我正在使用Android中的Java和Firebase开发应用程序,因为我从Firebase数据库中检索数据。这是我的代码
databaseReference.orderByChild("email").equalTo(email).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
AddFaculty addFaculty = dataSnapshot1.getValue(AddFaculty.class);
department = addFaculty.getDepartment();
year = addFaculty.getYear();
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
模型类
public class AddFaculty {
private String name;
private String email;
private String position;
private String department;
private String year;
private String facultyId;
public AddFaculty() {
}
public AddFaculty(String name, String email, String position, String department, String year, String facultyId) {
this.name = name;
this.email = email;
this.position = position;
this.department = department;
this.year = year;
this.facultyId = facultyId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPosition() {
return position;
}
public void setPosition(String position) {
this.position = position;
}
public String getDepartment() {
return department;
}
public void setDepartment(String department) {
this.department = department;
}
public String getYear() {
return year;
}
public void setYear(String year) {
this.year = year;
}
public String getFacultyId() {
return facultyId;
}
public void setFacultyId(String facultyId) {
this.facultyId = facultyId;
}
}
这是我的问题。我想在valueEventListener之外使用'addFaculty'或部门和年份变量。我知道很多人问与此有关的问题。我尝试了许多与此问题相关的解决方案,但没有成功。因此,如果您知道如何实现这一点,那将是很大的帮助。
创建用于访问变量的接口
interface CallbackFaculty {
void passFaculty(AddFaculty addFaculty);
}
然后您可以使用interface参数创建函数
private void getFaculty(CallbackFaculty callbackFaculty) {
databaseReference.orderByChild("email").equalTo(email).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
AddFaculty addFaculty = dataSnapshot1.getValue(AddFaculty.class);
department = addFaculty.getDepartment();
year = addFaculty.getYear();
callbackFaculty.passFaculty(addFaculty);
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
使用方法
getFaculty(new CallbackFaculty {
@Override
public void passFaculty(AddFaculty addFaculty) {
// here you have the access of addFaculty
// you can try logging addFaculty to check the value
}
});
希望它对您有帮助