我正在使用改造库来获取检查登录凭据,我的包含响应的php文件如下
login.php

 ...
 if ($user["invalid credentials"] != "true"){
    $response["error"] = FALSE;
    $response["id"] = $user["credentials"]["admin_id"];
    $response["username"] = $user["credentials"]["username"];
    $response["password"] = $user["credentials"]["password"];
    $response["email"] = $user["credentials"]["email"];
    echo json_encode($response);
  }
else {
    $response["error"] = TRUE;
    $response["error_msg"] = "Τα στοιχεία εισόδου είναι λάθος. Παρακαλώ ξαναπροσπάθησε.";
    echo json_encode($response);
}
...


POJO课

 public class User {
      private int id;
      private String error, error_msg, username, email, password;

public String getError(){
    return this.error;
}

public String getError_msg(){
    return this.error_msg;
}

public int getId(){
    return this.id;
}

public String getUsername(){
    return this.username;
}

public String getPassword(){
    return this.password;
}

public String getEmail(){
    return this.email;
}
 }


我的api服务接口,其中validateUser方法具有用户输入的用户名和密码
Api服务

   public interface ApiService {

@FormUrlEncoded
@POST("/login/login.php/")
Call<User> validateUser(@Field("username") String username, @Field("password") String password);
 }


和我创建Retrofit对象的checkLogin方法

private void checkLogin(String username, String password){

    Retrofit retrofit = new Retrofit.Builder()
                        .baseUrl(AppConfig.BASE_URL)
                        .addConverterFactory(GsonConverterFactory.create())
                        .build();

    ApiService apiService = retrofit.create(ApiService.class);
    Call<User> call = apiService.validateUser(username, password);
    call.enqueue(new Callback<User>() {
        @Override
        public void onResponse(retrofit.Response<User> response, Retrofit retrofit) {
                String email = response.body().getEmail();
                Log.d(debugTag, "email: " + email);
        }

        @Override
        public void onFailure(Throwable t) {

        }
    });
 }


当我尝试获取用户的电子邮件时(如果凭据有效),将发生错误。我收到一个空指针异常...我的POJO类有问题吗?


  致命异常:主要
        11-09 22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
        E / AndroidRuntime:进程:com.votingsystem.tsiro.votingsystem,PID:21558
        11-09 22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
        E / AndroidRuntime:java.lang.NullPointerException
        11-09 22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
        E / AndroidRuntime:at com.votingsystem.tsiro.fragments.LoginFragment $ 4.onResponse(LoginFragment.java:175)
         11-09 22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
          E / AndroidRuntime:在retrofit.ExecutorCallAdapterFactory $ ExecutorCallback $ 1.run(ExecutorCallAdapterFactory.java:86)
  11-09 22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
  E / AndroidRuntime:位于
  android.os.Handler.handleCallback(Handler.java:733)11-09 22:51:06.152
  21558-21558 / com.votingsystem.tsiro.votingsystem E / AndroidRuntime:
  在android.os.Handler.dispatchMessage(Handler.java:95)11-09
  22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
  E / AndroidRuntime:位于android.os.Looper.loop(Looper.java:136)11-09
  22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
  E / AndroidRuntime:位于
  android.app.ActivityThread.main(ActivityThread.java:5146)11-09
  22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
  E / AndroidRuntime:位于java.lang.reflect.Method.invokeNative(本机
  方法)11-09 22:51:06.152
  21558-21558 / com.votingsystem.tsiro.votingsystem E / AndroidRuntime:
  在java.lang.reflect.Method.invoke(Method.java:515)11-09 22:51:06.152
  21558-21558 / com.votingsystem.tsiro.votingsystem E / AndroidRuntime:
  在
  com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:732)
  11-09 22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
  E / AndroidRuntime:位于
  com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566)11-09
  22:51:06.152 21558-21558 / com.votingsystem.tsiro.votingsystem
  E / AndroidRuntime:位于dalvik.system.NativeStart.main(本机方法)

最佳答案

最终,在深入研究Retrofit 2.0.0文档之后,我设法解决了该问题。根据本指南https://futurestud.io/blog/retrofit-2-upgrade-guide-from-1-9/,HttpUrl.resolve()方法创建类似于的链接。之后,我从覆盖BASE_URL最后一部分的部分url @POST(“ / login / login.php /”)中删除了开头的/,并将其添加到BASE_URL中,一切正常。

10-08 18:20