我目前正在使用Retrofit 2来检索JSON对象数组。与我的URL的连接是成功的，但是由于列表始终以null返回，因此数据从未成功检索。我不确定为什么会这样。任何帮助将不胜感激，谢谢。
JSON数据：
{
"result":{
"data":[
{
"image":"test1",
"text":"text1",
"time":1,
"key":"pm-02"
},
{
"image":"test2",
"text":"test2",
"time":2,
"key":"pm-03"
},
{
"image":"test3",
"text":"test3",
"time":3,
"key":"pm-01"
},
{
"image":"test4",
"text":"test4",
"time":4,
"key":"pm-04"
},
{
"image":"test5",
"text":"test5",
"time":5,
"key":"pm-07"
}
],
"nextKey":6
}
}
Api界面：
public interface Api {
String BASE_URL = "URL";
@GET("PathtoUrlFunction")
Call<resultList>getResult(@Query("uid")
String myUID, @Query("amount") String
amount);
}
resultList.java
public class resultList {
private static final String TAG = "RESULT LIST";
@SerializedName("data")
@Expose
private List<MessageReference> data;
public List<MessageReference> getResult() {
Log.d(TAG, " STACK OVERFLOW - IN MY RESULT LIST CLASS" + data);
return data;
}
public void setResult(List<MessageReference> temp) { this.data = temp;}
}
MessageReference.java
public class MessageReference {
private String image;
private String text;
private int time;
private String key;
public MessageReference(String image, String text, int time, String key) {
this.text = text;
this.image = image;
this.time = time;
this.key = key;
}
public MessageReference() { }
public String getImage() { return image;
}
public String getText() { return text; }
public int getTime() { return time; }
public String getKey() { return key; }
public void setImage(String image) { this.image = image; }
public void setText(String text) { this.text = text; }
public void setTime(int time) { this.time = time; }
public void setKey(String key) { this.key = key; }
}
SocialMediaTab.Java（在哪里进行呼叫）
Retrofit retrofit = new Retrofit.Builder().baseUrl(Api.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
...
Api api = retrofit.create(Api.class);
Log.d(TAG, "STACK OVERFLOW - API CREATE " + api);
// get result takes in 2 paramters - uid of the user (to retrieve their data), and the amount of objects desired in the returned json array, in this case - 5
Call<resultList> call = api.getResult(loggedinUID, "5");
Log.d(TAG, "STACK OVERFLOW - CALL CREATE " + call);
call.enqueue(new Callback<resultList>() {
@Override
public void onResponse(Call<resultList> call, Response<resultList> response) {
Log.d(TAG, " ON RESPONSE " + call);
resultList result = response.body();
Log.i(TAG, " STACK OVERFLOW - MY CALL" + result.getResult());
}
@Override
public void onFailure(Call <resultList> call, Throwable t) {
Log.i(TAG, "FAILURE " );
t.printStackTrace();
}
});
}
LogCat（在以上文件中）
D/Social Media Tab: STACK OVERFLOW - API CREATE retrofit2.Retrofit$1@131b108
D/Social Media Tab: STACK OVERFLOW - CALL CREATE retrofit2.DefaultCallAdapterFactory$ExecutorCallbackCall@d24c09b
D/RESULT LIST: STACK OVERFLOW - IN MY RESULT LIST CLASSnull
I/Social Media Tab: STACK OVERFLOW - MY CALLnull
答案 0 :(得分：0)
我认为它们是您的resultList类中的问题。您正在使用“数据”，而不是在模型类中调用“结果”。
预期的列表结果不是直接数据。
您的模型类应该是这样的：
结果类
public class Result {
@SerializedName("data") @Expose private List<Datum> data = null; @SerializedName("nextKey") @Expose private Integer nextKey;
public List<Datum> getData() { return data; }
public void setData(List<Datum> data) { this.data = data; }
public Integer getNextKey() { return nextKey; }
public void setNextKey(Integer nextKey) { this.nextKey = nextKey; }
}
基准类别：
public class Datum {
@SerializedName("image")
@Expose
private String image;
@SerializedName("text")
@Expose
private String text;
@SerializedName("time")
@Expose
private Integer time;
@SerializedName("key")
@Expose
private String key;
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public Integer getTime() {
return time;
}
public void setTime(Integer time) {
this.time = time;
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
}
示例类：
public class Example {
@SerializedName("result")
@Expose
private Result result;
public Result getResult() {
return result;
}
public void setResult(Result result) {
this.result = result;
}
}
您的ApiInterface应该是这样的：
public interface Api {
String BASE_URL = "URL";
@GET("PathtoUrlFunction")
Call<Result>getResult(@Query("uid")
String myUID, @Query("amount") String
amount);
}
希望这会有所帮助。让我知道他们是否对此有任何疑问！
编码愉快！
答案 1 :(得分：0)
我认为您的回应pojo课堂上有问题。 pojo类应该是一个带有jsonarray的对象，下面是一个粗糙的代码。
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#define MAX_CONNECTIONS 10
#define BUF_SIZE 2000
#define STREQU(a,b) (strcmp(a, b) == 0)
void init_local_sockaddr_in(struct sockaddr_in *sock, int portnum) {
sock->sin_family = AF_INET;
sock->sin_addr.s_addr = inet_addr("127.0.0.1");
sock->sin_port = htons(portnum);
}
int main(int argc, char *argv[])
{
int listen_sockfd, input_sockfd, c, read_size, n;
struct sockaddr_in server, client;
char client_message[2000] = {0};
char bufferout[2000] = {0};
listen_sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (listen_sockfd == -1) {
printf("Could not create sockets");
}
puts("Socket created");
// Just for better debugging
int optval = 1;
setsockopt(listen_sockfd, SOL_SOCKET, SO_REUSEADDR, (const void *)&optval , sizeof(int));
init_local_sockaddr_in(&server, 10025);
n = bind(listen_sockfd, (struct sockaddr*) &server, sizeof(server));
if (n < 0) {
perror("bind failed. Error");
return 1;
}
listen(listen_sockfd , MAX_CONNECTIONS);
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while(1) {
input_sockfd = accept(listen_sockfd, (struct sockaddr*) &client, (socklen_t*) &c);
if (input_sockfd < 0) {
perror("accept failed");
return 1;
}
puts("Connection accepted");
sprintf(bufferout, "250 mail.domain.com says hello\r\n"); // I tried different replies here, including 220
send(input_sockfd, bufferout, strlen(bufferout), 0);
puts(bufferout);
int keep_running = 1;
while (keep_running) {
n = read(listen_sockfd, client_message, sizeof(client_message));
if (STREQU(client_message, ".") || n < 0) {
keep_running = 0;
break;
}
printf("Read %lu bytes: %s\n", strlen(client_message), client_message);
memset(client_message, 0, sizeof(client_message));
}
close(input_sockfd);
puts("Finished reading current message");
}
close(listen_sockfd);
return 0;
}