我有一个奇怪的问题，我无法弄清楚问题是什么。我有以下简单的布局：
<?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/measuredata_list_row_parent"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginEnd="20dp"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:divider="@null"
android:dividerHeight="5dp"
android:listSelector="@android:color/transparent"
android:textColor="@color/textcolorprimary" />
</LinearLayout>
我使用的适配器如下：
public class MeasureDataListAdapter extends ArrayAdapter<MeasureDataListEntry> {
public MeasureDataListAdapter(Context context, List<MeasureDataListEntry> entries) {
super(context, R.layout.activity_measuredata_list_fragment_row, entries);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final MeasureDataListEntry entry = this.getItem(position);
ViewHolder viewHolder = null;
LayoutInflater inflater = null;
if(convertView == null) {
inflater = LayoutInflater.from(this.getContext());
convertView = inflater.inflate(R.layout.activity_measuredata_list_fragment_row, parent, false);
viewHolder = new ViewHolder();
viewHolder.textViewTime = (TextView) convertView.findViewById(R.id.measuredata_list_row_textview_time);
viewHolder.textViewValue = (TextView) convertView.findViewById(R.id.measuredata_list_row_textview_value);
viewHolder.textViewMood = (TextView) convertView.findViewById(R.id.measuredata_list_row_textview_mood);
viewHolder.layoutMealTime = (LinearLayout) convertView.findViewById(R.id.measuredata_list_row_layout_mealtime);
viewHolder.textViewMealTime = (TextView) convertView.findViewById(R.id.measuredata_list_row_textview_mealtime);
viewHolder.imageButtonMeal = (ImageButton) convertView.findViewById(R.id.measuredata_list_row_imagebutton_meal);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.textViewTime.setText(Helper.getDateTimePattern(this.getContext(), entry.getTime()));
viewHolder.textViewValue.setText(entry.getValue() + " " + Helper.getUnitForShortcut(this.getContext(), entry.getUnit()));
viewHolder.textViewMood.setText(Helper.getMood(this.getContext(), entry.getMood()));
String mealTime = Helper.getMealTimeForShortcut(this.getContext(), entry.getMealTime());
if(mealTime != null && !mealTime.trim().isEmpty()) {
viewHolder.layoutMealTime.setVisibility(LinearLayout.VISIBLE);
viewHolder.textViewMealTime.setText(mealTime);
}
File imageFile = entry.getImageFile();
if(imageFile != null) {
viewHolder.imageButtonMeal.setVisibility(ImageButton.VISIBLE);
}
return convertView;
}
private static class ViewHolder {
private TextView textViewTime = null;
private TextView textViewValue = null;
private TextView textViewMood = null;
private LinearLayout layoutMealTime = null;
private TextView textViewMealTime = null;
private ImageButton imageButtonMeal = null;
}
}
这是List的Fragment：
public class MeasureDataListFragment extends DiagramBaseFragment implements OnDateSetListener, MeasureDataGetCallback {
private MeasureDataListAdapter measureDataListAdapter = null;
private ListView listRowParent = null;
private List<MeasureDataListEntry> measureDataListEntries = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setRetainInstance(true);
this.setHasOptionsMenu(true);
this.sessionLoginPreferences = new SessionLoginPreferences(this.getActivity());
this.sessionLoginSingleton = SessionLoginSingleton.getInstance(this.getActivity());
this.sessionProfilePreferences = new SessionProfilePreferences(this.getActivity());
this.sessionMeasureDataPreferences = new SessionMeasureDataPreferences(this.getActivity());
this.sessionMeasureDataListSingleton = SessionMeasureDataListSingleton.getInstance();
this.sessionMeasureDataListFavouriteSingleton = SessionMeasureDataListFavouriteSingleton.getInstance();
if(this.sessionMeasureDataListSingleton.getMeasureDataList() == null) {
this.sessionMeasureDataListSingleton.setMeasureDataList(new MeasureDataList());
}
if(this.sessionMeasureDataListFavouriteSingleton.getMeasureDataList() == null) {
this.sessionMeasureDataListFavouriteSingleton.setMeasureDataList(new MeasureDataList());
}
this.measureDataListEntries = new ArrayList<MeasureDataListEntry>();
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.activity_measuredata_list_fragment, container, false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
this.measureDataListAdapter = new MeasureDataListAdapter(this.getActivity(), this.measureDataListEntries);
this.listRowParent = (ListView) view.findViewById(R.id.measuredata_list_row_parent);
this.listRowParent.setAdapter(this.measureDataListAdapter);
}
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if((this.sessionMeasureDataListFavouriteSingleton != null || this.sessionMeasureDataListSingleton != null)) {
this.fragmentBecameVisible();
}
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.diagram_activity_actions, menu);
super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
this.getActivity().finish();
return true;
case R.id.action_search:
this.showDatePicker(this.getResources().getString(R.string.text_from));
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
monthOfYear = (monthOfYear + 1);
if(view == null && year == 0 && monthOfYear == 0 && dayOfMonth == 0) {
this.from = true;
} else {
if(from) {
this.fromDate = dayOfMonth + "." + monthOfYear + "." + year;
this.from = false;
this.showDatePicker(this.getResources().getString(R.string.text_to));
} else {
this.toDate = dayOfMonth + "." + monthOfYear + "." + year;
this.from = true;
this.getMeasureData(this.fromDate, this.toDate);
}
}
}
@Override
public void onMeasureDataGetCompleted(StatusMeasureDataGet status, MeasureDataGetPOJO measureDataGetPOJO) {
switch(status) {
case MEASUREDATA_TRANSFERED: {
if(this.favourite) {
this.sessionMeasureDataListFavouriteSingleton.setMeasureDataList(measureDataGetPOJO);
} else {
this.sessionMeasureDataListSingleton.setMeasureDataList(measureDataGetPOJO);
this.saveLastMeasureData();
}
this.fragmentBecameVisible();
} break;
case ERROR_CONNECTION_FAILED: {
String title = this.getResources().getString(R.string.text_error);
String message = this.getResources().getString(R.string.text_connection_failed);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
case ERROR_IO_EXCEPTION: {
String title = this.getResources().getString(R.string.text_error);
String message = this.getResources().getString(R.string.text_io_exception);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
case ERROR_JSON_EXCEPTION: {
String title = this.getResources().getString(R.string.text_error);
String message = this.getResources().getString(R.string.text_json_exception);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
case ERROR_NO_DATA_FOUND: {
String title = this.getResources().getString(R.string.text_error);
String message = this.getResources().getString(R.string.text_not_data_found);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
case ERROR_PROTOCOL_EXCEPTION: {
String title = this.getResources().getString(R.string.text_error);
String message = this.getResources().getString(R.string.text_protocol_exception);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
case ERROR_WRONG_PARAMETERS: {
String title = this.getResources().getString(R.string.text_error);
String message = this.getResources().getString(R.string.text_wrong_parameters);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
case ERROR_WRONG_USER_OR_PW: {
String title = this.getResources().getString(R.string.text_input_error);
String message = this.getResources().getString(R.string.text_wrong_mail_or_pw);
DialogManager.showAlertDialog(title, message, this.getFragmentManager());
} break;
}
}
private void fragmentBecameVisible() {
this.initAdapter();
if(this.measureDataListAdapter != null) {
this.measureDataListAdapter.notifyDataSetChanged();
}
}
/**
*
*/
protected void initAdapter() {
this.measureDataListEntries.clear();
if(this.favourite) {
measureDataList = this.sessionMeasureDataListFavouriteSingleton.getMeasureDataList();
} else {
measureDataList = this.sessionMeasureDataListSingleton.getMeasureDataList();
}
Collections.sort(measureDataList.getMeasureDataListEntries());
for(MeasureDataListEntry measureDataListEntry : measureDataList.getMeasureDataListEntries()) {
this.measureDataListEntries.add(measureDataListEntry);
}
}
protected void saveLastMeasureData() {
String email = this.getEmail();
MeasureDataListEntry measureData = this.sessionMeasureDataPreferences.getMeasureData(this.getEmail());
int index = (this.sessionMeasureDataListSingleton.getMeasureDataList().getMeasureDataListEntries().size() - 1);
MeasureDataListEntry measureDataListEntry = this.sessionMeasureDataListSingleton.getMeasureDataList().getMeasureDataListEntries().get(index);
if(measureDataListEntry.compareTo(measureData) > 0) {
this.sessionMeasureDataPreferences.setMeasureData(email, measureDataListEntry);
}
}
protected void getMeasureData(final String fromDate, final String toDate) {
String email = this.getEmail();
String password = this.getPassword();
FragmentTransaction fragmentTransaction = this.getFragmentManager().beginTransaction();
MeasureDataGetTask measureDataGetTask = new MeasureDataGetTask(email, password, fromDate, toDate);
MeasureDataGetDialogFragment measureDataGetDialogFragment = new MeasureDataGetDialogFragment(measureDataGetTask, this);
measureDataGetDialogFragment.show(fragmentTransaction, null);
}
protected void showDatePicker(String title) {
FragmentTransaction fragmentTransaction = this.getFragmentManager().beginTransaction();
DatePickerDialogFragment datePickerDialogFragment = new DatePickerDialogFragment(this, title);
datePickerDialogFragment.show(fragmentTransaction, null);
}
}
现在问题
当我用数据填充列表时，一切似乎都没问题，它包含19个条目。只有列表的最后一个条目包含图像。只要我不滚动到最后一个条目与图像一切都保持不变。
但是在我用图像滚动到最后一个条目之后，数据以某种方式完全混淆了。当我现在突然再次向上滚动时，第4个第9个和第14个条目包含一个图像和完全相同的图像，如最后一个条目（两个条目不应包含相同的图像）。
所以我的问题是：滚动到带有图像的条目后，列表怎么可能被破坏？如何将最后一个条目的图像突然复制到其他条目？
答案 0 :(得分：2)
您只需在else方法中添加getView()语句，如下所示：
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final MeasureDataListEntry entry = this.getItem(position);
//every thing like before...
if(imageFile != null) {
viewHolder.imageButtonMeal.setVisibility(ImageButton.VISIBLE);
}else{
viewHolder.imageButtonMeal.setVisibility(ImageButton.INVISIBLE); //or GONE
}
return convertView;
}
之所以发生这种情况，是因为当您显示最后一行时VISIBLE imageView但在其他行中从未显示INVISIBLE，所以当您访问最后一行时，其可见性更改为VISIBLE并且对于其他行也是如此
答案 1 :(得分：0)
您可以尝试更改
吗？if(imageFile != null) {
viewHolder.imageButtonMeal.setVisibility(ImageButton.VISIBLE);
}
到
if(imageFile != null) {
viewHolder.imageButtonMeal.setVisibility(ImageButton.VISIBLE);
}else{
viewHolder.imageButtonMeal.setVisibility(ImageButton.GONE);
}