Question

我正在尝试显示java课程列表，并在Android Studio的主java类中为按钮创建了一个列表视图，但是当我尝试运行并单击该按钮时，它会打开另一个窗口，但列表视图不会出现这样的情况。 t显示它位于Android Studio的预览窗格上。

这是我的java类代码：

package unitysoftwenteam.mymainuidesign;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.ArrayAdapter;
import java.util.ArrayList;
import java.util.List;

public class JAVA_ACTIVITY extends AppCompatActivity {

ListView listview;
List list = new ArrayList();
ArrayAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_java__activity);

    listview = (ListView)findViewById(R.id.jtutoriallist);

    list.add("About Java");
    list.add("Print Hello Java");
    list.add("Variables");
    list.add("Updating Variables");
    list.add("Displaying the Output");
    list.add("String Variables");
    list.add("String Concatenation");
    list.add("Variable Names");
    list.add("Data Types");
    list.add("Variable Arithmetic");
    list.add("Casting");
    list.add("Control Flow");
    list.add("If Statement");
    list.add("Variable Scope");
    list.add("Else Statement");
    list.add("Else-If");
    list.add("Boolean Expressions");
    list.add("Logical Operators");
    list.add("Nested If Statements");
    list.add("Switch Statement");

    adapter = new ArrayAdapter(JAVA_ACTIVITY.this, 
    android.R.layout.simple_list_item_1);
    listview.setAdapter(adapter);
}
}

这是我的XML代码：

<?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"
tools:context="unitysoftwenteam.mymainuidesign.JAVA_ACTIVITY">

  <ListView
    android:id="@+id/jtutoriallist"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true" />
</RelativeLayout>

Answer 1

实际上你做的每件事情都是正确的，但你只需要指定要用ini_set("log_errors", 0);调整的列表：

<VirtualHost *:80>
    ServerAdmin admin@myapp.dev
    ServerName myapp.dev
    ServerAlias www.myapp.dev
    DocumentRoot /home/vagrant/code/public
    ErrorLog /dev/null
    CustomLog /dev/null common
</VirtualHost>

Answer 2

试用此代码

ListView listview;
List list;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    list = new ArrayList();
    listview= (ListView) findViewById(R.id.jtutoriallist);

    lists = (ListView) findViewById(R.id.lists);
    list.add("About Java");
    list.add("Print Hello Java");
    list.add("Variables");
    list.add("Updating Variables");
    .
    .
    .

   ArrayAdapter adapter = new ArrayAdapter(MainActivity.this, android.R.layout.simple_list_item_1, list);
   lists.setAdapter(adapter);
  }

Answer 3

您错过了将数据发送到适配器。＆＃39;列表＆＃39;你创造了。适配器需要数据和视图来绑定和填充相同的内容。你已经指定了布局但是错过了数据。

只需将其更改为，

adapter = new ArrayAdapter(JAVA_ACTIVITY.this, 
    android.R.layout.simple_list_item_1,list);
    listview.setAdapter(adapter);

Listview没有显示？

3 个答案: