如何直接从Firebase Cloud Firestore 检索数据到自定义的JAVA对象中。

huangapple
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英文:

How to Retrieve Data directly from the Firebase Cloud Firestore into a CUSTOM JAVA OBJECT

问题

  1. ![图片描述](链接)
  3. 我无法插入图片，您可以访问上面的链接或阅读下面的描述。
  4. 这是Firestore中的文档内容 -

个人资料

出生日期 23032001
年龄 19
会员 "GOLD"
姓名 "Saheel"
训练师姓名 "trainer1"

  1. 我通过Firebase控制台手动添加了数据。现在我想将数据检索到应用程序中创建的自定义Java对象中。
  2. 此对象专为该文档定制。
  3. 测试类 -
  5. ```java
  6. package com.example.firebase;
  8. public class test {
  9.     private String name;
  10.     private int DOB;
  11.     private int age;
  12.     private String membership;
  13.     private String trainer_name;
  15.     public test(String name, int DOB, int age, String membership, String trainer_name) {
  16.         this.name = name;
  17.         this.DOB = DOB;
  18.         this.age = age;
  19.         this.membership = membership;
  20.         this.trainer_name = trainer_name;
  21.     }
  23.     public test(){
  24.         //无参构造函数
  25.     }
  27.     // 省略了getter和setter方法
  28. }

从数据库请求数据的代码 -

  1. //自定义对象
  3. db.collection("users").document("Saheel").collection("profile")
  4.         .document("profile").get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
  5.     @Override
  6.     public void onSuccess(DocumentSnapshot documentSnapshot) {
  7.         test test = documentSnapshot.toObject(com.example.firebase.test.class);
  8.         name_t.setText(test.getName());
  9.         age_t.setText(String.valueOf(test.getAge()));  // 将整数转换为字符串
  10.         dob_t.setText(String.valueOf(test.getDOB()));  // 将整数转换为字符串
  11.         membership_t.setText(test.getMembership());
  12.         trainer_t.setText(test.getTrainer_name());
  13.     }
  14. });

应用程序会立即崩溃，并且Logcat显示以下错误 -

  1. 2020-10-07 20:50:30.366 9016-9016/com.example.firebase E/AndroidRuntime: FATAL EXCEPTION: main
  2.     Process: com.example.firebase, PID: 9016
  3.     android.content.res.Resources$NotFoundException: String resource ID #0x13
  4.         at android.content.res.Resources.getText(Resources.java:444)
  5.         at android.widget.TextView.setText(TextView.java:6412)
  6.         at com.example.firebase.MainActivity$1.onSuccess(MainActivity.java:81)
  7.         at com.example.firebase.MainActivity$1.onSuccess(MainActivity.java:76)
  8.         at com.google.android.gms.tasks.zzn.run(Unknown Source:4)
  9.         at android.os.Handler.handleCallback(Handler.java:938)
  10.         at android.os.Handler.dispatchMessage(Handler.java:99)
  11.         at android.os.Looper.loop(Looper.java:223)
  12.         at android.app.ActivityThread.main(ActivityThread.java:7656)
  13.         at java.lang.reflect.Method.invoke(Native Method)
  14.         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
  15.         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

我是否遵循了正确的流程？在Firestore中是否可能执行此操作？

  2. <details>
  3. <summary>英文:</summary>
  5. [![enter image description here][1]][1]
  7. I cant insert the image, you can visit the link above or read the description below.
  8. This is how the Document in the Firestore is present -

Profile

DOB 23032001
age 19
membership "GOLD"
name "Saheel"
trainer_name "trainer1"

  1. I added the data manually through the Firebase console. Now I want to retrieve the data into an Custom Java Object which i have created in the application.
  2. This object is tailor made for the document.
  3. Test class -
  5. ```java
  6. package com.example.firebase;
  8. public class test {
  9.     private String name;
  10.     private int DOB;
  11.     private int age;
  12.     private String membership;
  13.     private String trainer_name;
  15.     public test(String name, int DOB, int age, String membership, String trainer_name) {
  16.         this.name = name;
  17.         this.DOB = DOB;
  18.         this.age = age;
  19.         this.membership = membership;
  20.         this.trainer_name = trainer_name;
  21.     }
  23.     public test(){
  24.         //no-argument constructor
  25.     }
  27.     public String getName() {
  28.         return name;
  29.     }
  31.     public void setName(String name) {
  32.         this.name = name;
  33.     }
  35.     public int getDOB() {
  36.         return DOB;
  37.     }
  39.     public void setDOB(int DOB) {
  40.         this.DOB = DOB;
  41.     }
  43.     public int getAge() {
  44.         return age;
  45.     }
  47.     public void setAge(int age) {
  48.         this.age = age;
  49.     }
  51.     public String getMembership() {
  52.         return membership;
  53.     }
  55.     public void setMembership(String membership) {
  56.         this.membership = membership;
  57.     }
  59.     public String getTrainer_name() {
  60.         return trainer_name;
  61.     }
  63.     public void setTrainer_name(String trainer_name) {
  64.         this.trainer_name = trainer_name;
  65.     }
  66. }

The code which requests the data from the database -

  1. //CUSTOM OBJECTS
  3.         db.collection(&quot;users&quot;).document(&quot;Saheel&quot;).collection(&quot;profile&quot;)
  4.                 .document(&quot;profile&quot;).get().addOnSuccessListener(new OnSuccessListener&lt;DocumentSnapshot&gt;() {
  5.             @Override
  6.             public void onSuccess(DocumentSnapshot documentSnapshot) {
  7.                 test test =documentSnapshot.toObject(com.example.firebase.test.class);
  8.                 name_t.setText(test.getName());
  9.                 age_t.setText(test.getAge());
  10.                 dob_t.setText(test.getDOB());
  11.                 membership_t.setText(test.getMembership());
  12.                 trainer_t.setText(test.getTrainer_name());
  13.             }
  14.         });

The Application crashes immediately and the logcat shows the below error -

  1. 2020-10-07 20:50:30.366 9016-9016/com.example.firebase E/AndroidRuntime: FATAL EXCEPTION: main
  2.     Process: com.example.firebase, PID: 9016
  3.     android.content.res.Resources$NotFoundException: String resource ID #0x13
  4.         at android.content.res.Resources.getText(Resources.java:444)
  5.         at android.widget.TextView.setText(TextView.java:6412)
  6.         at com.example.firebase.MainActivity$1.onSuccess(MainActivity.java:81)
  7.         at com.example.firebase.MainActivity$1.onSuccess(MainActivity.java:76)
  8.         at com.google.android.gms.tasks.zzn.run(Unknown Source:4)
  9.         at android.os.Handler.handleCallback(Handler.java:938)
  10.         at android.os.Handler.dispatchMessage(Handler.java:99)
  11.         at android.os.Looper.loop(Looper.java:223)
  12.         at android.app.ActivityThread.main(ActivityThread.java:7656)
  13.         at java.lang.reflect.Method.invoke(Native Method)
  14.         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
  15.         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Am I following the right procedure? Is it possible to do this Operation in Firestore?

答案1

得分: 1

由于text.getDOB()返回一个整数，此代码尝试将整数放入TextView中：

  1. dob_t.setText(test.getDOB());

当您使用整数调用setText时，Android会将该整数视为具有给定数字ID的字符串资源。由于Android找不到该字符串资源，因此会导致应用崩溃。

如果您需要在TextView中显示数字作为字符串，您需要首先将其转换为字符串：

  1. dob_t.setText(Integer.toString(test.getDOB()));
英文:

Since text.getDOB() returns an int, this code is trying to put an integer into a TextView:

  1. dob_t.setText(test.getDOB());

When you call setText with an integer, Android takes that integer to be a string resource with the given numeric ID. Since Android can't find that string resource, it crashes.

If you need to show a number as a string in a TextView, you will need to convert it to a string first:

  1. dob_t.setText(Integer.toString(test.getDOB()));

huangapple
  • 本文由 发表于 2020年10月7日 23:25:53
  • 转载请务必保留本文链接：https://go.coder-hub.com/64247277.html
  • android
  • firebase
  • google-cloud-firestore
  • java
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