java - 如何在 Firebase 实时数据库中保存生成的唯一 ID

Question

大家好，

我期待在 Firebase 实时数据库中保存使用推送方法保存信息时生成的唯一 ID。

下面是我的代码

String bookid = dbreference.child("books").child(condition).push().getKey();

                Toast.makeText(getApplicationContext(), "Your question will be uploaded shortly !", Toast.LENGTH_SHORT).show();
                b = new Books(btitle, bauthor, bdesc, condition, sellername, selleremail, sellermobile,  selleruniversity, bprice,bookid);


                dbreference.child("books").child(condition).child(bookid).setValue(b);

它存储来自textview的所有信息，但在bookid中它显示为空，我想存储push key“-LVx3qNb1HCxYKRE5cFl”

我的图书类(class)是

public class Books {
public String bname;
public String bauthor;
public String bdesc;
public String sellername;
public String selleremail;
public String sellermobile;
public String category;
public String selleruniversity;
public String bcondition;
public double price;
public String pics;
 public String bookid;
//  public Uri uri;

public Books(String bname, String bauthor, String bdesc, String bcondition, String sellername, String selleremail, String sellermobile,  String selleruniversity, double price, String bookid) {
    this.bname = bname;
    this.bauthor = bauthor;
    this.bdesc = bdesc;
    this.sellername = sellername;
    this.selleremail = selleremail;
    this.sellermobile = sellermobile;
    this.category = category;
    this.selleruniversity = selleruniversity;
    this.bcondition = bcondition;
    this.price = price;
    this.pics="";
     this.bookid="";
    //   this.uri = uri;
}

public Books(){}
public String getBname() {
    return bname;
}
public String getBauthor() {
    return bauthor;
}
public String getBdesc() {
    return bdesc;
}
public String getSellername() {
    return sellername;
}
public String getSelleremail() {
    return selleremail;
}
public String getSellermobile() { return sellermobile;}
public String getCategory() {
    return category;
}
public String getSelleruniversity() {
    return selleruniversity;
}
public String getCondition() { return bcondition;}
public Double getPrice() {
    return price;
}
public String getBookid() {
    return bookid;
}
public String getPics() {
    return pics;
}
public void setPics(String pics) {
    this.pics = pics;
}

}

Answer 1

您的数据库中有 "" ，因为这是您在构造函数中实例化 bookid 字段的方式。要解决此问题，请在您的 Books 类中更改以下代码行:

this.bookid="";

至

this.bookid = bookid;