使用orderbyvalue进行Firebase检索

时间:2017-07-13 21:41:19

标签: firebase

我试图检索像德里1这样的特定城市下的学生姓名。该代码在明确指定城市时起作用,但在城市是用户特定变量时不起作用。 JSON -

{
 "Schedule" : {
"Delhi 1 " : {
  "22" : {
    "6" : {
      "2017" : "9:00"
    }
  }
},
"Delhi 2 " : {
  "12" : {
    "6" : {
      "2017" : "5 pm"
    }
  }
},
"Delhi 3 " : {
  "1" : {
    "6" : {
      "2017" : "10 am"
    }
  },
  "10" : {
    "6" : {
      "2017" : "11 am"
    }
  }
}
 },
  "Students" : {
"Delhi_1" : {
  "s1345" : {
    "level" : "story",
    "name" : "s1345"
  },
  "s454" : {
    "level" : "paragraph",
    "name" : "s454"
  }
},
"Delhi_2" : {
  "abc12" : {
    "level" : "story",
    "name" : "abc12"
  },
  "bh45" : {
    "level" : "paragraph",
    "name" : "bh45"
  }
},
"Delhi_3" : {
  "ca12" : {
    "level" : "story",
    "name" : "ca12"
  },
  "cv23" : {
    "level" : "book",
    "name" : "cv23"
  }
},
"Delhi_4" : {
  "bv43" : {
    "level" : "story",
    "name" : "bv43"
  },
  "gf43" : {
    "level" : "story",
    "name" : "cf43"
  }
}
 },
"Volunteers" : {
"Delhi 1 " : {
  "abcd4" : {
    "attendance" : 0,
    "center" : "Delhi 1 ",
    "email" : "a@mail.com",
    "phone" : "45878704",
    "v_name" : "abcd4"
  },
  "df3" : {
    "attendance" : 0,
    "center" : "Delhi 1 ",
    "email" : "d@mail.com",
    "phone" : "58564543",
    "v_name" : "df3"
  }
},
 "Delhi 2 " : {
  "df4" : {
    "attendance" : 0,
    "center" : "Delhi 2 ",
    "email" : "d#mail.com",
    "phone" : "48745421212",
    "v_name" : "df4"
  }
},
"vabc1" : {
  "attendance" : 0,
  "center" : "Delhi 1 ",
  "email" : "s@mail.com",
  "phone" : "3799623472",
  "v_name" : "vabc1"
}
}
}


  Code-
  myRef=database.child(center);
  myRef.orderByValue().addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
     for(DataSnapshot child: dataSnapshot.getChildren()) {
    for(DataSnapshot child2: child.getChildren()) {
    Stringvalue=child.child("name").getValue().toString();                    
    value.setName(dataSnapshot.child("name").getValue().toString());
    System.out.println("Values" + value);
    }
   }
  }

0 个答案:

没有答案