Android customAdapter (BasesAdapter) getView总是返回0
Android customAdapter (BasesAdapter) getView总是返回0
提问于 2015-04-22 05:46:47
我已经为listview创建了一个自定义适配器，但是由于某种原因，getView方法的参数"position“总是为0，这使得该方法非常无用。
下面是我的扩展BaseAdapter的customAdapter代码：
public class CreateProgramAdapter extends BaseAdapter {
private LayoutInflater inflater;
private ArrayList<TrainingPass> trainingPasses;
private List<TrainingPass> items;
private Context context;
public CreateProgramAdapter(Context context, List<TrainingPass> items) {
this.context = context;
this.items = items;
this.inflater = LayoutInflater.from(this.context);
}
@Override
public int getCount() {
return items.size();
}
@Override
public TrainingPass getItem(int position) {
return items.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
TrainingPassHolder holder;
if(convertView == null) {
view = inflater.inflate(R.layout.adapter_createprogram_trainingpasses_item, parent, false);
holder = new TrainingPassHolder();
System.out.println(position);
holder.trainingPass = this.getItem(position);
holder.trainingPassContainer = (RelativeLayout) view.findViewById(R.id.trainingPassContainer);
holder.trainingPassHeadlineShowHide = (TextView) view.findViewById(R.id.trainingpass_headline);
holder.noExercisesYet = (TextView) view.findViewById(R.id.txt_no_exercises_yet);
holder.exerciseSearchField = (EditText) view.findViewById(R.id.trainingpass_exercise_searchfield);
holder.trainingPassSetsListView = (ListView) view.findViewById(R.id.trainingpass_sets_listview);
holder.exercisesListView = (ListView) view.findViewById(R.id.exercises_listview);
holder.addSetButton = (Button) view.findViewById(R.id.add_set_button);
holder.addExerciseButton = (Button) view.findViewById(R.id.add_exercise_button);
holder.trainingPassContainer.setTag(holder.trainingPass);
holder.trainingPassHeadlineShowHide.setTag(holder.trainingPass);
holder.noExercisesYet.setTag(holder.trainingPass);
holder.exerciseSearchField.setTag(holder.trainingPass);
holder.trainingPassSetsListView.setTag(holder.trainingPass);
holder.exercisesListView.setTag(holder.trainingPass);
holder.addSetButton.setTag(holder.trainingPass);
holder.addExerciseButton.setTag(holder.trainingPass);
view.setTag(holder);
} else {
view = convertView;
holder = (TrainingPassHolder)view.getTag();
}
setupItems(holder);
return view;
}
private void setupItems(TrainingPassHolder trainingPassHolder) {
int id = trainingPassHolder.trainingPass.trainingPassID;
TextView showHide = trainingPassHolder.trainingPassHeadlineShowHide;
showHide.setText("Trainingpass " + id);
}
private class TrainingPassHolder {
TrainingPass trainingPass;
RelativeLayout trainingPassContainer;
TextView trainingPassHeadlineShowHide;
TextView noExercisesYet;
EditText exerciseSearchField;
ListView trainingPassSetsListView;
ListView exercisesListView;
Button addSetButton;
Button addExerciseButton;
}
}正如你所看到的，我正在同步位置，它总是0！
下面是列表视图中项目的xml layput：
<?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="wrap_content"
android:layout_gravity="center_horizontal"
android:orientation="horizontal"
android:padding="10dp">
<TextView
android:id="@+id/trainingpass_headline"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="false"
android:layout_alignParentTop="true"
android:text="Trainingpass"
android:textSize="18dp"
android:textColor="@android:color/white"
android:background="@android:color/holo_blue_dark"
android:height="35dp"
android:gravity="center_vertical"
android:paddingLeft="10dp"
android:textIsSelectable="true"
android:textStyle="bold"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="10dp" />
<ImageView
android:id="@+id/trainingpass_showhide_imageview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/abc_spinner_mtrl_am_alpha"
android:background="@android:color/holo_blue_dark"
android:height="30dp"
android:minWidth="50dp"
android:layout_alignParentTop="true"
android:layout_above="@+id/trainingPassContainer"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="10dp" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="@+id/trainingpass_headline"
android:layout_alignLeft="@+id/trainingpass_headline"
android:layout_alignStart="@+id/trainingpass_headline"
android:id="@+id/trainingPassContainer"
android:background="@color/blue_bg_neutral"
android:layout_marginBottom="10dp"
android:visibility="visible">
<EditText
android:id="@+id/trainingpass_exercise_searchfield"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="Name of exercise"
android:padding="6dp"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:background="@color/blue_bg_inputField"
android:layout_margin="10dp" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/trainingpass_exercise_searchfield"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:id="@+id/sets_container"
android:background="@color/blue_bg_inputField"
android:layout_margin="10dp"
android:padding="10dp">
<TextView
android:id="@+id/txt_sets_for_exercise"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Sets for exercise"
android:textSize="14dp"
android:textColor="@android:color/black"
android:paddingRight="30dp"
android:paddingLeft="0dp"
android:paddingTop="0dp"
android:paddingBottom="10dp"
android:textStyle="bold"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignRight="@+id/add_set_button"
android:layout_alignEnd="@+id/add_set_button" />
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/trainingpass_sets_listview"
android:nestedScrollingEnabled="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignBottom="@+id/txt_sets_for_exercise"
android:layout_below="@+id/txt_sets_for_exercise" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add set"
android:id="@+id/add_set_button"
android:layout_below="@+id/trainingpass_sets_listview"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add exercise"
android:id="@+id/add_exercise_button"
android:layout_below="@+id/add_set_button"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RelativeLayout>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_below="@+id/sets_container"
android:id="@+id/exercises_container"
android:background="@color/blue_bg_inputField"
android:layout_margin="10dp"
android:padding="10dp">
<TextView
android:id="@+id/txt_exercises"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Exercises"
android:textSize="14dp"
android:textColor="@android:color/black"
android:paddingRight="30dp"
android:paddingLeft="0dp"
android:paddingTop="0dp"
android:paddingBottom="10dp"
android:textStyle="bold"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignRight="@+id/txt_no_exercises_yet"
android:layout_alignEnd="@+id/txt_no_exercises_yet" />
<TextView
android:id="@+id/txt_no_exercises_yet"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="No exercises yet"
android:textSize="14dp"
android:textColor="@android:color/black"
android:paddingRight="30dp"
android:paddingLeft="10dp"
android:paddingTop="20dp"
android:paddingBottom="10dp"
android:layout_below="@+id/txt_exercises"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/exercises_listview"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignTop="@+id/txt_no_exercises_yet"
android:layout_above="@+id/txt_no_exercises_yet" />
</RelativeLayout>
</RelativeLayout>
</RelativeLayout>下面是我调用CreateProgramAdapter的代码：
ArrayList<TrainingPass> trainingPasses = new ArrayList<TrainingPass>();
TrainingPass trainingPass = new TrainingPass();
trainingPass.trainingPassName = "wefwef";
trainingPass.trainingPassID = 1;
TrainingPass trainingPass2 = new TrainingPass();
trainingPass2.trainingPassName = "rwefhtr";
trainingPass2.trainingPassID = 2;
trainingPasses.add(trainingPass);
trainingPasses.add(trainingPass2);
ListView trainingPassesListView = (ListView)findViewById(R.id.listView_trainingpasses);
CreateProgramAdapter createProgramAdapter = new CreateProgramAdapter(CreateProgramActivity.this, trainingPasses);
trainingPassesListView.setAdapter(createProgramAdapter);无论在列表视图中插入多少项，适配器在getView方法中的位置始终为0。显然，我希望它只为第一项返回0，然后返回1和2，依此类推，我不知道为什么不这样做。
如果需要更多的信息来解决这个问题，请尽管问。任何帮助都将不胜感激。
编辑：
我刚刚发现了一件非常奇怪的事情。我尝试将另一项添加到列表中，如下所示：
TrainingPass trainingPass3 = new TrainingPass();
trainingPass3.trainingPassName = "ffffrwwewefefhtr";
trainingPass3.trainingPassID = 3;这样做的结果与之前完全相同。在终端中只有2个Syso，写出0(位置变量)。此外，尽管我在适配器中添加了3个条目，但列表视图中只有2个条目。
这一定意味着对一个项目调用getview两次，然后不调用其余的项目。
但我还是不知道为什么会发生这样的事情。
回答 4
Stack Overflow用户
发布于 2016-10-08 23:38:39
如果您将ListView放入ScrollView中，则会发生此错误。ListView本身会进行垂直滚动，因此不能将其放入ScrollView。
当listView需要显示新项目时，适配器将调用getView。因此，如果listView不滚动，则不会创建新项，也不会调用getView。
Stack Overflow用户
发布于 2015-04-22 05:51:19
替换这个
@Override
public long getItemId(int position) {
return 0;
}有了这个
@Override
public long getItemId(int position) {
return position;
}Edit2:与我的baseadapter进行比较，我建议如下
替换这个
holder.trainingPass = this.getItem(position);通过这个
holder.trainingPass = items.getItem(position);Stack Overflow用户
发布于 2015-04-22 14:13:53
在对CreateProgramAdapter，的调用中，我怀疑您没有为适配器传递正确的上下文。更改自：
new CreateProgramAdapter(CreateProgramActivity.this, ...至：
new CreateProgramAdapter(getActivity(), ...注意：
- CreateProgramActivity的作用域必须是静态的，但我觉得它并不总是正确的活动，有时它更具动态性。如果代码在片段中，则Method getActivity更准确、更容易执行。然而，获取正确的活动可能很困难。让我们试一试，看看...
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/29783732
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