ListView问题？

Question

我正在使用列表视图请求android的权限。我创建了一个自定义适配器。问题在于，在列表视图中，只有适配器数组的第一个元素是可见的（TextView），其余项是不可见的。

下面是代码参考：

自定义适配器：

private class ListViewAdapter extends ArrayAdapter<String>{
        private int layout;

        private ListViewAdapter(Context context, int resource, List<String> objects){
            super(context,resource,objects);
            layout = resource;
        }

        @NonNull
        @Override
        public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
            ViewHolder mainViewHolder = null;
            if(convertView == null){
                LayoutInflater inflater = LayoutInflater.from(getContext());
                convertView = inflater.inflate(layout,parent,false);
                ViewHolder holder = new ViewHolder();
                holder.textView = (TextView)convertView.findViewById(R.id.permision_list_view_text);
                holder.switchCompat = (SwitchCompat)convertView.findViewById(R.id.permision_list_view_switch);
                convertView.setTag(holder);
            }else{
                mainViewHolder = (ViewHolder)convertView.getTag();
                mainViewHolder.textView.setText(getItem(position));
            }
            return convertView;
        }

    }

初始化列表视图：

@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_permission_request_dialog, container, false);
        ListView lv = (ListView)view.findViewById(R.id.permission_request_list_view);
        getPermissionArray();
        Log.d("permissions",permissions.toString());
        lv.setAdapter(new ListViewAdapter(getContext(),R.layout.permission_dialog_listview_row,permissions));
        return  view;
    }

阵列适配器：

public void getPermissionArray(){
        permissions.add("Request 1");
        permissions.add("Request 2");
        permissions.add("Request 3");
    }

列表视图行项目布局：

<?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:layout_gravity="center"
    android:paddingHorizontal="20dp"
    android:paddingVertical="10dp">

    <TextView
        android:id="@+id/permision_list_view_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif-condensed"
        android:textColor="@color/colorBlack" />

    <android.support.v7.widget.SwitchCompat
        android:id="@+id/permision_list_view_switch"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true" />
</RelativeLayout>

我不明白为什么列表视图不完整。

下面是我的移动设备（Motorola G3）上问题的屏幕快照

任何帮助将不胜感激。

Answer 1

@NonNull
        @Override
        public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
            View rowView = convertView;
            if(rowView == null){
                LayoutInflater inflater = LayoutInflater.from(getContext());
                rowView = inflater.inflate(layout,parent,false);
                ViewHolder holder = new ViewHolder();
                holder.textView = (TextView)rowView.findViewById(R.id.permision_list_view_text);
                holder.switchCompat = (SwitchCompat)rowView.findViewById(R.id.permision_list_view_switch);
                rowView.setTag(holder);
            }

            ViewHolder holder = (ViewHolder) rowView.getTag();

            // Set your permission data here using holder

            return rowView;
        }

Answer 2

您将列表项的文本设置在错误的位置：

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        ViewHolder mainViewHolder = null;
        if(convertView == null){
            LayoutInflater inflater = LayoutInflater.from(getContext());
            convertView = inflater.inflate(layout,parent,false);
            ViewHolder holder = new ViewHolder();
            holder.textView = (TextView)convertView.findViewById(R.id.permision_list_view_text);
            holder.switchCompat = (SwitchCompat)convertView.findViewById(R.id.permision_list_view_switch);
            convertView.setTag(holder);
        }else{
            mainViewHolder = (ViewHolder)convertView.getTag();
            //mainViewHolder.textView.setText(getItem(position)); // not here. This else section is reached only when the rows are getting recycled. 
        }
        mainViewHolder.textView.setText(getItem(position)); // here
        return convertView;
    }

}