我想显示具有 4 种不同布局类型的通知列表。会有4种类型的通知chat_noti,share_noti,coorganizer_noti,invitation_noti。 这 4 种类型有 4 种不同的布局。我想在 recyclerview 中显示这个。
这是我的适配器:
编辑:
List<Notifications> notificationsList;
Context context;
private static final int INVITATION_NOTI = 0;
private static final int CHAT_NOTI = 1;
private static final int SHARE_NOTI = 2;
private static final int COORGANIZER_NOTI = 3;
private int selectedPos = 0;
public NotificationsAdapter(Context context,List<Notifications> notificationsList){
this.notificationsList = notificationsList;
this.context = context;
}
@Override
public int getItemViewType(int type) {
if (type == 0)
{
return INVITATION_NOTI;
}
else if(type == 1)
{
return CHAT_NOTI;
}
else if(type == 2)
{
return SHARE_NOTI;
}
else if (type == 3)
{
return COORGANIZER_NOTI;
}
return -1;
}
@Override
public MainViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
switch (viewType){
case INVITATION_NOTI:
return new InvitationViewHolder(LayoutInflater.from(context).inflate(R.layout.invitation_notification, parent, false));
case CHAT_NOTI:
return new ChatNotificationViewHolder(LayoutInflater.from(context).inflate(R.layout.chat_notification, parent, false));
case SHARE_NOTI:
return new ShareViewHolder(LayoutInflater.from(context).inflate(R.layout.share_notification, parent, false));
case COORGANIZER_NOTI:
return new CoOrganizerViewHolder(LayoutInflater.from(context).inflate(R.layout.co_organizer_notification, parent, false));
}
return null;
}
@Override
public void onBindViewHolder(MainViewHolder holder, int position) {
if(holder.getItemViewType() == INVITATION_NOTI){
InvitationViewHolder mholder = (InvitationViewHolder) holder;
}
else if(holder.getItemViewType() == CHAT_NOTI){
ChatNotificationViewHolder mholder = (ChatNotificationViewHolder) holder;
}
else if(holder.getItemViewType() == SHARE_NOTI){
ShareViewHolder mholder = (ShareViewHolder) holder;
}
else if(holder.getItemViewType() == COORGANIZER_NOTI){
CoOrganizerViewHolder mholder = (CoOrganizerViewHolder) holder;
}
}
@Override
public int getItemCount() {
return notificationsList.size();
}
public class InvitationViewHolder extends MainViewHolder{
TextView text,event,question;
Button yes,no;
public InvitationViewHolder(View v){
super(v);
this.text = (TextView) v.findViewById(R.id.text);
this.event = (TextView) v.findViewById(R.id.eventType);
this.question = (TextView) v.findViewById(R.id.question);
this.yes = (Button) v.findViewById(R.id.yes);
this.no = (Button) v.findViewById(R.id.no);
}
}
public class ChatNotificationViewHolder extends MainViewHolder{
TextView text,sender;
public ChatNotificationViewHolder(View v){
super(v);
this.text = (TextView) v.findViewById(R.id.text);
this.sender = (TextView) v.findViewById(R.id.sender);
}
}
public class ShareViewHolder extends MainViewHolder{
TextView text;
public ShareViewHolder(View v){
super(v);
this.text = (TextView) v.findViewById(R.id.text);
}
}
public class CoOrganizerViewHolder extends MainViewHolder{
TextView text;
Button view;
public CoOrganizerViewHolder(View v){
super(v);
this.text = (TextView) v.findViewById(R.id.text);
this.view = (Button) v.findViewById(R.id.view);
}
}
public class MainViewHolder extends RecyclerView.ViewHolder {
public MainViewHolder(View v) {
super(v);
}
}
登录目录:
FATAL EXCEPTION: main Process: com.example.siddhi.meavita, PID: 22717 java.lang.NullPointerException: Attempt to write to field 'int android.support.v7.widget.RecyclerView$ViewHolder.mItemViewType' on a null object reference at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:5483) at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4707) at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617) at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994) at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390) at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
我尝试使用此代码,它会为 View 类型抛出空指针异常。
应根据通知类型显示布局。我怎样才能做到这一点? 谢谢..
我正在添加这样的项目:
private void prepareData() {
Notifications notifications = new Notifications("You have an Invitation.","Michell's Marraige","Attending?","",0);
notificationsList.add(notifications);
notifications = new Notifications("You have an Invitation.","Kate's Reception","Attending?","",0);
notificationsList.add(notifications);
notifications = new Notifications("Vishal Say's","","Have you attended wedding?","",1);
notificationsList.add(notifications);
notifications = new Notifications("Siddhi Say's","","Have you gone for shopping?","",1);
notificationsList.add(notifications);
notifications = new Notifications("Ashmit shared a photo with you","","","",2);
notificationsList.add(notifications);
notifications = new Notifications("Neeta shared a photo with you","","","",2);
notificationsList.add(notifications);
notifications = new Notifications("You are a co-organizer for My Birthaday","","","",3);
notificationsList.add(notifications);
notifications = new Notifications("You are a co-organizer for My Wedding","","","",3);
notificationsList.add(notifications);
mAdapter.notifyDataSetChanged();
}
最后一个属性是通知类型。
最佳答案
此错误是在 getItemViewType()
返回一个 onCreateViewHolder
尚未为其分配 View 持有者的值时引起的。我感觉正在发生的事情是 getItemViewType()
返回 -1 以获得某些值。现在 onCreateViewHolder()
不知道当 viewType == -1
时要做什么。因此,您会收到错误消息。
关于java - 如何在 recyclerView 中显示不同的布局?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37589102/