我正在尝试做一些类似无尽的适配器但无法完成的事情,因此我的应用程序崩溃了。我试图做的是,最初我想在列表视图中加载 10 个项目并在列表视图的末尾添加脚注视图。如果用户单击脚注视图,则在列表视图中加载了 10 个以上的项目。
但是当我开始该活动时,只会出现页脚视图,几秒钟后应用程序崩溃。我在下面发布了相关代码:
int questionsPerPage = 10;
boolean loadingMore = false;
ArrayList<DataHolder> myquestionsResults;
QuestionListViewAdapter adapter;
//in onCreate
lv = (ListView) findViewById(R.id.lv_questions);
// add the footer before adding the adapter, else the footer will not
// load!
View footerView = ((LayoutInflater) this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(
R.layout.listfooter, null, false);
footerView.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
Thread thread = new Thread(null, loadMoreListItems);
thread.start();
}
});
lv.addFooterView(footerView);
myquestionsResults = new ArrayList<DataHolder>();
adapter = new QuestionListViewAdapter(this, myquestionsResults);
lv.setAdapter(adapter);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> a, View v, int position,
long id) {
Object o = lv.getItemAtPosition(position);
DataHolder fullObject = (DataHolder) o;
Intent intent = new Intent(getApplicationContext(),
ViewMyQuestion.class);
intent.putExtra("id", fullObject.getId());
startActivity(intent);
}
});
// Load the first 10 items
Thread thread = new Thread(null, loadMoreListItems);
thread.start();
}// End of onCreate
private ArrayList<DataHolder> GetMyQuestionsResult() {
ArrayList<DataHolder> myquestionInfo = new ArrayList<DataHolder>();
HashMap<String, String> hm = new HashMap<String, String>();
db = new DatabaseHandler(getApplicationContext());
db.getReadableDatabase();
hm = db.getUserDetails();
db.close();
String un = hm.get("username");
uf = new UserFunctions();
JSONArray json = uf.getQuestionsByUsername(un);
int x = json.length();
try {
if (x > 0) {
for (int i = 0; i < x; i++) {
ja = json.getJSONArray(i);
id = ja.getString(0);
userName = ja.getString(1);
question = ja.getString(2);
tag1 = ja.getString(3);
tag2 = ja.getString(4);
tag3 = ja.getString(5);
posted_on = ja.getString(6);
DataHolder qih = new DataHolder();
qih.setId(id);
qih.setUserName(userName);
qih.setQuestion(question);
qih.setTag1(tag1);
qih.setTag2(tag2);
qih.setTag3(tag3);
qih.setQuestionPostedOn(posted_on);
myquestionInfo.add(qih);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return myquestionInfo;
}
// Runnable to load the items
private Runnable loadMoreListItems = new Runnable() {
public void run() {
// Set flag so we cant load new items 2 at the same time
loadingMore = true;
// Reset the array that holds the new items
// Get 10 new listitems
for (int i = 0; i < questionsPerPage; i++) {
// Fill the item with some bogus information
myquestionsResults.add(GetMyQuestionsResult().get(i));
}
// Done! now continue on the UI thread
runOnUiThread(returnRes);
}
};
// Since we cant update our UI from a thread this Runnable takes care of
// that!
private Runnable returnRes = new Runnable() {
@SuppressWarnings("unchecked")
public void run() {
// Tell to the adapter that changes have been made, this will cause
// the list to refresh
((BaseAdapter) lv.getAdapter()).notifyDataSetChanged();
// Done loading more.
loadingMore = false;
}
};
以下是我的 logcat 消息:
08-27 06:00:03.799: E/AndroidRuntime(280): FATAL EXCEPTION: main
08-27 06:00:03.799: E/AndroidRuntime(280): java.lang.ClassCastException: android.widget.HeaderViewListAdapter
08-27 06:00:03.799: E/AndroidRuntime(280): at com.vervecoders.cuqu.MyQuestions$3.run(MyQuestions.java:275)
08-27 06:00:03.799: E/AndroidRuntime(280): at android.os.Handler.handleCallback(Handler.java:587)
08-27 06:00:03.799: E/AndroidRuntime(280): at android.os.Handler.dispatchMessage(Handler.java:92)
08-27 06:00:03.799: E/AndroidRuntime(280): at android.os.Looper.loop(Looper.java:123)
08-27 06:00:03.799: E/AndroidRuntime(280): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-27 06:00:03.799: E/AndroidRuntime(280): at java.lang.reflect.Method.invokeNative(Native Method)
08-27 06:00:03.799: E/AndroidRuntime(280): at java.lang.reflect.Method.invoke(Method.java:521)
08-27 06:00:03.799: E/AndroidRuntime(280): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-27 06:00:03.799: E/AndroidRuntime(280): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-27 06:00:03.799: E/AndroidRuntime(280): at dalvik.system.NativeStart.main(Native Method)
更新代码后它再次崩溃。以下是新的 logcat 消息:
08-27 07:38:47.751: I/dalvikvm(349): "main" prio=5 tid=1 RUNNABLE
08-27 07:38:47.751: I/dalvikvm(349): | group="main" sCount=0 dsCount=0 s=N obj=0x4001d8e0 self=0xccb0
08-27 07:38:47.751: I/dalvikvm(349): | sysTid=349 nice=0 sched=0/0 cgrp=default handle=-1345026008
08-27 07:38:47.751: I/dalvikvm(349): | schedstat=( 33038897911 15262681460 1352 )
08-27 07:38:47.751: I/dalvikvm(349): at java.util.ArrayList.add(ArrayList.java:~123)
08-27 07:38:47.765: I/dalvikvm(349): at com.vervecoders.cuqu.MyQuestions$3.run(MyQuestions.java:267)
08-27 07:38:47.765: I/dalvikvm(349): at android.os.Handler.handleCallback(Handler.java:587)
08-27 07:38:47.771: I/dalvikvm(349): at android.os.Handler.dispatchMessage(Handler.java:92)
08-27 07:38:47.771: I/dalvikvm(349): at android.os.Looper.loop(Looper.java:123)
08-27 07:38:47.771: I/dalvikvm(349): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-27 07:38:47.785: I/dalvikvm(349): at java.lang.reflect.Method.invokeNative(Native Method)
08-27 07:38:47.785: I/dalvikvm(349): at java.lang.reflect.Method.invoke(Method.java:521)
08-27 07:38:47.785: I/dalvikvm(349): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-27 07:38:47.785: I/dalvikvm(349): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-27 07:38:47.785: I/dalvikvm(349): at dalvik.system.NativeStart.main(Native Method)
08-27 07:38:47.811: D/AndroidRuntime(349): Shutting down VM
08-27 07:38:47.811: W/dalvikvm(349): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
08-27 07:38:47.845: E/AndroidRuntime(349): FATAL EXCEPTION: main
08-27 07:38:47.845: E/AndroidRuntime(349): java.lang.OutOfMemoryError
08-27 07:38:47.845: E/AndroidRuntime(349): at java.util.ArrayList.add(ArrayList.java:123)
08-27 07:38:47.845: E/AndroidRuntime(349): at com.vervecoders.cuqu.MyQuestions$3.run(MyQuestions.java:267)
08-27 07:38:47.845: E/AndroidRuntime(349): at android.os.Handler.handleCallback(Handler.java:587)
08-27 07:38:47.845: E/AndroidRuntime(349): at android.os.Handler.dispatchMessage(Handler.java:92)
08-27 07:38:47.845: E/AndroidRuntime(349): at android.os.Looper.loop(Looper.java:123)
08-27 07:38:47.845: E/AndroidRuntime(349): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-27 07:38:47.845: E/AndroidRuntime(349): at java.lang.reflect.Method.invokeNative(Native Method)
08-27 07:38:47.845: E/AndroidRuntime(349): at java.lang.reflect.Method.invoke(Method.java:521)
08-27 07:38:47.845: E/AndroidRuntime(349): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-27 07:38:47.845: E/AndroidRuntime(349): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-27 07:38:47.845: E/AndroidRuntime(349): at dalvik.system.NativeStart.main(Native Method)