(activity.toString()
                    + " must implement OnFragmentInteractionListener");
        
    

    @Override
    public void onDetach() 
        super.onDetach();
        mListener = null;
    

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener 
        // TODO: Update argument type and name
        public void onFragmentInteraction(Uri uri);
    

我在这里添加了onclick：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) 

    super.onCreateView(inflater, container, savedInstanceState);
    // Inflate the layout for this fragment
    View view = null;
    view = inflater.inflate(R.layout.fragment_knastrechner, container, false);
    Button mButton = (Button) view.findViewById(R.id.berechnenButton);


    mButton.setOnClickListener(new OnClickListener()

        @Override
        public void onClick(View view) 
            System.out.println("abc");
        
    );

    return inflater.inflate(R.layout.fragment_knastrechner, container, false);

谁能帮帮我？

【参考方案1】：

你应该使用return view; 而不是return inflater.inflate(R.layout.fragment_knastrechner, container, false);，否则你只是放弃了你之前在代码中所做的事情。

【讨论】：

哦，谢谢，3 小时搜索答案的简单解决方案：P

【参考方案2】：

改成

  return inflater.inflate(R.layout.fragment_knastrechner, container, false);

到

  return view;

因为您已经在 view 对象中扩充了布局。

【参考方案3】：

如果没有写入返回视图，则返回视图后的片段 evrey 为 null，则编写的所有代码都将不起作用

enter code h super.onCreateView(inflater, container, savedInstanceState);
// Inflate the layout for this fragment
View view = null;
view = inflater.inflate(R.layout.fragment_knastrechner, container, false);
Button mButton = (Button) view.findViewById(R.id.berechnenButton);


mButton.setOnClickListener(new OnClickListener()

    @Override
    public void onClick(View view) 
        System.out.println("abc");
    
);

return view;

在