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我正在爲事件構建應用程序，其中一個功能是留言板。爲此，我構建了一個ListView並加載了消息。具有多個項目類型的ListAdapter拋出ClassCastException
我有兩種類型的消息：你發送的消息和另一個發送的消息。佈局略有不同，U使用其他XML文件。我試過我的代碼（下面），如果所有項目都是相同類型的（你的或其他），它就可以正常工作。但是當類型改變時，我得到ClassCastException。我知道這意味着什麼，以及它出錯的地方（商品持有者是不同的類別，它試圖使類別的對象不是），而不是如何解決它。
這是我的代碼，這是我的ChatAdapter的getView。 ChatAdapter是延伸BaseAdapter的類。
public View getView(final int position, View convertView, ViewGroup parent) {
View vi=convertView;
final Message m = messagelist.get(position);
OwnMessageHolder ownMessageHolder;
OtherMessageHolder otherMessageHolder;
if(isSelf(m.getPerson().getId())) {
if (vi == null) { //convertview==null
ownMessageHolder = new OwnMessageHolder();
vi = inflater.inflate(R.layout.listitem_chat_own, null);
vi.setOnClickListener(null);
vi.setOnLongClickListener(null);
vi.setLongClickable(false);
ownMessageHolder.name = (TextView) vi.findViewById(R.id.tv_chat_own_name);
ownMessageHolder.message = (TextView) vi.findViewById(R.id.tv_chat_own_message);
vi.setTag(ownMessageHolder);
}else{//convertview is not null
ownMessageHolder = (OwnMessageHolder)vi.getTag();
}
ownMessageHolder.name.setText(m.getPerson().getName());
ownMessageHolder.message.setText(m.getMessages()[0]);
vi.setFocusable(false);
vi.setClickable(true);
return vi;
}else {//other
if (vi == null) { //convertview==null
otherMessageHolder = new OtherMessageHolder();
vi = inflater.inflate(R.layout.listitem_chat_other, null);
vi.setOnClickListener(null);
vi.setOnLongClickListener(null);
vi.setLongClickable(false);
otherMessageHolder.name = (TextView) vi.findViewById(R.id.tv_chat_other_name);
otherMessageHolder.message = (TextView) vi.findViewById(R.id.tv_chat_other_message);
vi.setTag(otherMessageHolder);
}else{//convertview is not null
otherMessageHolder = (OtherMessageHolder)vi.getTag();
}
otherMessageHolder.name.setText(m.getPerson().getName());
otherMessageHolder.message.setText(m.getMessages()[0]);
vi.setFocusable(false);
vi.setClickable(true);
return vi;
}
}
public static class OwnMessageHolder {
public TextView name;
public TextView message;
}
public static class OtherMessageHolder {
public TextView name;
public TextView message;
}
和錯誤日誌：
04-06 23:25:54.720: E/AndroidRuntime(18176): FATAL EXCEPTION: main
04-06 23:25:54.720: E/AndroidRuntime(18176): java.lang.ClassCastException: com.hera.lustrumvirgiel.ChatAdapter$OtherMessageHolder cannot be cast to com.hera.lustrumvirgiel.ChatAdapter$OwnMessageHolder
04-06 23:25:54.720: E/AndroidRuntime(18176): at com.hera.lustrumvirgiel.ChatAdapter.getView(ChatAdapter.java:57)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.AbsListView.obtainView(AbsListView.java:2449)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.ListView.measureHeightOfChildren(ListView.java:1244)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.ListView.onMeasure(ListView.java:1155)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.View.measure(View.java:12815)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.RelativeLayout.measureChild(RelativeLayout.java:627)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:440)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.View.measure(View.java:12815)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.View.measure(View.java:12815)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1399)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.LinearLayout.measureVertical(LinearLayout.java:690)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.LinearLayout.onMeasure(LinearLayout.java:583)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.View.measure(View.java:12815)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
04-06 23:25:54.720: E/AndroidRuntime(18176): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2106)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.View.measure(View.java:12815)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1068)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2452)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.os.Handler.dispatchMessage(Handler.java:99)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.os.Looper.loop(Looper.java:137)
04-06 23:25:54.720: E/AndroidRuntime(18176): at android.app.ActivityThread.main(ActivityThread.java:4493)
04-06 23:25:54.720: E/AndroidRuntime(18176): at java.lang.reflect.Method.invokeNative(Native Method)
04-06 23:25:54.720: E/AndroidRuntime(18176): at java.lang.reflect.Method.invoke(Method.java:511)
04-06 23:25:54.720: E/AndroidRuntime(18176): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788)
04-06 23:25:54.720: E/AndroidRuntime(18176): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
04-06 23:25:54.720: E/AndroidRuntime(18176): at dalvik.system.NativeStart.main(Native Method)
任何人知道如何解決這個問題？錯誤日誌所指的是（57）這一行是：
ownMessageHolder =（OwnMessageHolder）vi.getTag（）;
在此先感謝！