Android 片段内的自定义列表不工作
我只是在一个片段中使用了一个自定义列表。我使用截图从api中检索了这些数据。它显示了以下错误。我正在想办法解决这个问题,有人能帮我吗Android 片段内的自定义列表不工作,android,nullpointerexception,fragment,Android,Nullpointerexception,Fragment,我只是在一个片段中使用了一个自定义列表。我使用截图从api中检索了这些数据。它显示了以下错误。我正在想办法解决这个问题,有人能帮我吗 java.lang.NullPointerException: Attempt to invoke virtual method 'com.android.volley.toolbox.ImageLoader com.example.user.ekta.AppController.getImageLoader()' on a null object referen
java.lang.NullPointerException: Attempt to invoke virtual method 'com.android.volley.toolbox.ImageLoader com.example.user.ekta.AppController.getImageLoader()' on a null object reference
at com.example.user.ekta.MyBookAdapter.<init>(MyBookAdapter.java:25)
at com.example.user.ekta.FullInfoTabFragment.onCreateView(FullInfoTabFragment.java:85).
java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法'com.android.volley.toolbox.ImageLoader com.example.user.ekta.AppController.getImageLoader()
位于com.example.user.ekta.MyBookAdapter.(MyBookAdapter.java:25)
在com.example.user.ekta.FullInfoTabFragment.onCreateView(FullInfoTabFragment.java:85)上。
这是我的片段类
package com.example.user.ekta;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonArrayRequest;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
public class FullInfoTabFragment extends Fragment {
private static final String EXTRA_SRORT_CARD_MODEL = "EXTRA_SRORT_CARD_MODEL";
// String transitionTag;
private SportCardModel sportCardModel;
private Toolbar toolbar;
private ImageView ivPhoto;
private static final String TAG = FullInfoTabFragment.class.getSimpleName();
private static final String url = "http://myeducationhunt.com/public/schools";
private ProgressDialog pDialog;
private List<MyBook> ourBooksListItems = new ArrayList<MyBook>();
private ListView listView;
private MyBookAdapter adapter;
public static FullInfoTabFragment newInstance(SportCardModel sportCardModel) {
FullInfoTabFragment fragment = new FullInfoTabFragment();
Bundle args = new Bundle();
args.putParcelable(EXTRA_SRORT_CARD_MODEL, sportCardModel);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
sportCardModel = getArguments().getParcelable(EXTRA_SRORT_CARD_MODEL);
}
if (savedInstanceState != null) {
sportCardModel = savedInstanceState.getParcelable(EXTRA_SRORT_CARD_MODEL);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_full_info, container, false);
toolbar = (Toolbar) view.findViewById(R.id.toolbar);
ivPhoto = (ImageView) view.findViewById(R.id.ivPhoto);
listView = (ListView) view.findViewById(R.id.list);
adapter = new MyBookAdapter(getActivity(), ourBooksListItems);
listView.setAdapter(adapter);
listView.setTextFilterEnabled(true);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// OurSchool ourSchool = new OurSchool();
// Intent i = new Intent(getContext(), SchoolDetails.class);
// i.putExtra("id", ourSchoolsListItems.get(position).schoolId);
// i.putExtra("name", ourSchoolsListItems.get(position).schoolName);
// i.putExtra("location", ourSchoolsListItems.get(position).schoolLocation);
// i.putExtra("logo", ourSchoolsListItems.get(position).schoolLogo);
// i.putExtra("email", ourSchoolsListItems.get(position).schoolEmail);
// i.putExtra("website", ourSchoolsListItems.get(position).schoolWebsite);
// i.putExtra("created_at", ourSchoolsListItems.get(position).createdAt);
// i.putExtra("updated_at", ourSchoolsListItems.get(position).updatedAt);
// startActivity(i);
}
});
pDialog = new ProgressDialog(getActivity());
// Showing progress dialog before making http request
pDialog.setMessage("Loading…");
pDialog.show();
// Creating volley request obj
JsonArrayRequest schoolRequest = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
pDialog.hide();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
MyBook myBook = new MyBook();
myBook.bookName = obj.getString("name");
myBook.bookAuthor = obj.getString("location");
myBook.bookCover= obj.getString("logo");
// adding schools to ourSchool list
ourBooksListItems.add(myBook);
} catch (JSONException e) {
e.printStackTrace();
}
}
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
pDialog.hide();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(schoolRequest);
return view;
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
toolbar.setTitle(sportCardModel.getSportTitle());
toolbar.setNavigationIcon(R.drawable.ic_back);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
getActivity().onBackPressed();
}
});
toolbar.setBackgroundColor(ContextCompat.getColor(getContext(), sportCardModel.getBackgroundColorResId()));
ivPhoto.setImageResource(sportCardModel.getImageResId());
}
@Override
public void onSaveInstanceState(Bundle outState) {
outState.putParcelable(EXTRA_SRORT_CARD_MODEL, sportCardModel);
super.onSaveInstanceState(outState);
}
static class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
/**
* Default divider will be used
*/
public DividerItemDecoration(Context context) {
final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
mDivider = styledAttributes.getDrawable(0);
styledAttributes.recycle();
}
/**
* Custom divider will be used
*/
public DividerItemDecoration(Context context, int resId) {
mDivider = ContextCompat.getDrawable(context, resId);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int top = child.getBottom() + params.bottomMargin;
int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
}
}
package com.example.user.ekta;
导入android.app.ProgressDialog;
导入android.content.Context;
导入android.content.Intent;
导入android.content.res.TypedArray;
导入android.graphics.Canvas;
导入android.graphics.drawable.drawable;
导入android.os.Bundle;
导入android.support.annotation.Nullable;
导入android.support.v4.app.Fragment;
导入android.support.v4.content.ContextCompat;
导入android.support.v7.widget.DefaultItemAnimator;
导入android.support.v7.widget.LinearLayoutManager;
导入android.support.v7.widget.RecyclerView;
导入android.support.v7.widget.Toolbar;
导入android.util.Log;
导入android.view.LayoutInflater;
导入android.view.MotionEvent;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.AdapterView;
导入android.widget.ImageView;
导入android.widget.ListView;
导入android.widget.Toast;
导入com.android.volley.Response;
导入com.android.volley.VolleyError;
导入com.android.volley.VolleyLog;
导入com.android.volley.toolbox.JsonArrayRequest;
导入org.json.JSONArray;
导入org.json.JSONException;
导入org.json.JSONObject;
导入java.util.ArrayList;
导入java.util.List;
公共类FullInfoTabFragment扩展了片段{
私有静态最终字符串EXTRA\u SRORT\u CARD\u MODEL=“EXTRA\u SRORT\u CARD\u MODEL”;
//字符串转换标记;
私人SportCardModel SportCardModel;
专用工具栏;
私人影像查看照片;
私有静态最终字符串标记=FullInfoTabFragment.class.getSimpleName();
私有静态最终字符串url=”http://myeducationhunt.com/public/schools";
私人对话;
private List-ourbookslist-items=new-ArrayList();
私有列表视图列表视图;
私有MyBookAdapter适配器;
公共静态FullInfoTabFragment新实例(SportCardModel SportCardModel){
FullInfoTabFragment=新的FullInfoTabFragment();
Bundle args=新Bundle();
参数。可随身携带(额外存储卡型号、运动卡型号);
fragment.setArguments(args);
返回片段;
}
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
如果(getArguments()!=null){
sportCardModel=getArguments().getParcelable(额外端口卡型号);
}
如果(savedInstanceState!=null){
sportCardModel=savedInstanceState.getParcelable(额外的存储卡型号);
}
}
@凌驾
创建视图上的公共视图(布局、充气机、视图组容器、,
Bundle savedInstanceState){
视图=充气机。充气(R.layout.fragment\u full\u info,container,false);
toolbar=(toolbar)view.findviewbyd(R.id.toolbar);
ivPhoto=(ImageView)view.findViewById(R.id.ivPhoto);
listView=(listView)view.findViewById(R.id.list);
adapter=新的MyBookAdapter(getActivity(),ourBookListItems);
setAdapter(适配器);
setTextFilterEnabled(true);
setOnItemClickListener(新的AdapterView.OnItemClickListener(){
@凌驾
public void onItemClick(AdapterView父对象、视图、整型位置、长id){
//我们的学校我们的学校=新的我们的学校();
//Intent i=新的Intent(getContext(),SchoolDetails.class);
//i.putExtra(“id”,我们的学校机构.get(position).schoolId);
//i.putExtra(“名称”,我们的学校名称。获取(职位)。学校名称);
//i.putExtra(“位置”,我们的学校列表.get(位置).schoolLocation);
//i.putExtra(“logo”,我们的学校机构.get(position).school logo);
//i.putExtra(“电子邮件”,我们的学校系统.get(position).schoolEmail);
//i.putExtra(“网站”,我们的学校网站.get(position).schoolWebsite);
//i.putExtra(“创建于”,我们的学校系统.get(position.createdAt);
//i.putExtra(“更新的”,我们的学校系统.get(position).updatedAt);
//星触觉(i);
}
});
pDialog=newprogressdialog(getActivity());
//在发出http请求之前显示进度对话框
设置消息(“加载…”);
pDialog.show();
//创建截击请求对象
JsonArrayRequest schoolRequest=新的JsonArrayRequest(url,
新的Response.Listener(){
@凌驾
公共void onResponse(JSONArray响应){
Log.d(TAG,response.toString());
pDialog.hide();
//解析json
对于(int i=0;ipackage com.example.user.ekta;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.NetworkImageView;
import java.util.List;
/**
* Created by user on 11/27/2016.
*/
public class MyBookAdapter extends BaseAdapter {
private Activity activity;
private LayoutInflater inflater;
private List<MyBook> ourbooksList;
ImageLoader imageLoader = AppController.getInstance().getImageLoader();
public MyBookAdapter(Activity activity, List<MyBook> ourbooksListsList) {
this.activity = activity;
this.ourbooksList = ourbooksListsList;
}
@Override
public int getCount() {
return ourbooksList.size();
}
@Override
public Object getItem(int location) {
return ourbooksList.get(location);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.list_books, null);
if (imageLoader == null)
imageLoader = AppController.getInstance().getImageLoader();
NetworkImageView bookCover = (NetworkImageView) convertView
.findViewById(R.id.bookCover);
TextView bookName = (TextView) convertView.findViewById(R.id.bookName);
TextView boookAuthor = (TextView) convertView.findViewById(R.id.bookAuthor);
MyBook m = ourbooksList.get(position);
bookCover.setImageUrl(m.getBookCover(), imageLoader);
bookName.setText("Name: " + m.getBookName());
boookAuthor.setText("Address: " + String.valueOf(m.getBookAuthor()));
return convertView;
}
}