我创建了一个自定义列表，其中包含卡片视图，按钮，文本视图和开关。我已将标签设置为卡片视图。
但是当我试图在表视图持有者中检索此标记时，它会抛出一个空指针异常。
如果我在监听器中获取标签，则不会抛出任何异常。我不知道从哪里访问这个标签。
如果状态为1，我想对switch执行setChecked true，如果状态为0，则setChecked应该为false。
但我不知道该怎么办？
CustomAlertAdapter
public class TableListAdapter extends RecyclerView.Adapter<TableListAdapter.TableViewHolder> {
public static TimeTableHelper db;
public static TimeTableList timeTableList;
public static int cardId,id,status=0;
public static boolean editMode;
public static List<TimeTable> tableList;
public static TimeTable t = new TimeTable();
public static TimeTable ci;
public TableListAdapter(List<TimeTable> tableList,TimeTableList timeTableList) {
this.tableList = tableList;
this.timeTableList = timeTableList;
}
private Context context;
public TableListAdapter(Context context) {
this.context = context;
}
@Override
public int getItemCount() {
return tableList.size();
}
@Override
public void onBindViewHolder(TableViewHolder tableViewHolder, int i) {
ci = tableList.get(i);
tableViewHolder.cv.setTag(i);
tableViewHolder.aSwitch.setTag(i);
Log.d("setId", String.valueOf(i));
tableViewHolder.tableTitle.setText(ci.getTitle());
((GradientDrawable)tableViewHolder.color.getBackground()).setColor(ci.getTableColor());
}
@Override
public TableViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.
from(viewGroup.getContext()).
inflate(R.layout.table_card, viewGroup, false);
return new TableViewHolder(itemView);
}
public static class TableViewHolder extends RecyclerView.ViewHolder {
protected TextView tableTitle;
protected CardView cv;
protected SwitchCompat aSwitch;
protected Button color;
public TableViewHolder(final View v) {
super(v);
tableTitle = (TextView) v.findViewById(R.id.tableTitle);
cv = (CardView) v.findViewById(R.id.card_view);
aSwitch = (SwitchCompat) v.findViewById(R.id.switch2);
color = (Button) v.findViewById(R.id.selectColor);
db = new TimeTableHelper(timeTableList);
cv.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(final View v) {
// TODO Auto-generated method stub
final AlertDialog.Builder builder = new AlertDialog.Builder(timeTableList);
builder.setTitle("Delete Time Table")
.setMessage("Are you sure you want to Delete this Time Table?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
cardId = (int)v.getTag();
Log.d("cardId", String.valueOf(cardId));
t = tableList.get(cardId);
id = t.getId();
t = db.getTable(id);
db.deleteTable(t);
Intent intent = new Intent(timeTableList,TimeTableList.class);
timeTableList.finish();
timeTableList.startActivity(intent);
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// do nothing
}
})
.setIcon(R.drawable.ic_warning_black_36dp)
.show();
return true;
}
});
cv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View v) {
cardId = (int)v.getTag();
Log.d("cardId", String.valueOf(cardId));
t = tableList.get(cardId);
id = t.getId();
Log.d("Id",String.valueOf(id));
editMode = true;
Intent i = new Intent(timeTableList, NewTimeTable.class);
i.putExtra("editMode", editMode);
i.putExtra("tableId", id);
timeTableList.startActivity(i);
}
});
cardId = (int) cv.getTag();
Log.d("cardId", String.valueOf(cardId));
t = tableList.get(cardId);
id = t.getId();
if(status == 1)
{
aSwitch.setChecked(true);
}
else
{
aSwitch.setChecked(false);
}
aSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
status = 1;
t = db.getTable(id);
t.setStatus(status);
db.updateStatus(t);
Log.d("status", String.valueOf(status));
final List<TimeTable> events = db.getAllTables();
for (TimeTable cn : events) {
String log = "Id: " + cn.getId() + " ,Title: " + cn.getTitle() +
"Status: " + cn.getStatus() + ",color: " + cn.getTableColor();
Log.d("Data ", log);
}
} else {
status = 0;
t = db.getTable(id);
t.setStatus(status);
db.updateStatus(t);
final List<TimeTable> events = db.getAllTables();
for (TimeTable cn : events) {
String log = "Id: " + cn.getId() + " ,Title: " + cn.getTitle() +
"Status: " + cn.getStatus() + ",color: " + cn.getTableColor();
Log.d("Data ", log);
}
Log.d("status", String.valueOf(status));
}
}
});
}
}
public void updateAdapaterList(List<TimeTable> newTimeTableList) {
//Replace the current list with new list
this.tableList = newTimeTableList;
//notify the adapter that the data set has changed
notifyDataSetChanged();
}
}
谢谢。
答案 0 :(得分：1)
您应该在视图持有者中使用ID，标签或任何类型的标识符，因为您的视图持有者在回收站视图中重复使用。我相信这就是导致你麻烦的原因。
您应该使用onBindViewHolder分配和链接每个视图持有者的数据。
为了在该方法中分配侦听器和ID，您应该执行以下操作：
public void onBindViewHolder(TableViewHolder tableViewHolder, int i) {
final TimeTable ci = tableList.get(i);
//...
tableViewHolder.setOnSomethingListener() {
// You can use the ci reference here because you declared it as final
// When this view is reused and references another position, the listener will be updated on the onBindViewHolder, to reference the new position that it will be being associated with
}
}
另外，在旁注中，此类中的所有静态变量可能都不是静态的，因为如果您在其他视图中碰巧有更多的适配器实例，那么您最终不希望它们干扰每个其他
答案 1 :(得分：1)
您应该将内容分配给适配器location test/ {
rewrite serveClient.swf?^(.*)$ serveClient.php?$1;
}
中ViewHolder中引用的UI字段，而不是onBindMethod。
您的代码示例：
ViewHolder}