ListView不显示

Question

我想获得一个listview来显示，但它不是。我已阅读了其他一些帖子，无法找到问题。

这是我设置适配器的代码片段。我已经检查过调试器，并且之后没有设置为空。

tournaments = (ArrayList) dataSnapshot.getValue(); 
       adapter = new ArrayAdapter(AdminControl.this, android.R.layout.simple_list_item_1, tournaments); 
       list.setAdapter(adapter); 

这里是XML内容的文件：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout 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" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context="com.example.kaushikshivakumar.vexteamqueuing.AdminControl" 
    tools:showIn="@layout/activity_admin_control" 
    android:background="#ffffff"> 


<ListView 
    android:layout_width="wrap_content" 
    android:layout_height="fill_parent" 
    android:id="@+id/listView" 
    android:layout_alignParentTop="true" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" 
    android:layout_marginBottom="30dp" /> 
</RelativeLayout> 

这里是XML活动文件 - activity_admin_control

<?xml version="1.0" encoding="utf-8"?> 
<android.support.design.widget.CoordinatorLayout 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" 
android:fitsSystemWindows="true" 
tools:context="com.example.kaushikshivakumar.vexteamqueuing.AdminControl" 
app:theme = "@style/NoActionBar"> 

<android.support.design.widget.AppBarLayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:theme="@style/NoActionBar"> 

    <android.support.v7.widget.Toolbar 
     android:id="@+id/toolbar" 
     android:layout_width="match_parent" 
     android:layout_height="?attr/actionBarSize" 
     android:background="?attr/colorPrimary" 
     app:popupTheme="@style/AppTheme.PopupOverlay" 
     /> 

</android.support.design.widget.AppBarLayout> 

<android.support.design.widget.FloatingActionButton 
    android:id="@+id/fab" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_gravity="bottom|end" 
    android:layout_margin="@dimen/fab_margin" 
    android:src="@android:drawable/ic_input_add" 
    android:onClick="createNewTournament" 
    android:clickable="true" /> 


</android.support.design.widget.CoordinatorLayout> 

我的整个活动类：

package com.example.kaushikshivakumar.vexteamqueuing; 

import android.app.ActionBar; 
import android.content.Intent; 
import android.provider.ContactsContract; 
import android.support.design.widget.FloatingActionButton; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.support.v7.widget.Toolbar; 
import android.view.View; 
import android.widget.ArrayAdapter; 
import android.widget.ListAdapter; 
import android.widget.ListView; 
import android.widget.TextView; 

import com.firebase.client.DataSnapshot; 
import com.firebase.client.Firebase; 


import java.lang.Object.*; 

import com.firebase.client.FirebaseError; 
import com.firebase.client.ValueEventListener; 
import com.firebase.client.authentication.*; 
//import com.firebase.ui.database.FirebaseListAdapter; 

import java.lang.reflect.Array; 
import java.util.ArrayList; 
import java.util.List; 

public class AdminControl extends AppCompatActivity { 
Firebase ref; 
FloatingActionButton fab; 
public static List <Tournament> tournaments; 
public static DataSnapshot currentSnap; 
ArrayAdapter adapter; 
ListView list; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_admin_control); 
    Toolbar b = (Toolbar) findViewById(R.id.toolbar); 
    b.setTitle("Tournaments"); 
    setSupportActionBar(b); 
    list = (ListView) findViewById(R.id.listView); 
    fab = (FloatingActionButton) findViewById(R.id.fab); 
    fab.setOnClickListener(new View.OnClickListener() { 
     public void onClick(View v) { 
      createNewTournament(v); 
     } 
    }); 
    ref = AdminLogin.firebase.child("users").child(AdminLogin.firebase.getAuth().getUid()); 
    ref.addValueEventListener(new ValueEventListener() { 
     @Override 
     public void onDataChange(DataSnapshot dataSnapshot) { 
      if (dataSnapshot.getValue() != null){ 
       tournaments = (ArrayList) dataSnapshot.getValue(); 
       adapter = new ArrayAdapter(AdminControl.this, android.R.layout.simple_list_item_1, tournaments); 
       list.setAdapter(adapter); 
      } 
      else{ 
       tournaments = new ArrayList<>(); 
       adapter = new ArrayAdapter(AdminControl.this, android.R.layout.simple_list_item_1, tournaments); 
       list.setAdapter(adapter); 
      } 

      currentSnap = dataSnapshot; 
     } 

     @Override 
     public void onCancelled(FirebaseError firebaseError) { 

     } 
    }); 
} 

public void createNewTournament(View v) { 
    if (tournaments == null){ 
     System.out.println(tournaments); 
    } 
    Intent newIntent = new Intent(this, TournamentCreator.class); 
    startActivity(newIntent); 
} 

}

Answer 1

您需要在activity_admin_control.xml中包含您的内容文件。现在没有指向内容文件。活动不知道它存在。