Android:如何将ListView放入XML？

Question

我想创建一个简单的应用程序,显示联系人列表(姓名,姓氏).我的代码:

package lista.android;

import java.util.*;

import android.app.ListActivity;
import android.os.Bundle;
import android.widget.*;

class Contact{
    String nume;
    String prenume;

    Contact(String nume, String prenume){
        this.nume=nume;
        this.prenume=prenume;
    }

    public String toString(){
        return prenume +" "+ nume;
    }
}

public class Lista1Activity extends ListActivity {
    /** Called when the activity is first created. */
    ArrayList <Contact> lista;
    ArrayAdapter <Contact> adaptor;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        setListAdapter(adaptor);

        lista=new ArrayList<Contact>();
        adaptor=new ArrayAdapter<Contact>(this, R.id.element, lista);

        adaugaContact("Florian", "Iancu");
        adaugaContact("Ioana", "Constantina");

    }

    public void adaugaContact(String nume, String prenume){
        lista.add(new Contact(nume, prenume));
        adaptor.notifyDataSetChanged();
    }
}

在XML中,我有一个LinearLayout和TextView那个是列表元素.当我运行它时,模拟器说"Sorry, the application [...] has stopped unexpectedly. Please try again."LogCat告诉我我ListView的id必须是android.R.id.lista.如果我ListView在XML文件中创建一个随机字段并给它"lista"id,它仍然不起作用.如何从XML调用ListView以匹配我的Java代码中的内容？换句话说,我知道我错了,但我在哪里以及如何解决它？

Answer 1

在LinearLayout中,您必须指定ListView组件.

这是你的main.xml应该是这样的:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <ListView
        android:id="@+id/sampleListView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="5dp"
        android:background="@android:color/transparent"
        android:cacheColorHint="@android:color/transparent"
        android:divider="#CCCCCC"
        android:dividerHeight="1dp"
        android:paddingLeft="2dp" >
    </ListView>

</LinearLayout>

然后为listview创建一个布局:list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:padding="10dp"    android:textSize="16sp" >
</TextView>

像这样更改您的活动类:

public class Lista1Activity extends ListActivity {
    ArrayList<Contact> lista;
    ArrayAdapter<Contact> adaptor;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    lista = new ArrayList<Contact>();
    adaugaContact("Florian", "Iancu");
    adaugaContact("Ioana", "Constantina");

     adaptor = new ArrayAdapter<String>(this, R.layout.list_item, lista);

    setListAdapter(adaptor);
    }

    public void adaugaContact(String nume, String prenume) {
    lista.add(new Contact(nume, prenume));
    adaptor.notifyDataSetChanged();
    }
}