Question

从FirebaseDatabase检索数据时遇到了一些麻烦。

我认为我已经以正确的方式完成了所有事情，但仍然会弹出此错误并导致应用崩溃。

com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.rana.sahaj.myyu.profile.ExtraProfilClass

ExtraProfilClass

@IgnoreExtraProperties
public class ExtraProfilClass {
private String branch;
private String campus;
private String course;
private String gplusURL;
private String hashname;
private String picurl;
private String picurl50DP;
private String userEmail;
private String userNAME;
private String yearFrom;
private String yearTo;
public ExtraProfilClass(){
    //Empty constructor for firebase
}


public ExtraProfilClass(String branch, String campus, String course, String gplusURL, String hashname, String picurl, String picurl50DP, String userEmail, String userNAME, String yearFrom, String yearTo) {
    this.branch = branch;
    this.campus = campus;
    this.course = course;
    this.gplusURL = gplusURL;
    this.hashname = hashname;
    this.picurl = picurl;
    this.picurl50DP = picurl50DP;
    this.userEmail = userEmail;
    this.userNAME = userNAME;
    this.yearFrom = yearFrom;
    this.yearTo = yearTo;
}

public String getBranch() {
    return branch;
}

public void setBranch(String branch) {
    this.branch = branch;
}

public String getCampus() {
    return campus;
}

public void setCampus(String campus) {
    this.campus = campus;
}

public String getCourse() {
    return course;
}

public void setCourse(String course) {
    this.course = course;
}

public String getGplusURL() {
    return gplusURL;
}

public void setGplusURL(String gplusURL) {
    this.gplusURL = gplusURL;
}

public String getHashname() {
    return hashname;
}

public void setHashname(String hashname) {
    this.hashname = hashname;
}

public String getPicurl() {
    return picurl;
}

public void setPicurl(String picurl) {
    this.picurl = picurl;
}

public String getPicurl50DP() {
    return picurl50DP;
}

public void setPicurl50DP(String picurl50DP) {
    this.picurl50DP = picurl50DP;
}

public String getUserEmail() {
    return userEmail;
}

public void setUserEmail(String userEmail) {
    this.userEmail = userEmail;
}

public String getUserNAME() {
    return userNAME;
}

public void setUserNAME(String userNAME) {
    this.userNAME = userNAME;
}

public String getYearFrom() {
    return yearFrom;
}

public void setYearFrom(String yearFrom) {
    this.yearFrom = yearFrom;
}

public String getYearTo() {
    return yearTo;
}

public void setYearTo(String yearTo) {
    this.yearTo = yearTo;
}
}

和检索的代码是

 @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String s) {
      // Map<String, String> msg = (HashMap<String, String>)dataSnapshot.getValue();
 -->       ExtraProfilClass extraProfilClass=dataSnapshot.getValue(ExtraProfilClass.class);

    //    String userEmail_here=extraProfilClass.getUserEmail();
   //     userEmailKey = userEmail_here.substring(0, userEmail_here.length() - 10);

所以......我解决了这个问题。我没有使用正确的节点引用，我的错误

（按照Shubhank的要求修复）

问题是我想获得user1的个人资料节点

public static DatabaseReference mFirebaseRef = FirebaseDatabase.getInstance().getReferenceFromUrl(constants.FIREBASE_URL+"app/authGplus/users/");

所以我做的是： mFirebaseRef.child(UserToWhichProfileIsNeeded).child("profile").addChildEventListener(listener);

但我打电话给addChildEventListener

它已经引用子节点所以我不需要在引用期间放置.child("profile")，它会变成这样，

mFirebaseRef.child(UserToWhichProfileIsNeeded).addChildEventListener(listener);

然后它工作正常。

Answer 1

首先将dataSnapshot转换为Map<String, Object>，然后将其转换为ExtraProfilClass

Map<String, Object> map = (HashMap<String, Object>) dataSnapshot.getValue();

com.google.firebase.database.DatabaseException：无法将java.lang.String类型的对象转换为type

1 个答案: