Fragment Transaktion weder funktioniert noch geben Fehler

Question

Ich bin neu in Android, und ich versuche, über Fragment Transaction zu lernen. Aber ich bekomme nicht die erforderliche Ausgabe oder irgendeinen Fehler über den Fehler. Bitte hilf mir.

MainActivity:

package com.example.runwaylabz.canvinew; 


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

public class MainActivity extends AppCompatActivity { 

public static FragmentManager fragmentmanager; 


@Override 
protected void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    fragmentmanager = getSupportFragmentManager(); 
    fragmentmanager.beginTransaction().add(R.id.main_layout,new Canvi_Select(),"add_canvi_select").commit(); 


} 

@Override 
protected void onDestroy() { 
    super.onDestroy(); 

} 
} 

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?> 
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:background="@color/cardview_light_background" 
    android:id="@+id/main_layout" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    tools:context="com.example.runwaylabz.canvinew.MainActivity" 
    android:orientation="horizontal"> 

</LinearLayout> 

CanviSelect:

package com.example.runwaylabz.canvinew; 


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 Canvi_Select extends Fragment implements View.OnClickListener { 


private Button button1,button2,button3; 

public Canvi_Select() { 
    // Required empty public constructor 
} 


@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    View v=inflater.inflate(R.layout.fragment_canvi__select, container, false); 
    button1= (Button) v.findViewById(R.id.button8nodes); 
    button2= (Button) v.findViewById(R.id.button4nodes); 
    button3= (Button) v.findViewById(R.id.buttonplug); 
    button1.setOnClickListener(this); 
    button2.setOnClickListener(this); 
    button3.setOnClickListener(this); 
    return v; 
} 

@Override 
public void onClick(View view) { 
    switch (view.getId()){ 
     case R.id.button8nodes: 
      MainActivity.dataconnection.setType(8); 
      break; 
     case R.id.button4nodes: 
      MainActivity.dataconnection.setType(4); 
      break; 
     case R.id.buttonplug: 
      MainActivity.dataconnection.setType(1); 
      break; 
    } 
    MainActivity.fragmentmanager.beginTransaction().replace(R.id.main_layout,new CanviSearch(),"add_canvi_search").addToBackStack("canvi_search_back").commit(); 
} 
} 

Answer 1

Versuchen Sie, Ihre activity_main.xml wie dies zu ändern:

<?xml version="1.0" encoding="utf-8"?> 
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:background="@color/cardview_light_background" 
    android:id="@+id/main_layout" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    tools:context="com.example.runwaylabz.canvinew.MainActivity" 
    android:orientation="horizontal"> 
    <FrameLayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:id="@+id/frag_container"/> 

</LinearLayout> 

Jetzt

getSupportFragmentManager().beginTransaction().add(R.id.frag_container,new Canvi_Select(),"add_canvi_select").commit();