Java 从json文件填充文本视图无效
嗨,我是android studio的新手 我有一棵JSON树Java 从json文件填充文本视图无效,java,android,json,android-edittext,Java,Android,Json,Android Edittext,嗨,我是android studio的新手 我有一棵JSON树 [ { "id": 1, "name": "jhon", "salary": 1500 }, { "id": 2, "name": "sal", "salary": 1700 }, { "id": 3, "name": "bob", "salary": 2500 }, { "id": 4, "name": "ned",
[
{
"id": 1,
"name": "jhon",
"salary": 1500
},
{
"id": 2,
"name": "sal",
"salary": 1700
},
{
"id": 3,
"name": "bob",
"salary": 2500
},
{
"id": 4,
"name": "ned",
"salary": 1800
},
{
"id": 5,
"name": "mike",
"salary": 1300
}
]
我的项目分为三个部分。
首先,用户可以在EditText
小部件中输入一个Int,以显示对应于id的名称的toast。
第三个是最小-最大搜索,用户输入两个整数
,搜索它们之间的所有工资。
但是第二部分是我遇到问题的地方,我有一个员工姓名的微调器。用户应该选择一个姓名,然后单击btnSearchName
按钮,在文本视图中显示相应用户的信息(id姓名和工资)
,在按姓名搜索.xml
,但是,当我单击搜索按钮时,我被带到XML文件,但是employeeInfo
文本视图是空的,没有错误消息或崩溃,只是一个空的活动,我无法找到它
这是MainActivity.java
package com.hfad.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText editId = findViewById(R.id.editId);
final EditText editMin = findViewById(R.id.editMin);
final EditText editMax = findViewById(R.id.editMax);
final Spinner spName = findViewById(R.id.spinnerName);
final String url = "https://api.myjson.com/bins/dxnri";
final ArrayList<String> employeeName = new ArrayList<>();
JsonArrayRequest jsonSpinner = new JsonArrayRequest(Request.Method.GET, url,
null,new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
try {
for (int i = 0; i < response.length(); i++) {
JSONObject st = response.getJSONObject(i);
String name = st.getString("name");
employeeName.add(name);
}
spName.setAdapter(new ArrayAdapter<String>(MainActivity.this,
android.R.layout.simple_spinner_dropdown_item, employeeName));
} catch (JSONException e) { e.printStackTrace(); }
} }, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.i("error", error.toString());
}
});
MySingleton.getMInstance(MainActivity.this).addToRequestQueue(jsonSpinner);
Button btnSearchId = findViewById(R.id.btnSearchId);
btnSearchId.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
JsonArrayRequest jsonId = new JsonArrayRequest(Request.Method.GET, url,
null,new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
try {
boolean found = false;
for (int i = 0; i < response.length(); i++) {
String name;
JSONObject st = response.getJSONObject(i);
int id = st.getInt("id");
if(id == Integer.parseInt(editId.getText().toString())) {
name = st.getString("name");
Toast.makeText(getApplicationContext(),
"The employee's name is " + name,
Toast.LENGTH_LONG).show();
found = true;
break;
}
}
if(!found)
Toast.makeText(getApplicationContext(),"Invalid Id",
Toast.LENGTH_LONG).show();
} catch (JSONException e) { e.printStackTrace(); }
} }, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.i("error", error.toString());
}
});
MySingleton.getMInstance(MainActivity.this).addToRequestQueue(jsonId);
}
});
Button btnSearchName = findViewById(R.id.btnSearchName);
btnSearchName.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, SearchByName.class);
intent.putExtra("EmployeeName", spName.getSelectedItem().toString());
startActivity(intent);
}
});
Button btnSearchSalary = findViewById(R.id.btnSearchSalary);
btnSearchSalary.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, SearchBysalary.class);
intent.putExtra("salaryMin", editMin.getText().toString());
intent.putExtra("salaryMax", editMax.getText().toString());
startActivity(intent);
}
});
}
}
package com.hfad.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class SearchByName extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search_by_name);
final TextView employeeInfo = findViewById(R.id.employeeInfo);
final String employeeName = getIntent().getStringExtra("name");
final Spinner spName = findViewById(R.id.spinnerName);
String url = "https://api.myjson.com/bins/dxnri";
JsonArrayRequest jsonName = new JsonArrayRequest(Request.Method.GET, url,
null,new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
try {
for (int i = 0; i < response.length(); i++) {
JSONObject st = response.getJSONObject(i);
int id = st.getInt("id");
String name = st.getString("name");
int salary = st.getInt("salary");
if(name.equals(employeeName)) {
employeeInfo.setText("Id: " + id + "\n\nName: " + name + "\n\nSalary: " + salary);
break;
// "Id: " + id + "\n\nName: " + name + "\n\nSalary: " + salary
}
}
} catch (JSONException e) { e.printStackTrace(); }
} }, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.i("error", error.toString());
}
});
MySingleton.getMInstance(SearchByName.this).addToRequestQueue(jsonName);
}
}
您可能会遇到一个问题,即您试图启动与已启动的活动相同的活动。这是行不通的<如果活动正在运行,则不会再次调用代码>onCreated
您应该执行以下操作之一:
- 在
MainActivity
方法onNewIntent
中验证,并在此处执行所有JSON逻辑
- 忘记意图,使用
AsyncTask
(已弃用)或其他异步模式来完成任务
在MainActivity.java
中,您添加了一个额外的目的:
intent.putExtra("EmployeeName", spName.getSelectedItem().toString());
但是在SerachByName.java
中,您可以这样检索它:
final String employeeName = getIntent().getStringExtra("name");
键
不同,请将SearchByName.java中的名称
更改为员工姓名
此外,对于你来说,最酷的事情就是学习针对API请求的改型和rxJava。它成功了,这不是我第一次因为一个简单的错误而挠头,但现在它成功了,世界又变好了,谢谢。
intent.putExtra("EmployeeName", spName.getSelectedItem().toString());
final String employeeName = getIntent().getStringExtra("name");