如何从Fragment中更改QueryUtils文件中存在的json对象的索引值？
这部分就在这里：JSONObject currentDay = dayArray.getJSONObject(0);
我想要为每个片段更改索引值,但无法绕过它.我尝试过意图并创建一个构造函数但失败了.
就像现在一样,应用程序正在“处理”所有显示星期一时间表的片段(JSONObject索引0).
QueryUtils.java
import android.text.TextUtils;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
public final class QueryUtils {
private static final String LOG_TAG = QueryUtils.class.getSimpleName();
//makeHttpRequest constants
private static final int READ_TIMEOUT = 10000 /* milliseconds */;
private static final int CONNECT_TIMEOUT = 15000 /* milliseconds */;
private static final int RESPONSE_CODE = 200 /*everything is OK*/;
public QueryUtils() {
}
public static List<Day> fetchDayData(String requestUrl) {
URL url = createUrl(requestUrl);
String jsonResponse = null;
try {
jsonResponse = makeHttpRequest(url);
} catch (IOException e) {
Log.e(LOG_TAG, "Problem making the HTTP request.", e);
}
List<Day> days = extractFeatureFromJson(jsonResponse);
return days;
}
private static URL createUrl(String stringUrl) {
URL url = null;
try {
url = new URL(stringUrl);
} catch (MalformedURLException e) {
Log.e(LOG_TAG, "Problem building the URL ", e);
}
return url;
}
private static String makeHttpRequest(URL url) throws IOException {
String jsonResponse = "";
if (url == null) {
return jsonResponse;
}
HttpURLConnection urlConnection = null;
InputStream inputStream = null;
try {
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setReadTimeout(READ_TIMEOUT);
urlConnection.setConnectTimeout(CONNECT_TIMEOUT);
urlConnection.setRequestMethod("GET");
urlConnection.connect();
if (urlConnection.getResponseCode() == RESPONSE_CODE) {
inputStream = urlConnection.getInputStream();
jsonResponse = readFromStream(inputStream);
} else {
Log.e(LOG_TAG, "Error response code: " + urlConnection.getResponseCode());
}
} catch (IOException e) {
Log.e(LOG_TAG, "Problem retrieving Berceni JSON results.", e);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (inputStream != null) {
inputStream.close();
}
}
return jsonResponse;
}
private static String readFromStream(InputStream inputStream) throws IOException {
StringBuilder output = new StringBuilder();
if (inputStream != null) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
BufferedReader reader = new BufferedReader(inputStreamReader);
String line = reader.readLine();
while (line != null) {
output.append(line);
line = reader.readLine();
}
}
return output.toString();
}
private static List<Day> extractFeatureFromJson(String dayJSON) {
if (TextUtils.isEmpty(dayJSON)) {
return null;
}
List<Day> days = new ArrayList<>();
//Try to parse
try {
JSONObject baseJsonResponse = new JSONObject(dayJSON);
JSONArray dayArray = baseJsonResponse.getJSONObject("schedule").getJSONArray("day");
JSONObject currentDay = dayArray.getJSONObject(0);
JSONArray getClasses = currentDay.getJSONArray("classes");
for (int j = 0; j < getClasses.length(); j++) {
JSONObject currentClass = getClasses.getJSONObject(j);
String retrieveCourseTitle = currentClass.getString("class");
String retrieveCourseTime = currentClass.getString("time");
String retrieveCourseTrainer = currentClass.getString("trainer");
String retrieveCourseCancelState = currentClass.getString("canceled");
Day day = new Day(retrieveCourseTitle, retrieveCourseTime, retrieveCourseTrainer, retrieveCourseCancelState);
days.add(day);
}
} catch (JSONException e) {
// If an error is thrown when executing any of the above statements in the "try" block,
// catch the exception here, so the app doesn't crash. Print a log message
// with the message from the exception.
Log.e("QueryUtils", "Problem parsing JSON results", e);
}
return days;
}
}
还有我的FragmentAdapter.java
import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class FragmentAdapter extends FragmentPagerAdapter {
private Context mContext;
public FragmentAdapter(Context context, FragmentManager fm) {
super(fm);
mContext = context;
}
@Override
public Fragment getItem(int position) {
if (position == 0) {
return new MondayFragment();
} else if (position == 1) {
return new ThursdayFragment();
} else if (position == 2) {
return new WednesdayFragment();
} else if (position == 3) {
return new ThursdayFragment();
} else if (position == 4) {
return new FridayFragment();
} else if (position == 5) {
return new SaturdayFragment();
} else {
return new SundayFragment();
}
}
/**
* Return the total number of pages.
*/
@Override
public int getCount() {
return 7;
}
@Override
public CharSequence getPageTitle(int position) {
if (position == 0) {
return mContext.getString(R.string.monday);
} else if (position == 1) {
return mContext.getString(R.string.tuesday);
} else if (position == 2) {
return mContext.getString(R.string.wednesday);
} else if (position == 3) {
return mContext.getString(R.string.thursday);
} else if (position == 4) {
return mContext.getString(R.string.friday);
} else if (position == 5) {
return mContext.getString(R.string.saturday);
} else {
return mContext.getString(R.string.sunday);
}
}
}
JSON示例响应
{
"schedule":{
"day":[
{
"id":"Monday",
"classes":[
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
},
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
}
]
},
{
"id":"Tuesday",
"classes":[
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
},
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
}
]
},
{
"id":"Wednesday",
"classes":[
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
},
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
}
]
},
{
"id":"Thursday",
"classes":[
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
},
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
}
]
},
{
"id":"Friday",
"classes":[
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
},
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
}
]
},
{
"id":"Saturday",
"classes":[
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
},
{
"class" : "Class",
"time" : "00:00",
"trainer" : "Teacher",
"canceled" : ""
}
]
},
{
"id":"Sunday",
"classes":[]
}
]
}
}
最佳答案 查看您的POJO,这并不明确等于您的JSON.
一天应宣布为：
class Day {
String id;
List<ClassDetail> classes;
}
class ClassDetail {
//all the details
}
我认为你错过了接受你的功能,跟随签名不是太明确.
List<Day> extractFeatureFromJson(String dayJSON)
为了使其更具可读性,我建议将其更改为：
(您可以使用Hashmap as recommended for @ρяσѕρєя)：
HashMap<String, ClassDetail> parseScheduleJson(String scheduleJSON)
并将每个ClassDetail添加到结果中
@Nullable
private static Map<String, List<ClassDetail>> parseScheduleJson(String scheduleJSON) {
if (TextUtils.isEmpty(scheduleJSON)) {
return null;
}
HashMap<String, List<ClassDetail>> result = new HashMap<>();
try {
JSONObject baseJsonResponse = new JSONObject(scheduleJSON);
JSONArray dayArray = baseJsonResponse.getJSONObject("schedule").getJSONArray("day");
for (int i = 0; i < dayArray.length(); i++) {
ArrayList<ClassDetail> classes = new ArrayList<>();
JSONObject currentDay = dayArray.getJSONObject(i);
for (int j = 0; j < currentDay.getJSONArray("classes").length(); j++) {
JSONObject currentClass = currentDay.getJSONArray("classes").getJSONObject(j);
String retrieveCourseTitle = currentClass.getString("class");
String retrieveCourseTime = currentClass.getString("time");
String retrieveCourseTrainer = currentClass.getString("trainer");
String retrieveCourseCancelState = currentClass.getString("canceled");
classes.add(new ClassDetail(retrieveCourseTitle, retrieveCourseTime, retrieveCourseTrainer, retrieveCourseCancelState));
}
result.put(currentDay.getString("id"), classes);
}
} catch (JSONException e) {
// If an error is thrown when executing any of the above statements in the "try" block,
// catch the exception here, so the app doesn't crash. Print a log message
// with the message from the exception.
Log.e("QueryUtils", "Problem parsing JSON results", e);
return null;
}
return result;
}
在此之后,您可以使用以下方式访问当天的课程列表：
mymap.get("Monday");
mymap.get("Tuesday");
...
mymap.get("Sunday");
编辑：
恕我直言,你必须在你的活动中调用你的日常活动,并将地图结果注入你的FragmentPagerAdapter：
public FragmentAdapter(Context context, FragmentManager fm, Map<String, List<ClassDetail> schedule) {
super(fm);
mContext = context;
mSchedule = schedule;
}
@Override
public Fragment getItem(int position) {
if (position == 0) {
return MondayFragment.newInstance(mSchedule.get("Monday"));
//...
//same for all conditions
//...
} else {
return SundayFragment.newInstance(mSchedule.get("Sunday"));
}
}
之后使用newIntance pattern时,您可以将片段声明为：
private List<ClassDetail> mClasses;
public static MondayClassDetailFragment newInstance(ArrayList<ClassDetail> classes){
MondayClassDetailFragment myFragment = new MondayClassDetailFragment();
Bundle args = new Bundle();
args.putParcelableArrayList("classes", classes);
myFragment.setArguments(args);
return myFragment;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mClasses = getArguments().getParcelableArrayList("classes");
}
PS：在这些日子手动发出http请求和解析json是浪费精力.我建议你去看看图书馆这样做,尤其是retrofit,它被广泛使用并且有很好的文档记录.
