【发布时间】:2018-02-11 03:23:36
【问题描述】:
几天前我遇到了这个问题,我正在开发一个程序,其中ListView 通过自定义SimpleCursorAdapter 从数据库中获取数据,我曾经使用listView.setAdapter(adapter) 来更新@987654324 中的数据@每次更改数据时。但这会带来一个问题,每次更新数据时,listView 都会自动滚动到顶部,所以我决定改用swapCursor(),如下所示:
Cursor cursor = database.getData();
if(listView.getAdapter() == null){
//Toast.makeText(getApplicationContext(),"null",Toast.LENGTH_SHORT).show();
adapter = (new CustomSimpleCursorAdapter(this,R.layout.todolist,cursor,new String[] {LIST_TEXT},new int[]{R.id.text}));
listView.setAdapter(adapter);
}else {
Runnable runnable =new Runnable() {
@Override
public void run() {
Cursor finalCs = database.getData();
todoListAdapter.swapCursor(finalCs);
todoListAdapter.notifyDataSetChanged();
}
};
runOnUiThread(runnable);
}
但是每次我尝试将数据添加到数据库并在listView中显示时都会出现错误:
**CursorIndexOutOfBoundsException: Index 12 requested, with a size of 12**
(注意,数据是添加到数据库中的,之前使用listView.setAdapter(adapter)没有发现问题,我尝试删除todoListAdapter.notifyDataSetChanged();,但根本没有帮助。另外,当我尝试删除时数据库中的数据并使用更改更新listView,无论我选择哪一项,它始终是listView中的最后一项(现在的数据实际上已从数据库中正确删除),当我尝试再次添加数据,我现在可以添加与之前删除的数据量相同的数据量(如果我删除了 4 项,那么我只能添加 4 项,否则会出现错误)。无论如何,swapCursor()似乎在我使用它时非常糟糕,我做错了什么吗?或者我需要其他东西才能让swapCursor() 工作?提前致谢!
更新:错误回溯上下文:
android.database.CursorIndexOutOfBoundsException: Index 13 requested, with a size of 13
at android.database.AbstractCursor.checkPosition(AbstractCursor.java:460)
at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
at android.support.v4.widget.SimpleCursorAdapter.bindView(SimpleCursorAdapter.java:139)
更新:自定义SimpleCursorAdapter:
import android.content.Context;
import android.database.Cursor;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.TextView;
import java.util.ArrayList;
public class TodoListAdapter extends SimpleCursorAdapter {
private Cursor c;
private Context context;
private ArrayList<Long> itemChecked = new ArrayList<>();
protected int[] mFrom;
protected int[] mTo;
LayoutInflater inflater;
private int mStringConversionColumn = -1;
private CursorToStringConverter mCursorToStringConverter;
private ViewBinder mViewBinder;
MainActivity main;
String[] mOriginalFrom;
public TodoListAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
super(context, layout, c, from, to,1);
this.c = c;
this.context = context;
mTo = to;
mOriginalFrom = from;
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public ViewBinder getViewBinder() {
return mViewBinder;
}
public ArrayList returnSelected(){
return itemChecked;
}
public interface MyInterface{
public void foo();
}
public void setViewBinder(ViewBinder viewBinder) {
mViewBinder = viewBinder;
}
public View getView(final int pos, View inView, ViewGroup parent) {
c.moveToPosition(pos);
if (inView == null) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inView = inflater.inflate(R.layout.todolist, null);
}
final TextView todoText = (TextView) inView.findViewById(R.id.titleText);
final CheckBox cBox = (CheckBox) inView.findViewById(R.id.multiSelectionBox);
System.out.println(c.getCount());
newView(context,c,parent);
bindView(inView,context,c);
final long id = getItemId(pos);
cBox.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
CheckBox cb = (CheckBox) v.findViewById(R.id.multiSelectionBox);
if (cb.isChecked()) {
if(context.toString().contains("MainActivity")){
((MainActivity)context).addSelectedId(id);
}else if(context.toString().contains("HistoryActivity")){
((HistoryActivity)context).addSelectedId(id);
}
System.out.println("checked " + id);
} else if (!cb.isChecked()) {
System.out.println("unchecked " + id);
if(context.toString().contains("MainActivity")){
((MainActivity)context).removeSelectedId(id);
}else if(context.toString().contains("HistoryActivity")){
((HistoryActivity)context).removeSelectedId(id);
}
}
}
});
return inView;
}
}
【问题讨论】:
-
发布整个回溯 - 或至少最后 4-5 帧
-
我做到了,尽管我认为这个问题的回溯没有那么有用...
-
发布 SimpleCursorAdapter 和 swapCursor 代码
-
好的,所以发布您的自定义
SimpleCursorAdapter代码 -
例如你是否重写了
getCount方法?
标签: android listview simplecursoradapter android-cursoradapter android-cursor