为什么我的JsonObjectRequest不工作？
为什么我的JsonObjectRequest不工作？
提问于 2015-03-25 12:36:15
我已经摆弄这个东西好几天了。不能正确处理。Android studio不允许我编译这个错误。因此，我有一个应用程序，其中有两个选项卡和两个片段。一个片段称为new，该片段获取json。但是我不能正确地做它。我已经上传了错误的图片和类文件。你能帮帮我吗？
错误：“无法解析构造函数JsonObjectRequest(int，java.lang.String，null.....)
new_fragment.java
public class new_fragment extends Fragment {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private String mParam1;
private String mParam2;
private VolleySingleton volleySingleton;
private ImageLoader imageLoader;
private RequestQueue requestQueue;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() !=null){
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
volleySingleton = VolleySingleton.getsInstance();
requestQueue = volleySingleton.getRequestQueue();
RequestQueue requestQueue = VolleySingleton.getsInstance().getRequestQueue();
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET,"http://10.0.8.152/json/new.json",null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
System.out.println(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(request);
}
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedIntanceState) {
setHasOptionsMenu(true);
View layout = inflater.inflate(R.layout.new_fragment, container, false);
return layout;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// TODO Auto-generated method stub
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.ref_menu, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// handle item selection
switch (item.getItemId()) {
case R.id.refreshico:
// do s.th.
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}VolleySingleton
public class VolleySingleton {
private static VolleySingleton sInstance = null;
private ImageLoader mImageLoader;
private RequestQueue mRequestQueue;
private VolleySingleton(){
mRequestQueue = Volley.newRequestQueue(appClass.getAppContext());
mImageLoader = new ImageLoader(mRequestQueue,new ImageLoader.ImageCache() {
private LruCache<String, Bitmap> cache = new LruCache<>((int)(Runtime.getRuntime().maxMemory()/1024)/8);
@Override
public Bitmap getBitmap(String url) {
return cache.get(url);
}
@Override
public void putBitmap(String url, Bitmap bitmap) {
cache.put(url, bitmap);
}
});
}
public static VolleySingleton getsInstance(){
if(sInstance==null){
sInstance = new VolleySingleton();
}
return sInstance;
}
public RequestQueue getRequestQueue(){
return mRequestQueue;
}
public ImageLoader getImageLoader(){
return mImageLoader;
}
}回答 6
Stack Overflow用户
发布于 2015-03-25 13:42:34
cast (字符串)null。
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET,"http://10.0.8.152/json/new.json",(String)null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
System.out.println(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});Stack Overflow用户
发布于 2015-03-25 20:24:51
new JsonObjectRequest采用第三个参数作为String requestBody
将null转换为字符串
或者，您可以创建一个空字符串，如String rBody = null;，然后将rBody作为第三个参数进行传递
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET,
"http://10.0.8.152/json/new.json", (String) null, // here
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
System.out.println(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(request);Stack Overflow用户
发布于 2016-01-27 05:19:57
对于现在正在尝试实现这一点的每个人:谷歌更改了jsonObjectRequest构造函数:现在您不再支持请求类型，而是首先提供url，然后提供null作为第二个参数，如果您想要get请求的话。例如：
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest("http://www.aaa.com/getJSON/dummyMeldung.json", null,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.getJSONArray("meldung");
for (int i = 0; i <= jsonArray.length(); i++) {
JSONObject meldung = jsonArray.getJSONObject(i);
String comment = meldung.getString("comment");
Log.d("ausgabe", comment);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/29247525
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