我有一个注册活动，根据用户选中的复选框，对服务器进行异步调用以获取与所选字段相关的技能。我正在使用改造。我已经定义了一个SQLQuery类，其构造函数采用String参数。现在的问题是，当我使用String参数调用构造函数时，它显示错误Array type expected found java.lang.String。请有人帮我解决这个问题。
先谢谢，这是我的java文件
package com.example.vishal.internshipseekerapp;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.Toast;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class StudentRegistration extends AppCompatActivity implements View.OnClickListener {
private final int numFields = 13;
boolean[] checkField = new boolean[13];
String[] field = {"computer vision", "content writing", "data mining", "electrical/electronics", "game development", "image processing", "marketing", "mechanical engineering", "mobile app dev", "programming", "software dev", "web dev"};
Set<Skill> skill = new HashSet<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_student_registration);
ActionBar ab = getSupportActionBar();
ab.setDisplayHomeAsUpEnabled(true);
// register onclick listener for all checkboxes
( findViewById(R.id.field0)).setOnClickListener(this);
( findViewById(R.id.field1)).setOnClickListener(this);
( findViewById(R.id.field2)).setOnClickListener(this);
( findViewById(R.id.field3)).setOnClickListener(this);
( findViewById(R.id.field4)).setOnClickListener(this);
( findViewById(R.id.field5)).setOnClickListener(this);
( findViewById(R.id.field6)).setOnClickListener(this);
( findViewById(R.id.field7)).setOnClickListener(this);
( findViewById(R.id.field8)).setOnClickListener(this);
( findViewById(R.id.field9)).setOnClickListener(this);
( findViewById(R.id.field10)).setOnClickListener(this);
( findViewById(R.id.field11)).setOnClickListener(this);
//( findViewById(R.id.field12)).setOnClickListener(this);
// register onclick listener for DONE button
Button done = (Button) findViewById(R.id.field_select_done);
done.setOnClickListener(this);
}
public void onClick(View v){
switch(v.getId()){
case R.id.field0:
if(((CheckBox) v).isChecked())
checkField[0] = true;
case R.id.field1:
if(((CheckBox) v).isChecked())
checkField[1] = true;
case R.id.field2:
if(((CheckBox) v).isChecked())
checkField[2] = true;
case R.id.field3:
if(((CheckBox) v).isChecked())
checkField[3] = true;
case R.id.field4:
if(((CheckBox) v).isChecked())
checkField[4] = true;
case R.id.field5:
if(((CheckBox) v).isChecked())
checkField[5] = true;
case R.id.field6:
if(((CheckBox) v).isChecked())
checkField[6] = true;
case R.id.field7:
if(((CheckBox) v).isChecked())
checkField[7] = true;
case R.id.field8:
if(((CheckBox) v).isChecked())
checkField[8] = true;
case R.id.field9:
if(((CheckBox) v).isChecked())
checkField[9] = true;
case R.id.field10:
if(((CheckBox) v).isChecked())
checkField[10] = true;
case R.id.field11:
if(((CheckBox) v).isChecked())
checkField[11] = true;
case R.id.field_select_done:
displayRelevantSkills();
}
}
private void displayRelevantSkills() {
String field = "field";
String checkBoxName;
final String SKILL_FIELD_URL = "https://data.outfight74.hasura-app.io/";
// OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
// set request options for all requests
Retrofit.Builder builder =
new Retrofit.Builder()
.baseUrl(SKILL_FIELD_URL)
.addConverterFactory(
GsonConverterFactory.create()
);
// create retrofit adapter
Retrofit retrofit =
builder
/*.client(
httpClient.build()
)*/
.build();
// create retrofit REST client
getRelevantSkills skillClient = retrofit.create(getRelevantSkills.class);
// for each checkbox do
for(int i = 0; i < numFields; i++) {
// if checkbox is ticked
if(checkField[i]) {
// fetch relevant skills from server
SQLQuery skillQuery = new SQLQuery(field[i]);
Call<List<Skill>> call =
skillClient.relevantSkills(skillQuery);
// Execute the call asynchronously. Get a positive or negative callback.
call.enqueue(new Callback<List<Skill>>() {
@Override
public void onResponse(Call<List<Skill>> call, Response<List<Skill>> response) {
// The network call was a success and we got a response
// add to skills HashSet
skill.addAll(response.body());
Toast.makeText(getApplicationContext(), "Success", Toast.LENGTH_SHORT).show();
}
@Override
public void onFailure(Call<List<Skill>> call, Throwable t) {
// the network call was a failure
// TODO: handle error
Toast.makeText(getApplicationContext(), "Error", Toast.LENGTH_SHORT).show();
}
});
}
}
// display a drop down menu having all elements of HashSet
for(Skill s : skill)
{
CheckBox skillItem = new CheckBox(getApplicationContext());
skillItem.setText(s.getSkill());
}
}
}
这是getRelevantSkills.java file
package com.example.vishal.internshipseekerapp;
import java.util.List;
import retrofit2.Call;
import retrofit2.http.Body;
import retrofit2.http.POST;
class Where{
// this will be given by the user
private String skill;
public Where(String skill) {
this.skill = skill;
}
}
class Args{
final String table = "skill_field_relation";
final String[] columns = {"skill"};
private Where where;
public Args(String field) {
where = new Where(field);
}
}
class SQLQuery{
final String type = "select";
private Args args;
public SQLQuery(java.lang.String field) {
args = new Args(field);
}
}
class Skill{
private String skill;
public String getSkill() {
return skill;
}
public Skill(String skill) {
this.skill = skill;
}
}
public interface getRelevantSkills {
@POST("/v1/query")
Call<List<Skill>> relevantSkills(
@Body SQLQuery fetchSkills
);
}
答案 0 :(得分：2)
您正尝试将field[i]传递给SQLQuery构造函数，但field是String，而不是数组。您应该改为field。
编辑：
private void displayRelevantSkills() {
String field = "field";
...
SQLQuery skillQuery = new SQLQuery(field[i]);
...
}
您有一个类型为field的本地String变量，它隐藏了同名的实例变量（其类型为String[]）。
如果您打算使用实例变量（String[] field = {...};），您应该写：
SQLQuery skillQuery = new SQLQuery(this.field[i]);