Post 值使用改造

Question

我目前是 android 的新手。我正在使用此站点进行练习：http://dummy.restapiexample.com/，我正在尝试使用 post 请求这是我正在使用的代码，我使用了 jsonschema2pojo 并创建了两个类，这让我很困惑，为什么我们需要两个类？以及如何使用它们？代码没有崩溃。但是，当我在 toast 中显示值时，我得到 null。

JsonPlaceholer.java

public interface JsonPlaceHolderApi {

@FormUrlEncoded
@POST("create")
Call<Post> createPost(@FieldMap Map<String, String> fields);
}

Mainactivity.java

public class MainActivity extends AppCompatActivity {

TextView textViewResult;

private JsonPlaceHolderApi jsonPlaceHolderApi;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    textViewResult = findViewById(R.id.text_view_result);

    Retrofit retrofit = new Retrofit.Builder()
           // .baseUrl("https://jsonplaceholder.typicode.com/")
            .baseUrl("http://dummy.restapiexample.com/api/v1/")
            .addConverterFactory(GsonConverterFactory.create())
            .build();

    jsonPlaceHolderApi = retrofit.create(JsonPlaceHolderApi.class);

    createPost();
  }

private void createPost() {

    //Post post = new Post(23, "New Title", "New Text");

    Map<String, String> fields = new HashMap<>();
    fields.put("name", "NewName");
    fields.put("salary", "123");
    fields.put("age","12");

    Call<Post> call = jsonPlaceHolderApi.createPost(fields);

    call.enqueue(new Callback<Post>() {
        @Override
        public void onResponse(Call<Post> call, Response<Post> response) {

            if (!response.isSuccessful()) {
                textViewResult.setText("Code: " + response.code());
                return;
            }

            Post postResponse = response.body();

            String content = "";
            content += "Code: " + response.code() + "\n";
            content += "ID: " + postResponse.getId() + "\n";

            content += "Name : " + postResponse.getName() + "\n";
            content += "Salary : " + postResponse.getSalary() + "\n";
            content += "Age :" + postResponse.getAge() + "\n\n";

           // textViewResult2.setText(content);
            Toast.makeText(MainActivity.this, "Ans::"+content, Toast.LENGTH_LONG).show();
        }

        @Override
        public void onFailure(Call<Post> call, Throwable t) {

            //textViewResult.setText(t.getMessage());
            Toast.makeText(MainActivity.this, "Failed "+t.getMessage(), Toast.LENGTH_LONG).show();
        }
    });
}
 }

Post.java

public class Post {

@SerializedName("name")
@Expose
private String name;
@SerializedName("salary")
@Expose
private String salary;
@SerializedName("age")
@Expose
private String age;
@SerializedName("id")
@Expose
private Integer id;

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getSalary() {
    return salary;
}

public void setSalary(String salary) {
    this.salary = salary;
}

public String getAge() {
    return age;
}

public void setAge(String age) {
    this.age = age;
}

public Integer getId() {
    return id;
}

public void setId(Integer id) {
    this.id = id;
}


}

PostR.java

public class PostR {

@SerializedName("status")
@Expose
private String status;
@SerializedName("data")
@Expose
private Post data;

public String getStatus() {
    return status;
}

public void setStatus(String status) {
    this.status = status;
}

public Post getData() {
    return data;
}

public void setData(Post data) {
    this.data = data;
}

}

Answer 1

2 classes 用于 DTO（数据传输对象），映射来自 API eith Java 对象的响应 将响应数据映射到 Java 个对象。

Replace your code with below code, it should work:

Call<PostR> call = jsonPlaceHolderApi.createPost(fields);
    call.enqueue(new Callback<PostR>() {
        @Override
        public void onResponse(Call<PostR> call, Response<PostR> response) {    
            if (!response.isSuccessful()) {
                textViewResult.setText("Code: " + response.code());
                return;
            }    
            PostR postRResponse = response.body();
            Post postResponse = postRResponse.getData();
            if(postResponse!=null) {
                String content = "";
                content += "Code: " + response.code() + "\n";
                content += "ID: " + postResponse.getId() + "\n";    
                content += "Name : " + postResponse.getName() + "\n";
                content += "Salary : " + postResponse.getSalary() + "\n";
                content += "Age :" + postResponse.getAge() + "\n\n";
            }
           // textViewResult2.setText(content);
            Toast.makeText(MainActivity.this, "Ans::"+content, Toast.LENGTH_LONG).show();
        }

        @Override
        public void onFailure(Call<PostR> call, Throwable t) {    
            //textViewResult.setText(t.getMessage());
            Toast.makeText(MainActivity.this, "Failed "+t.getMessage(), Toast.LENGTH_LONG).show();
        }

P.S - General Process you can follow to test API:

使用 Postman.
在日志中打印 response.code() 和 response.body()。
检查响应的结构（keys/params）是否与PostR.java相同
检查 response.body() 的结构 (keys/params) 是否与 Post.java class.
如果以上所有都按预期工作，您的 Toast 应该打印正确的值。

Answer 2

好的，快速看一下，您的 PostR.java 是您从回调中收到的响应的 POJO class，Post.java 是 POJO class 是什么在 data 中返回所以在你的 MainActivity.java 中你需要用 Call<PostR> 替换所有 Call<Post> 因为 PostR.java 是你用 Post 对象得到的响应它。

尝试看看是否有帮助。

编辑： 别忘了用 Callback<PostR> 和 Response<PostR> 替换 Callback<Post> 和 Response<Post>

Post 值使用改造

Post values using retrofit

java

android

retrofit2

development-environment