Android Listview

<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:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/listView1"
        android:choiceMode="singleChoice"
        android:layout_width="match_parent"
        android:layout_height="318dp"
        android:layout_weight="0.73"
        android:entries="@array/spinner" >
    </ListView>

    <EditText
        android:id="@+id/editText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textMultiLine" >

        <requestFocus />
    </EditText>

</LinearLayout>

package com.example.listview;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {
ListView mListView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        showListview();
    }

    private void showListview() 
    {
    mListView=(ListView) findViewById(R.id.listView1);
    String[] COUNTRIES = new String[] { "Angola ", "Afghanis", "A,lbania", ",lgeria", ",ndorra", ",nguilla", "Ant,igua ", "Argen,tin", "Armenia,", "Ascens,o", "Australi", "Austria" ,"Azerbaij" ,"Bahamas", "B,ahrain", ",anglade", ",arbados", "Bel,arus", "Belgi,um", "Beli,e ", "Beni, ", "Bermuda ,", "Bolivia" , "Botswana" ,"Brazil " ,"Brunei ", "B,ulgaria", "Bur,kina-", "Burma, ", "Burundi", "Cameroon", "Canada " ,"Cayman I" ,"Central ", "C,had ", "Chile, ", "China ", "Colombia" ,"Congo ", ",Cook Is.", "C,osta Ri", "Cu,ba ", "Cyprus, ", "Czech , ", "Denmark" , "Djibouti" ,"Dominica" ,"Ecuador" , "E,gypt ", "EI S,alva", "Est,nia" , "Ethiop,ia", "Fiji ", "Finland" , "France " ,"French G", "G,abon ", "G,mbia ", "Geor,gia", "Germ,any" , "Gha,a ", "Gibralt,a", "Greece ", "Grenada", "Guam ", "Gu,atemal", "G,inea ", "G,yana ", "Hai,ti ", "Hondur,as", "Hongkong,", "Hungary", "Iceland", "India " ,"Indonesi", "I,ran ", "Iraq ", "Ireland", "Israel ", "Italy ", "I,vory Co", ",amaica" , ",apan ", "Jor,dan ", "Kampu,che", "Kazak,sta", "Kenya, ", "Korea, ", "Kuwait ", "Kyrgyzst", "Laos ", "La,tvia ", "L,banon" , "Les,otho" , "Liber,ia" , "Libya ,", "Liechten", "Lithuani" };    
    //ArrayAdapter<String> arrayAdapter=new  ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, COUNTRIES);
    ArrayAdapter<String> arrayAdapter=new  ArrayAdapter<String>(this, android.R.layout.select_dialog_singlechoice, COUNTRIES);
    mListView.setAdapter(arrayAdapter);
    
    
    }

}

 /**
 * @Title listviewDirect.java
 * @package     com.example.listview
 * @since  
 * @version     1.0.0 
 * @author      Vic Lee
 * @date        Aug 24, 2016-11:15:35 AM
 */
package com.example.listview;

import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class listviewDirectActivity extends ListActivity {
ListView mListView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);
        showlistviewDirect();
      
    }
    
    private void showlistviewDirect()
    {
        //mListView=getListView();
        String[] COUNTRIES = new String[] { "Angola ", "Afghanis", "A,lbania", ",lgeria", ",ndorra", ",nguilla", "Ant,igua ", "Argen,tin", "Armenia,", "Ascens,o", "Australi", "Austria" ,"Azerbaij" ,"Bahamas", "B,ahrain", ",anglade", ",arbados", "Bel,arus", "Belgi,um", "Beli,e ", "Beni, ", "Bermuda ,", "Bolivia" , "Botswana" ,"Brazil " ,"Brunei ", "B,ulgaria", "Bur,kina-", "Burma, ", "Burundi", "Cameroon", "Canada " ,"Cayman I" ,"Central ", "C,had ", "Chile, ", "China ", "Colombia" ,"Congo ", ",Cook Is.", "C,osta Ri", "Cu,ba ", "Cyprus, ", "Czech , ", "Denmark" , "Djibouti" ,"Dominica" ,"Ecuador" , "E,gypt ", "EI S,alva", "Est,nia" , "Ethiop,ia", "Fiji ", "Finland" , "France " ,"French G", "G,abon ", "G,mbia ", "Geor,gia", "Germ,any" , "Gha,a ", "Gibralt,a", "Greece ", "Grenada", "Guam ", "Gu,atemal", "G,inea ", "G,yana ", "Hai,ti ", "Hondur,as", "Hongkong,", "Hungary", "Iceland", "India " ,"Indonesi", "I,ran ", "Iraq ", "Ireland", "Israel ", "Italy ", "I,vory Co", ",amaica" , ",apan ", "Jor,dan ", "Kampu,che", "Kazak,sta", "Kenya, ", "Korea, ", "Kuwait ", "Kyrgyzst", "Laos ", "La,tvia ", "L,banon" , "Les,otho" , "Liber,ia" , "Libya ,", "Liechten", "Lithuani" };    
        ArrayAdapter<String> arrayAdapter=new  ArrayAdapter<String>(this, android.R.layout.select_dialog_singlechoice, COUNTRIES);
        setListAdapter(arrayAdapter);
    }

    
}

08-24 11:48:52.402: E/AndroidRuntime(15786): java.lang.RuntimeException: Unable to start activity ComponentInfo

{com.example.listview/com.example.listview.listviewDirectActivity}: java.lang.NullPointerException


解决办法：
因为listview 自动已经生成了id ,所以引用已经生成的id即可 在xml 页面。android:id="@android:id/list"

<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:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="186dp"
        android:layout_weight="0.87" >
    </ListView>

    <EditText
        android:id="@+id/editText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textMultiLine" >

        <requestFocus />
    </EditText>

</LinearLayout>

package com.example.listviw1;

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.app.Activity;
import android.app.ListActivity;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.ArrayAdapter;
import android.widget.EditText;

public class MainActivity extends ListActivity {
EditText mEditText;
ArrayAdapter<String> arrayAdapter;
List<String> mlistStrings;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        showListview1();
    }
private void showListview1() 
{
    mlistStrings=new  ArrayList<String>();
    arrayAdapter=new  ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mlistStrings);
    mEditText=(EditText) findViewById(R.id.editText1);
    mEditText.setOnKeyListener(new  OnKeyListener() {
        
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (keyCode==KeyEvent.KEYCODE_ENTER&& event.getAction()==KeyEvent.ACTION_UP)
            {
             mlistStrings.add(mEditText.getText().toString());
             
             setListAdapter(arrayAdapter);
             
             mEditText.setText(null);
            }
            
            return false;
            
        }
    });
}
}