我正在实现来自 Tjerk Wolternik 的Slide ExpandableListAdapter，但是当我正在使用它的列表被调用时，我得到了一个 ClassCastException。我希望有人能帮我弄清楚为什么会这样。
我在自定义数组适配器上使用它，如下所示：
public class ResultsAdapter extends ArrayAdapter<String> {
private final LayoutInflater layoutInflater;
public ResultsAdapter(Context context, int textViewResourceId) {
super(context, textViewResourceId);
layoutInflater = LayoutInflater.from(context);
}
@Override
public View getView(int position, View convertView, ViewGroup parent){
if(convertView == null){
convertView = layoutInflater.inflate(R.layout.row, null); //must be overall layout
}
TextView venName = (TextView) convertView.findViewById(R.id.rowName);
TextView venAddress = (TextView) convertView.findViewById(R.id.rowAdd);
venName.setText(VenueList.getVenueName(position));
venAddress.setText(VenueList.getVenueAddress(position));
return convertView;
}
}
我正在使用的 ListView 是 ListFragment 的扩展，它就在这里：
public class ListFragmentClickable extends ListFragment{
private OnItemSelectedListener listener;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_results, container, false);
return view;
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
updateDetail(position); //see bottom
}
public interface OnItemSelectedListener {
public void onItemSelected(String name);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (activity instanceof OnItemSelectedListener) {
listener = (OnItemSelectedListener) activity;
} else {
throw new ClassCastException(activity.toString()
+ " must implement ListFragmentClickable.OnItemSelectedListener");
}
}
public void updateDetail(int position) {
String name = VenueList.getVenueName(position);
listener.onItemSelected(name);
}
}
logcat 指向库代码的这一部分（特别是final LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)target.getLayoutParams();）：
private void updateExpandable(View target, int position) {
final LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)target.getLayoutParams();
if(openItems.get(position)) {
target.setVisibility(View.VISIBLE);
params.bottomMargin = 0;
} else {
target.setVisibility(View.GONE);
params.bottomMargin = 0-viewHeights.get(position);
}
}
这是我的日志：
07-31 23:42:20.931: E/AndroidRuntime(3557): FATAL EXCEPTION: main
07-31 23:42:20.931: E/AndroidRuntime(3557): java.lang.ClassCastException: android.widget.RelativeLayout$LayoutParams
07-31 23:42:20.931: E/AndroidRuntime(3557): at com.tjerkw.slideexpandable.library.AbstractSlideExpandableListAdapter.updateExpandable(AbstractSlideExpandableListAdapter.java:222)
07-31 23:42:20.931: E/AndroidRuntime(3557): at com.tjerkw.slideexpandable.library.AbstractSlideExpandableListAdapter.enableFor(AbstractSlideExpandableListAdapter.java:159)
07-31 23:42:20.931: E/AndroidRuntime(3557): at com.tjerkw.slideexpandable.library.AbstractSlideExpandableListAdapter.enableFor(AbstractSlideExpandableListAdapter.java:142)
07-31 23:42:20.931: E/AndroidRuntime(3557): at com.tjerkw.slideexpandable.library.AbstractSlideExpandableListAdapter.getView(AbstractSlideExpandableListAdapter.java:64)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.AbsListView.obtainView(AbsListView.java:1449)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.ListView.onMeasure(ListView.java:1103)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3261)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3261)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3261)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3261)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:683)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.LinearLayout.onMeasure(LinearLayout.java:311)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3261)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.LinearLayout.measureVertical(LinearLayout.java:531)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3261)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.View.measure(View.java:8532)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewRoot.performTraversals(ViewRoot.java:915)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.view.ViewRoot.handleMessage(ViewRoot.java:1991)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.os.Handler.dispatchMessage(Handler.java:99)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.os.Looper.loop(Looper.java:150)
07-31 23:42:20.931: E/AndroidRuntime(3557): at android.app.ActivityThread.main(ActivityThread.java:4358)
07-31 23:42:20.931: E/AndroidRuntime(3557): at java.lang.reflect.Method.invokeNative(Native Method)
07-31 23:42:20.931: E/AndroidRuntime(3557): at java.lang.reflect.Method.invoke(Method.java:507)
07-31 23:42:20.931: E/AndroidRuntime(3557): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
07-31 23:42:20.931: E/AndroidRuntime(3557): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
07-31 23:42:20.931: E/AndroidRuntime(3557): at dalvik.system.NativeStart.main(Native Method)
谁能向我解释发生了什么？我在布局中使用了线性布局，所以我不确定投射问题是什么。我的布局完全遵循 github 链接中的内容。谢谢您的帮助。
编辑：这里也是 row.xml：
<?xml version="1.0" encoding="utf-8"?>
<TextView
android:id="@+id/rowName"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:textStyle="bold"
android:textSize="16dp"
android:focusable="false"
android:paddingLeft="5dp" />
<TextView
android:id="@+id/rowAdd"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_below="@id/rowName"
android:focusable="false"
android:paddingTop="2dp"
android:paddingLeft="5dp"/>
<TextView
android:id="@+id/rowFit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:paddingTop="5dp"
android:paddingRight="10dp"
android:focusable="false"
android:textStyle="bold"
android:textSize="18dp" />
<TextView
android:id="@+id/rowDist"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
android:paddingBottom="5dp"
android:paddingRight="10dp"
android:focusable="false"/>
<!-- below this is xml for slide expandablelistview -->
<Button
android:id="@+id/expandable_toggle_button"
android:text="More"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/text"
android:layout_alignParentRight="true"
android:layout_alignTop="@id/text"/>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:id="@+id/expandable"
android:background="#000000">
<!-- put whatever you want in the expandable view -->
<TextView
android:id="@+id/testtext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="5dp"
android:text="testtestest"
android:paddingRight="10dp"
android:focusable="false"
android:textStyle="bold"
android:textSize="18dp" />
</LinearLayout>
<!-- slide expandablelistview xml ends here -->