我有一个自定义ListView适配器，用于显示用户收到的好友请求。对于每一行，都有一个“接受”按钮。当用户点击该按钮时，我在更新数据库时用进度条替换该按钮。完成此过程后，我想删除该行。
嗯，这几乎就是这样。
为了显示进度条，我将按钮的可见性更改为不可见，并且可以看到进度条的可见性。
正确删除行，数据库会相应更新。问题是，在我调用notifyDataSetChanged方法后，唯一删除的行是最后一行。
这是我的代码段的更新版本：
public class FriendRequestsReceived_UserListAdapter extends GeneralListAdapter {
private List<User> friendRequestsReceived_UserList;
public FriendRequestsReceived_UserListAdapter(Context context, int resource, List<User> items) {
super(context, resource, items);
this.friendRequestsReceived_UserList=items;
}
private class ViewHolder {
TextView userEmail_TextView;
TextView name_TextView;
Button acceptBtn;
ProgressBar acceptProgressBar;
User user;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
ViewHolder holder;
LayoutInflater inflater = LayoutInflater.from(getContext());
if (view == null) {
view = inflater.inflate(R.layout.friend_requests_received_listview_row, parent, false);
holder = new ViewHolder();
holder.userEmail_TextView = (TextView) view.findViewById(R.id.user_email);
holder.name_TextView = (TextView) view.findViewById(R.id.user_name);
holder.acceptBtn = (Button) view.findViewById(R.id.acceptRequestBtn);
holder.acceptProgressBar = (ProgressBar) view.findViewById(R.id.acceptProgressBar);
holder.user = (User) getItem(position);
view.setTag(holder);
} else
holder = (ViewHolder) view.getTag();
if (holder.user!=null) {
holder.userEmail_TextView.setText(holder.user.getEmail());
holder.name_TextView.setText(holder.user.getName());
holder.acceptBtn.setTag(holder);
holder.acceptBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
acceptRequest(view);
}
});
}
return view;
}
private void acceptRequest(View acceptButtonView){
final ViewHolder vh = (ViewHolder) acceptButtonView.getTag();
vh.acceptProgressBar.setVisibility(View.VISIBLE);
vh.acceptBtn.setVisibility(View.INVISIBLE);
//Some code for updating database's related variables...
mDatabase.updateChildren(dataForDatabase, new DatabaseReference.CompletionListener() {
@Override
public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {
if (databaseError != null) showConnectionErrorToast();
else {
Toast.makeText(getContext(), "Success", Toast.LENGTH_SHORT).show();
friendRequestsReceived_UserList.remove(vh.user);
notifyDataSetChanged();
}
}
});
}
}
我正在附加此活动的视频，以显示问题：https://www.youtube.com/watch?v=9JoJ3RuRwsY
编辑：最新且有效的代码：
public class FriendRequestsReceived_UserListAdapter extends GeneralListAdapter {
private String loggedUser;
private ConnectivityManager cm;
private List<User> friendRequestsReceived_UserList;
User working_user = null;
public FriendRequestsReceived_UserListAdapter(Context context, int resource, List<User> items) {
super(context, resource, items);
this.friendRequestsReceived_UserList=items;
}
private class ViewHolder {
Button acceptBtn;
ProgressBar acceptProgressBar;
User user;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
LayoutInflater vi = LayoutInflater.from(getContext());
view = vi.inflate(R.layout.friend_requests_received_listview_row, null);
final ViewHolder holder = new ViewHolder();
TextView userEmail_TextView = (TextView) view.findViewById(R.id.user_email);
TextView name_TextView = (TextView) view.findViewById(R.id.user_name);
Button acceptBtn = (Button) view.findViewById(R.id.acceptRequestBtn);
ProgressBar acceptProgressBar = (ProgressBar) view.findViewById(R.id.acceptProgressBar);
User myUser = (User) getItem(position);
holder.acceptBtn=acceptBtn;
holder.acceptProgressBar=acceptProgressBar;
holder.user=myUser;
acceptBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
acceptRequest(view, holder);
}
});
userEmail_TextView.setText(myUser.getEmail());
name_TextView.setText(myUser.getName());
if (holder.user == working_user) {
holder.acceptProgressBar.setVisibility(View.VISIBLE);
holder.acceptBtn.setVisibility(View.INVISIBLE);
}
else {
holder.acceptProgressBar.setVisibility(View.INVISIBLE);
holder.acceptBtn.setVisibility(View.VISIBLE);
}
return view;
}
private void acceptRequest(View acceptButtonView, final ViewHolder holder){
Context context=getContext();
working_user = holder.user;
holder.acceptProgressBar.setVisibility(View.VISIBLE);
holder.acceptBtn.setVisibility(View.INVISIBLE);
loggedUser=SaveSharedPreference.getLoggedEmail(context);
final DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference();
final String senderEmail=holder.user.getEmail();
cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (cm.getActiveNetworkInfo()!=null) {
mDatabase.child("Users").child(loggedUser).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
mDatabase.child("Users").child(senderEmail).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
Map data = new HashMap();
data.put("Users/"+loggedUser+"/friend_requests_received/"+senderEmail, null);
data.put("Users/"+loggedUser+"/friends_list/"+senderEmail,true);
mDatabase.updateChildren(data, new DatabaseReference.CompletionListener() {
@Override
public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {
if (databaseError!=null)
showConnectionErrorToast();
else {//Success
Context context=getContext();
Toast.makeText(context,
"Success", Toast.LENGTH_SHORT).show();
friendRequestsReceived_UserList.remove(holder.user);
notifyDataSetChanged();
}
}
});
}
else {
showConnectionErrorToast();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
showConnectionErrorToast();
}
});
}
else {
showConnectionErrorToast();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
showConnectionErrorToast();
}
});
}
else {
showConnectionErrorToast();
}
}
答案 0 :(得分：2)
这是我 p1 <- df[[1]] %>%
group_by(type) %>%
plot_ly(x=~factor(Index), y = ~value, color = ~type, colors = c("#132B43", "#56B1F7"), type = 'scatter', mode = 'lines')
p2 <- df[[2]] %>%
group_by(type) %>%
plot_ly(x=~factor(Index), y = ~value, color = ~type, colors = c("#132B43", "#56B1F7"), type = 'scatter', mode = 'lines', showlegend = F)
p3 <- df[[3]] %>%
group_by(type) %>%
plot_ly(x=~factor(Index), y = ~value, color = ~type, colors = c("#132B43", "#56B1F7"), type = 'scatter', mode = 'lines', showlegend = F)
subplot(p1,p2,p3,nrows=1,titleY = TRUE, shareX = TRUE, margin = c(0.085,0.01,0.1,0.1))
发生的事情（无法访问android studio atm）
假设您从两个用户user1，user2
开始当适配器初始化时，getCount返回2;
GetView运行两次，一次用于位置0，一次用于一次
这会创建两个视图view1，其中包含view1 vh1，其中包含user1 和view2-＆gt; vh2-＆gt; user2
当您按下接受时，您运行代码并设置view1的可见性
然后你调用notifydatasetchanged使整个适配器无效
getcount方法将返回1
getview方法将初始化为位置0，但将以View参数初始化（view1）开始
该参数的视图可见性设置为显示进度条并引用user1
会发生什么情况是user1从数据库中删除但它仍然存在于view1的viewholder中，并且因为getcount返回1而不再需要view2而放置了view2
这是我think应该工作的地方：
首先声明一个实例变量：
think然后
User _working_user = null;
现在上面应该可以了，但是这里有一些注意事项
我们使用_working_user，因为当数据库内容执行时，有其他东西会调用NotifyDataSetChanged（），如果没有，理论上它不应该被需要
我真的不喜欢onclick处理程序传递视图的事实，你可以调用它的个人偏好，我要做的是在if（view == null）块中声明click处理程序，然后调用accept视图持有者的用户对象
的参数