Question

我正在尝试在android studio中使用列表视图。

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    populateListView();

    return inflater.inflate(R.layout.stand1,container,false);

}

private void populateListView() {
    String[] pair = {"Pair1","Pair2","Pair3","Pair4","Pair5"};

    //build adapter
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.stand1,pair);

    //populate
    ListView list = (ListView) findViewById(R.id.Stand1list);
    list.setAdapter(adapter);
}}

我得到的错误是

    Error:(31, 40) error: no suitable constructor found for ArrayAdapter(Stand1,int,String[])
constructor ArrayAdapter.ArrayAdapter(Context,int,int) is not applicable
(argument mismatch; Stand1 cannot be converted to Context)
constructor ArrayAdapter.ArrayAdapter(Context,int,String[]) is not applicable
(argument mismatch; Stand1 cannot be converted to Context)
constructor ArrayAdapter.ArrayAdapter(Context,int,List<String>) is not applicable
(argument mismatch; Stand1 cannot be converted to Context)


Error:(34, 36) error: cannot find symbol method findViewById(int)

stand1是一个xml文件，Stand1List是stand1.xml

中的listview id

我知道这很简单，但对于我的生活，我不知道是什么......

对于引用，Stand1.java是java文件，它是activity_main中的一个片段。它被导航抽屉调用。

更新

感谢Jedil答案，我有点工作。但是当我加载片段说文本视图需要ID时，我遇到了错误。我没有在stand1.xml下面放一个textview。

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent">

    <ListView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/Stand1list">
        <TextView

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/tex1"
            />
       </ListView>




</FrameLayout>

现在我收到错误

 java.lang.UnsupportedOperationException: addView(View, LayoutParams) is not supported in AdapterView

Answer 1

您过早地调用populateListView()，因为您的视图尚未创建。尝试使用

中的populateListView()

public void onViewCreated (View view, Bundle savedInstanceState)

Answer 2

将ListView声明为fragment：

的成员变量

ListView list; // your ListView

而不是将其传递给您的ArrayAdapter，您需要传递getActivity()，这是主持人活动的背景。

最后，在onCreateView方法中初始化listView。

list = (ListView) findViewById(R.id.Stand1list);

<强> CODE：

ListView list; // your ListView

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.stand1,container,false);
    list = (ListView) view.findViewById(R.id.Stand1list);
    populateListView();
}

private void populateListView(View mView) { 
    String[] pair = {"Pair1","Pair2","Pair3","Pair4","Pair5"};

    //build adapter 
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), R.layout.stand1,pair);

    list.setAdapter(adapter);
}

Answer 3

您的代码是fragment实施代码。

第一个错误是关于ArrayAdapter需要Context作为第一个参数。因此，代码位置this表示fragment个对象，但您需要Context Activity，而不是使用this使用getActivity()在那些地方

ArrayAdapter<String>(getActivity(), R.layout.stand1,pair);

和

ListView list = (ListView) getActivity().findViewById(R.id.Stand1list);

那么代码应该如何：

ListView mList;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View root = inflater.inflate(R.layout.stand1,container,false);
    mList = (ListView) root.findViewById(R.id.Stand1list);
    return root;
}

public void onActivityCreated(Bundle savedInstanceState)
{
   super.onActivityCreated(savedInstanceState);
   populateListView();
}

private void populateListView() {
    String[] pair = {"Pair1","Pair2","Pair3","Pair4","Pair5"};

    //build adapter
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), R.layout.stand1,pair);

    mList.setAdapter(adapter);
}}

Answer 4

将代码更改为：

View view = null;
@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    view = inflater.inflate(R.layout.stand1,container,false);
    populateListView(view); 


    return view;

} 

private void populateListView(View mView) { 
    String[] pair = {"Pair1","Pair2","Pair3","Pair4","Pair5"};

    //build adapter 
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity().getApplicationContext(), R.layout.stand1,pair);

    //populate 
    ListView list = (ListView) mView.findViewById(R.id.Stand1list);
    list.setAdapter(adapter);
}}

Answer 5

ListView listview; // define this on class level

View view = inflater.inflate(R.layout.stand1,container,false);
 listview = view.findViewById(R.id.Stand1list);
populateListView();
retur view ;

在populateListView()中以这种方式设置适配器

 ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), R.layout.stand1,pair);

基本列表视图 - 按ID查找无效

5 个答案: