Android 尝试调用虚拟方法'；java.lang.String example.asuspc.prospect.model.UserModel.getPhoto_profile（）'；关于空对象引用
我对Android很陌生，但我已经多次遇到这个错误，只是这次我没有解决它的线索。这是我目前正在开发的一个即时聊天应用程序的示例代码 首先是错误：Android 尝试调用虚拟方法'；java.lang.String example.asuspc.prospect.model.UserModel.getPhoto_profile（）'；关于空对象引用,android,Android,我对Android很陌生，但我已经多次遇到这个错误，只是这次我没有解决它的线索。这是我目前正在开发的一个即时聊天应用程序的示例代码 首先是错误： 01-24 18:57:22.267 30531-30531/example.asuspc.prospect E/AndroidRuntime: FATAL EXCEPTION: main Process:
01-24 18:57:22.267 30531-30531/example.asuspc.prospect E/AndroidRuntime: FATAL EXCEPTION: main
Process: example.asuspc.prospect, PID: 30531
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String example.asuspc.prospect.model.UserModel.getPhoto_profile()' on a null object reference
at example.asuspc.prospect.ChatFirebaseAdapter.populateViewHolder(ChatFirebaseAdapter.java:90)
at example.asuspc.prospect.ChatFirebaseAdapter.populateViewHolder(ChatFirebaseAdapter.java:28)
at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:177)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5471)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5504)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4741)
at android.support.v7.widget.RecyclerView$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)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:549)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2906)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3283)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:435)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:15761)
at android.view.ViewGroup.layout(ViewGroup.java:5039)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2090)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1847)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1065)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5901)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Lo
public class ChatFirebaseAdapter extends FirebaseRecyclerAdapter<ChatModel,ChatFirebaseAdapter.MyChatViewHolder> {
private static final int RIGHT_MSG = 0;
private static final int LEFT_MSG = 1;
private static final int RIGHT_MSG_IMG = 2;
private static final int LEFT_MSG_IMG = 3;
private ClickListenerChatFirebase mClickListenerChatFirebase;
private String nameUser;
public ChatFirebaseAdapter(DatabaseReference ref, String nameUser,ClickListenerChatFirebase mClickListenerChatFirebase) {
super(ChatModel.class, R.layout.item_message_left, ChatFirebaseAdapter.MyChatViewHolder.class, ref);
this.nameUser = nameUser;
this.mClickListenerChatFirebase = mClickListenerChatFirebase;
}
@Override
public MyChatViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view;
if (viewType == RIGHT_MSG){
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_message_right,parent,false);
return new MyChatViewHolder(view);
}else if (viewType == LEFT_MSG){
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_message_left,parent,false);
return new MyChatViewHolder(view);
}else if (viewType == RIGHT_MSG_IMG){
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_message_right_img,parent,false);
return new MyChatViewHolder(view);
}else{
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_message_left_img,parent,false);
return new MyChatViewHolder(view);
}
}
@Override
public int getItemViewType(int position) {
ChatModel model = getItem(position);
if (model.getMapModel() != null){
if (model.getUserModel().getName().equals(nameUser)){
return RIGHT_MSG_IMG;
}else{
return LEFT_MSG_IMG;
}
}else if (model.getFile() != null){
if (model.getFile().getType().equals("img") && model.getUserModel().getName().equals(nameUser)){
return RIGHT_MSG_IMG;
}else{
return LEFT_MSG_IMG;
}
}else if (model.getUserModel() !=null){
if (model.getUserModel().getName().equals(nameUser));
return RIGHT_MSG;
}else{
return LEFT_MSG;
}
}
@Override
protected void populateViewHolder(MyChatViewHolder viewHolder, ChatModel model, int position) {
viewHolder.setIvUser(model.getUserModel().getPhoto_profile());
viewHolder.setTxtMessage(model.getMessage());
viewHolder.setTvTimestamp(model.getTimeStamp());
viewHolder.tvIsLocation(View.GONE);
if (model.getFile() != null){
viewHolder.tvIsLocation(View.GONE);
viewHolder.setIvChatPhoto(model.getFile().getUrl_file());
}else if(model.getMapModel() != null){
viewHolder.setIvChatPhoto(example.asuspc.prospect.Util.local(model.getMapModel().getLatitude(),model.getMapModel().getLongitude()));
viewHolder.tvIsLocation(View.VISIBLE);
}
}
public class MyChatViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView tvTimestamp,tvLocation;
EmojiconTextView txtMessage;
ImageView ivUser,ivChatPhoto;
public MyChatViewHolder(View itemView) {
super(itemView);
tvTimestamp = (TextView)itemView.findViewById(R.id.timestamp);
txtMessage = (EmojiconTextView)itemView.findViewById(R.id.txtMessage);
tvLocation = (TextView)itemView.findViewById(R.id.tvLocation);
ivChatPhoto = (ImageView)itemView.findViewById(R.id.img_chat);
ivUser = (ImageView)itemView.findViewById(R.id.ivUserChat);
}
@Override
public void onClick(View view) {
int position = getAdapterPosition();
ChatModel model = getItem(position);
if (model.getMapModel() != null){
mClickListenerChatFirebase.clickImageMapChat(view,position,model.getMapModel().getLatitude(),model.getMapModel().getLongitude());
}else{
mClickListenerChatFirebase.clickImageChat(view,position,model.getUserModel().getName(),model.getUserModel().getPhoto_profile(),model.getFile().getUrl_file());
}
}
public void setTxtMessage(String message){
if (txtMessage == null)return;
txtMessage.setText(message);
}
public void setIvUser(String urlPhotoUser){
if (ivUser == null)return;
Glide.with(ivUser.getContext()).load(urlPhotoUser).centerCrop().transform(new CircleTransform(ivUser.getContext())).override(40,40).into(ivUser);
}
public void setTvTimestamp(String timestamp){
if (tvTimestamp == null)return;
tvTimestamp.setText(converteTimestamp(timestamp));
}
public void setIvChatPhoto(String url){
if (ivChatPhoto == null)return;
Glide.with(ivChatPhoto.getContext()).load(url)
.override(100, 100)
.fitCenter()
.into(ivChatPhoto);
ivChatPhoto.setOnClickListener(this);
}
public void tvIsLocation(int visible){
if (tvLocation == null)return;
tvLocation.setVisibility(visible);
}
}
private CharSequence converteTimestamp(String mileSegundos){
return DateUtils.getRelativeTimeSpanString(Long.parseLong(mileSegundos),System.currentTimeMillis(), DateUtils.SECOND_IN_MILLIS);
}
如果有人能帮忙，我将非常感激：）UserModel是null@AntonKazakov那我该怎么解决呢？可能是
public class UserModel {
private String id;
private String name;
private String photo_profile;
public UserModel() {
}
public UserModel(String name, String photo_profile, String id) {
this.name = name;
this.photo_profile = photo_profile;
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhoto_profile() {
return photo_profile;
}
public void setPhoto_profile(String photo_profile) {
this.photo_profile = photo_profile;
}
@Exclude
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}