片段不會顯示onButtonClick

Question

片段默認顯示，但我希望它被隱藏/隱藏，直到我點擊這個按鈕。我遇到的問題是，當我點擊這個按鈕時，片段不會顯示出來。當涉及到碎片時，我是一個完整的初學者。

我在我的主要活動代碼：

package com.example.julian.tutorial_fragment; 

import android.support.v4.app.FragmentManager; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 

public class MainActivity extends AppCompatActivity implements TopSectionFragment.TopSectionListener{ 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     View frag = findViewById(R.id.fragment3); 
     frag.setVisibility(View.GONE); 
    } 

    //This gets called by the TopFragment when the user clicks the button 
    @Override 
    public void createMeme(String top, String bottom) { 
     BottomPictureFragment bottomFragment = (BottomPictureFragment)getSupportFragmentManager().findFragmentById(R.id.fragment2); 
     bottomFragment.setMemeText(top, bottom); 
    } 
//this is the onButtonClick 
    public void sample(View view) { 
     android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager(); 
     android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
     Fragment_Search hello = new Fragment_Search(); 
     fragmentTransaction.add(R.id.fragment3, hello, "HELLO"); 
     fragmentTransaction.commit(); 
    } 
} 

我在Fragment_Search代碼：

package com.example.julian.tutorial_fragment; 

import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.support.v4.app.Fragment; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

/** 
* Created by Julian on 8/17/2017. 
*/ 

public class Fragment_Search extends Fragment { 

    public interface Fragment_SearchInterface { 


    } 
    @Nullable 
    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 
     View view = inflater.inflate(R.layout.sample_layout, container, false); 

     return view; 
    } 
} 

我activity_main.xml中

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    tools:context="com.example.julian.tutorial_fragment.MainActivity"> 

    <RelativeLayout 
     android:layout_width="377dp" 
     android:layout_height="498dp" 
     tools:layout_editor_absoluteY="8dp" 
     tools:layout_editor_absoluteX="8dp"> 

     <fragment 
      android:id="@+id/fragment2" 
      android:name="com.example.julian.tutorial_fragment.BottomPictureFragment" 
      android:layout_width="250dp" 
      android:layout_height="250dp" 
      tools:layout="@layout/bottom_picture_fragment" 
      tools:layout_editor_absoluteX="67dp" 
      tools:layout_editor_absoluteY="223dp" 
      android:layout_marginBottom="30dp" 
      android:layout_alignParentBottom="true" 
      android:layout_centerHorizontal="true" /> 

     <fragment 
      android:id="@+id/fragment" 
      android:name="com.example.julian.tutorial_fragment.TopSectionFragment" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      tools:layout="@layout/top_section_fragment" 
      tools:layout_editor_absoluteX="42dp" 
      tools:layout_editor_absoluteY="16dp" 
      android:layout_alignParentTop="true" 
      android:layout_centerHorizontal="true" /> 

     <Button 
      android:id="@+id/button2" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_above="@+id/fragment2" 
      android:layout_alignStart="@+id/fragment" 
      android:text="Button" 
      android:onClick="sample"/> 

     <fragment 
      android:id="@+id/fragment3" 
      android:name="com.example.julian.tutorial_fragment.Fragment_Search" 
      android:layout_width="300dp" 
      android:layout_height="300dp" 
      android:layout_below="@+id/button2" 
      android:layout_marginTop="92dp" 
      android:layout_toStartOf="@+id/button2" /> 
    </RelativeLayout> 

</android.support.constraint.ConstraintLayout> 

Answer 1

改變你的樣品的功能和添加此

FragmentManager fragmentManager = getSupportFragmentManager(); 

    fragmentManager.beginTransaction() 
      .replace(R.id.your_layout, new Fragment_Search()) 
      .addToBackStack(null) 
      .commit();