我有一个ListView的ListFragment。我想要做的是 - 当创建ListFragment时，我想要自动选择（突出显示）它的列表视图中的第一项。为突出显示listview行，我使用自定义列表选择器。我尝试将列表的第一项设置为选定状态，因此列表选择器也可以突出显示它。但是我的代码没有任何效果。也许有人可以帮我解决这个任务？我做错了什么？
更新：这是我的ListFragment代码：
public class ObjectListFragment extends ListFragment {
private DatabaseHandler databaseHandler;
private ArrayList<FFObject> ffObjects = new ArrayList<>();
private FFObjectsAdapter ffObjectAdapter;
private ArrayList<FFObject> arrayList;
private FFObject ffObject;
private long objectId;
static interface ObjectListListener{
void itemClicked(long id);
}
private ObjectListListener listener;
public ObjectListFragment() {
// Required empty public constructor
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
this.listener = (ObjectListListener) context;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
refreshData();
return inflater.inflate(R.layout.fragment_object_list, null);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
@Override
public void onResume() {
super.onResume();
ListView listView = getListView();
listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
listView.setItemChecked(2,true);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
arrayList = this.ffObjects;
ffObject = arrayList.get(position);
long itemId = ffObject.getObjectID();
Log.d("ObjectListFragment","Clicked on item with id = "+itemId);
if (listener != null){
listener.itemClicked(itemId);
}
}
public long getObjectId() {
arrayList = this.ffObjects;
ffObject = arrayList.get(0);
objectId = ffObject.getObjectID();
return objectId;
}
private void refreshData() {
ffObjects.clear();
databaseHandler = new DatabaseHandler(this.getActivity().getApplicationContext());
ArrayList<FFObject> ffobjectsFromDB = databaseHandler.getObjectsList();
for (int i = 0; i < ffobjectsFromDB.size(); i++) {
String title = ffobjectsFromDB.get(i).getTitle();
String dateText = ffobjectsFromDB.get(i).getRecordDate();
long objectid = ffobjectsFromDB.get(i).getObjectID();
FFObject ffobject = new FFObject();
ffobject.setTitle(title);
ffobject.setRecordDate(dateText);
ffobject.setObjectID(objectid);
ffObjects.add(ffobject);
}
databaseHandler.close();
//setup adapter
ffObjectAdapter = new FFObjectsAdapter(this.getActivity(), R.layout.object_row, ffObjects);
setListAdapter(ffObjectAdapter);
ffObjectAdapter.notifyDataSetChanged();
}
public class FFObjectsAdapter extends ArrayAdapter<FFObject>{
Context context;
int layoutResource;
FFObject ffObject;
ArrayList<FFObject> ffObjectArrayList = new ArrayList<>();
public FFObjectsAdapter (Context con, int resource, ArrayList<FFObject> data){
super(con,resource,data);
context = con;
layoutResource = resource;
ffObjectArrayList = data;
notifyDataSetChanged();
}
@Override
public int getCount() {
return ffObjectArrayList.size();
}
@Override
public FFObject getItem(int position) {
return ffObjectArrayList.get(position);
}
@Override
public int getPosition(FFObject item) {
return super.getPosition(item);
}
@Override
public long getItemId(int position) {
return super.getItemId(position);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
ViewHolder holder = null;
if (row == null || row.getTag()==null){
LayoutInflater inflater = LayoutInflater.from(context);
row = inflater.inflate(layoutResource, null);
holder = new ViewHolder();
holder.ffTitle = (TextView) row.findViewById(R.id.objectName);
holder.ffDate = (TextView) row.findViewById(R.id.dateText);
row.setTag(holder);
} else {
holder = (ViewHolder) row.getTag();
}
holder.ffObject = getItem(position);
holder.ffTitle.setText(holder.ffObject.getTitle());
holder.ffDate.setText(holder.ffObject.getRecordDate());
holder.ffId = holder.ffObject.getObjectID();
final ViewHolder finalHolder = holder;
return row;
}
class ViewHolder{
FFObject ffObject;
TextView ffTitle;
long ffId;
TextView ffDate;
}
}
@Override
public void onDetach() {
super.onDetach();
this.listener= null;
}
}
我的fragment_object_list.xml代码：
<?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="match_parent" android:orientation="vertical">
<ListView
android:id="@id/android:list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:choiceMode="singleChoice"
android:listSelector="@drawable/list_selector">
</ListView>
<TextView
android:id="@id/android:empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="@string/no_objects_in_application" >
</TextView>
</LinearLayout>
我的object_row.xml代码
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="12dp">
<ImageView
android:id="@+id/thumbnail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:src="@android:drawable/ic_menu_agenda"
/>
<TextView
android:id="@+id/objectName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="4dp"
android:layout_toRightOf="@id/thumbnail"
android:text="Object title"
android:textSize="13sp"
android:textStyle="bold"
/>
<TextView
android:id="@+id/dateText"
android:text="date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/thumbnail"
android:layout_below="@id/objectName"
android:layout_marginLeft="4dp"
android:textSize="12dp"
android:textStyle="italic"
/>
</RelativeLayout>
我的list_selector.xml代码
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- normal state. -->
<item android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/list_selector_selected" />
<!-- pressed state. -->
<item android:state_pressed="true" android:drawable="@drawable/list_selector_selected" />
<!-- selected state. -->
<item android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/list_selector_selected" />
<item android:state_activated="true" android:drawable="@drawable/list_selector_selected" />
</selector>
我的list_selector_selected.xml代码
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<gradient
android:endColor="#f7ddb8"
android:startColor="#f5c98c"
android:angle="90">
</gradient>
</shape>
我不在列表中使用单选按钮或复选框。所以我不认为我的问题是重复的topic。我成功使用列表选择器在单击时更改列表行的背景颜色。我的问题是：在列表片段活动开始后，如何将列表的TOP（第一行）设置为选定状态？我想自动完成，而不是用户点击事件。在这里的示例代码中，我使用position = 2.我知道这不是第一行，但此刻并不重要。无论如何，代码根本不起作用。行选择仅在点击事件中正确。