我刚开始使用Android ListView。但是，只有当setAdapter被类ListActivity扩展时，我的程序中的DisplayMovie函数才有效。当我使用ListActivity并删除Activity时，应用程序崩溃了。由于无法支持多个继承，我想知道是否有一种方法可以在我的程序中同时使用ListViewActivity和Activity类。
//public class DisplayMovies extends ListActivity {
public class DisplayMovies extends Activity {
/** Called when the activity is first created. */
public String flixURL="";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main3);
Bundle extras = getIntent().getExtras();
int myzip = extras.getInt("globalZip");
flixURL=("http://servermin.com:19818/cgi-bin/movielog.pl?zip=" + myzip);
displayAllMovieList();
}
public void displayAllMovieList()
{
SAXBuilder builder = new SAXBuilder();
URL url;
try
{
url = new URL(flixURL);
Document doc = null;
doc=builder.build(url);
Element root = doc.getRootElement();
List children = root.getChild("movies").getChildren("movie");
System.out.println("Tracker3");
int MovieNum=children.size(); //Count the number of Movies
String[] MovieName=new String[MovieNum]; //Initialize a String
String[] MovieCover=new String[MovieNum];
String[] ShowTime=new String[MovieNum];
String TheatereName = ((Element) doc.getRootElement().getChild("movies").getChildren("movie").get(0)).getAttributeValue( "theatre" );
String TweetText="";
for (int i = 0; i < children.size(); i++)
{
Element movieAtt = (Element)doc.getRootElement().getChild("movies").getChildren("movie").get(i);
MovieName[i]=movieAtt.getAttributeValue( "Title" );
MovieCover[i]=movieAtt.getAttributeValue( "cover" );
ShowTime[i]=movieAtt.getAttributeValue( "showtime" );
finalTime=movieAtt.getAttributeValue( "showtime" ).substring(0,8);
TweetText+=" I will see "+movieAtt.getAttributeValue("Title")+" at "+TheatereName+" at "+finalTime+"\n";
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, MovieName);
setListAdapter(adapter);
//TextView tv = new TextView(this);
//tv.setText(TweetText);
//setContentView(tv);
}
}
catch (MalformedURLException e1)
{
e1.printStackTrace();
System.out.println("ErrorThrowedIs: "+e1);
Toast.makeText(getBaseContext(), e1.toString(),5);
}
catch (JDOMException e2)
{
e2.printStackTrace();
System.out.println("ErrorThrowedIs: "+e2);
Toast.makeText(getBaseContext(), e2.toString(),5);
}
catch (IOException e3)
{
e3.printStackTrace();
System.out.println("ErrorThrowedIs: "+e3);
Toast.makeText(getBaseContext(), e3.toString(),5);
}
}
}
错误日志说：
11-21 02:18:19.609: W/dalvikvm(21193): threadid=1: thread exiting with uncaught exception (group=0x4001d7d0)
11-21 02:18:19.629: E/AndroidRuntime(21193): FATAL EXCEPTION: main
11-21 02:18:19.629: E/AndroidRuntime(21193): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.vj/com.vj.DisplayMovies}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.os.Handler.dispatchMessage(Handler.java:99)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.os.Looper.loop(Looper.java:123)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ActivityThread.main(ActivityThread.java:4627)
11-21 02:18:19.629: E/AndroidRuntime(21193): at java.lang.reflect.Method.invokeNative(Native Method)
11-21 02:18:19.629: E/AndroidRuntime(21193): at java.lang.reflect.Method.invoke(Method.java:521)
11-21 02:18:19.629: E/AndroidRuntime(21193): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
11-21 02:18:19.629: E/AndroidRuntime(21193): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
11-21 02:18:19.629: E/AndroidRuntime(21193): at dalvik.system.NativeStart.main(Native Method)
11-21 02:18:19.629: E/AndroidRuntime(21193): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ListActivity.onContentChanged(ListActivity.java:245)
11-21 02:18:19.629: E/AndroidRuntime(21193): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:203)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.Activity.setContentView(Activity.java:1647)
11-21 02:18:19.629: E/AndroidRuntime(21193): at com.vj.DisplayMovies.onCreate(DisplayMovies.java:30)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-21 02:18:19.629: E/AndroidRuntime(21193): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
11-21 02:18:19.629: E/AndroidRuntime(21193): ... 11 more
更新了XML：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ListView android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#00FF00"
android:layout_weight="1"
android:drawSelectorOnTop="false"/>
<TextView android:id="@android:id/empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FF0000"
android:text="No data"/>
</LinearLayout>
更新了该课程的代码：
public class DisplayMovies extends ListActivity {
//public class DisplayMovies extends Activity {
/** Called when the activity is first created. */
public String flixURL="";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main3);
Bundle extras = getIntent().getExtras();
int myzip = extras.getInt("globalZip");
flixURL=("http://myweb.com/cgi-bin/movielog.pl?zip=" + myzip);
displayAllMovieList();
}
public void displayAllMovieList()
{
SAXBuilder builder = new SAXBuilder();
URL url;
try
{
url = new URL(flixURL);
Document doc = null;
doc=builder.build(url);
Element root = doc.getRootElement();
List children = root.getChild("movies").getChildren("movie");
System.out.println("Tracker2");
System.out.println("Tracker3");
int MovieNum=children.size(); //Count the number of Movies
String[] MovieName=new String[MovieNum]; //Initialize a String
String[] MovieCover=new String[MovieNum];
String[] ShowTime=new String[MovieNum];
String TheatereName = ((Element) doc.getRootElement().getChild("movies").getChildren("movie").get(0)).getAttributeValue( "theatre" );
String TweetText="";
for (int i = 0; i < children.size(); i++)
{
Element movieAtt = (Element)doc.getRootElement().getChild("movies").getChildren("movie").get(i);
MovieName[i]=movieAtt.getAttributeValue( "Title" );
MovieCover[i]=movieAtt.getAttributeValue( "cover" );
ShowTime[i]=movieAtt.getAttributeValue( "showtime" );
finalTime=movieAtt.getAttributeValue( "showtime" ).substring(0,8); TweetText+=" I will see "+movieAtt.getAttributeValue("Title")+" at "+TheatereName+" at "+finalTime+"\n";
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, MovieName);
setListAdapter(adapter);
}
}
catch (MalformedURLException e1)
{
e1.printStackTrace();
System.out.println("ErrorThrowedIs: "+e1);
Toast.makeText(getBaseContext(), e1.toString(),5);
}
catch (JDOMException e2)
{
e2.printStackTrace();
System.out.println("ErrorThrowedIs: "+e2);
Toast.makeText(getBaseContext(), e2.toString(),5);
}
catch (IOException e3)
{
e3.printStackTrace();
System.out.println("ErrorThrowedIs: "+e3);
Toast.makeText(getBaseContext(), e3.toString(),5);
}
}
}
答案 0 :(得分：3)
首先，如果您的应用崩溃了，并且您在提问题，请确保您还包含日志中的堆栈跟踪。
关于您的问题，请确保您了解使用ListActivity的前提条件：您的布局中必须有一个列表视图，其中包含android:id="@android:id/list"（如docs中所述）。我非常肯定这是你的应用程序崩溃的原因。
无论如何你不需要多继承：ListActivity扩展Activity，扩展它们都没有意义，即使Java有多重继承。