当我发送请求下载它时,我遇到了Java Volley的问题,该错误给出错误的URL null null,我不明白为什么这样做。 我正在使用开放天气地图供json下载。 该代码会在on click方法中设置网址,然后调用下面的JSON下载器代码。
public String Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
上述LocationID的示例为2657832,以生成网址: api.openweathermap.org/data/2.5/forecast?id=2657832&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial 如果您将其输入到网络浏览器中,它将起作用
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, webAdress,
null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
String RESP = response.toString();
TEXT.setText("Response: " + RESP);
Log.d("TAG", "onResponse: " + webAdress);
Log.d("RESP", "onResponse: " + RESP);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
TEXT.setText("That didn't work!");
Log.d("TAG", "onErrorResponse: " + webAdress);
}
});
设置URL的点击方法
@Override
public void onClick(View v){
switch (v.getId()) {
case R.id.BTN_fav1:
LocationID = fave1S;
Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + LocationID + " " + webAdress);
break;
但是如果我将json请求中的URL设置为JOSN_WEB而不是webAdress,这是一个技巧,这是我们从课程工作中获得的url
public String JSON_WEB = "http://datapoint.metoffice.gov.uk/public/data/val/wxfcs/all/json/sitelist?key=0732c29d-95d4-41e3-9903-5a9244b3cd5b";
完整代码:
package com.example.ewan.coursework;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.nfc.Tag;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.MultiAutoCompleteTextView;
import android.widget.Spinner;
import android.widget.TextView;
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.JsonObjectRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONObject;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
enter code herepublic class MainActivity extends AppCompatActivity implements View.OnClickListener {
public static final String SHARED_PREFS = "SHARED_PREFS";
public static final String fave1 = "Fave1";
public static final String fave2 = "Fave2";
public static final String fave3 = "Fave3";
public static final String fave4 = "Fave4";
public static final String fave5 = "Fave5";
private String fave1S;
private String fave2S;
private String fave3S;
private String fave4S;
private String fave5S;
Button BTN_fav1;
Button BTN_fav2;
Button BTN_fav3;
Button BTN_fav4;
Button BTN_fav5;
public String LocationName;
public String LocationID;
public String JSON_WEB = "http://datapoint.metoffice.gov.uk/public/data/val/wxfcs/all/json/sitelist?key=0732c29d-95d4-41e3-9903-5a9244b3cd5b";
public String Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
public String webAdress;
public String[] location;
public String[] favourites;
public Spinner SP_location;
RequestQueue queue;
TextView TEXT;
AutoCompleteTextView ACTV;
Button BTN_search;
Button BTN_settings;
private static final String Key_Value = "value";
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString(Key_Value,String.valueOf(TEXT.getText()));
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
BTN_fav1 = findViewById(R.id.BTN_fav1);
BTN_fav2 = findViewById(R.id.BTN_fav2);
BTN_fav3 = findViewById(R.id.BTN_fav3);
BTN_fav4 = findViewById(R.id.BTN_fav4);
BTN_fav5 = findViewById(R.id.BTN_fav5);
BTN_fav1.setOnClickListener(this);
BTN_fav2.setOnClickListener(this);
BTN_fav3.setOnClickListener(this);
BTN_fav4.setOnClickListener(this);
BTN_fav5.setOnClickListener(this);
BTN_search = findViewById(R.id.BTN_search);
BTN_search.setOnClickListener(this);
BTN_settings = findViewById(R.id.BTN_settings);
BTN_settings.setOnClickListener(this);
TEXT = findViewById(R.id.TV_result_test);
Resources res = getResources();
location = res.getStringArray(R.array.locations);
ACTV = findViewById(R.id.ACTV_search);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_expandable_list_item_1,location);
ACTV.setAdapter(adapter);
queue = Volley.newRequestQueue(this);
if (savedInstanceState != null) {
TEXT.setText(savedInstanceState.getString(Key_Value));
}
loadData();
updateViews();
try{URL url = new URL(webAdress);} catch (MalformedURLException e) {
e.printStackTrace();
}
}
@Override
public void onClick(View v){
switch (v.getId()) {
case R.id.BTN_fav1:
LocationID = fave1S;
Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + LocationID + " " + webAdress);
break;
case R.id.BTN_fav2:
LocationID = fave2S;
Weather = "api.openweathermap.org/data/2.5/forecast?id=\" + LocationID + \"&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + webAdress);
break;
case R.id.BTN_fav3:
LocationID = fave3S;
Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + webAdress);
break;
case R.id.BTN_fav4:
LocationID = fave4S;
Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + webAdress);
break;
case R.id.BTN_fav5:
LocationID = fave5S;
Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + webAdress);
break;
case R.id.BTN_search:
LocationID = ACTV.getText().toString();
Weather = "api.openweathermap.org/data/2.5/forecast?id=" + LocationID + "&APPID=99b1346cd10b7389a4592e7f3123a412&units=imperial";
webAdress = Weather;
queue.add(jsonObjectRequest);
Log.d("TAG", "onClick: " + webAdress);
break;
case R.id.BTN_settings:
startActivity(new Intent(MainActivity.this,settings.class));
break;
}
}
StringRequest stringRequest = new StringRequest(Request.Method.GET, JSON_WEB,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Display the first 500 characters of the response string.
TEXT.setText("Response is: " + response.substring(0, 500));
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
TEXT.setText("That didn't work!");
}
});
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, webAdress,
null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
String RESP = response.toString();
TEXT.setText("Response: " + RESP);
Log.d("TAG", "onResponse: " + webAdress);
Log.d("RESP", "onResponse: " + RESP);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
TEXT.setText("That didn't work!");
Log.d("TAG", "onErrorResponse: " + webAdress);
}
});
public void loadData()
{
SharedPreferences sharedPreferences = getSharedPreferences(SHARED_PREFS, MODE_PRIVATE);
fave1S = sharedPreferences.getString(fave1, "Favorite not set");
fave2S = sharedPreferences.getString(fave2, "Favorite not set");
fave3S = sharedPreferences.getString(fave3, "Favorite not set");
fave4S = sharedPreferences.getString(fave4, "Favorite not set");
fave5S = sharedPreferences.getString(fave5, "Favorite not set");
Log.d("tag", "loadData: " + fave1 + " saved as " + fave1S);
}
public void updateViews()
{
BTN_fav1.setText(fave1S);
BTN_fav2.setText(fave2S);
BTN_fav3.setText(fave3S);
BTN_fav4.setText(fave4S);
BTN_fav5.setText(fave5S);
}
}
谢谢您的任何建议。依云
答案 0 :(得分:0)
final ThreadLocal<JsonObjectRequest> jsonObjectRequest = new ThreadLocal<JsonObjectRequest>() {
@Override
protected JsonObjectRequest initialValue() {
return new JsonObjectRequest(Request.Method.GET, webAdress,
null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
RESP = response.toString();
TEXT.setText("Response: " + RESP);
Log.d("TAG", "onResponse: " + webAdress);
Log.d("RESP", "onResponse: " + RESP);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
TEXT.setText("That didn't work!");
Log.d("TAG", "onErrorResponse: " + webAdress);
}
});
}
};
已修复问题,现在可以从办公室免费下载数据。