使用 RecycleView Fragments 滑动标签并滑动刷新
Sliding Tabs with RecycleView Fragments and Swipe to Refresh
我在实现包含 2 个片段和向下滑动以刷新布局的滑动选项卡 activity 时遇到一些问题，即实现向下滑动以刷新部分（其余工作正常）。
首先是我的 XML 个文件。
Main Activity XML ，其中包含包装在 SwipeRefreshLayout 中的 ViewPager :
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.popal.soul.MovieListActivityTEST">
<com.example.popal.soul.SlidingTabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="@color/ColorPrimary"/>
<android.support.v4.widget.SwipeRefreshLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/swipeContainer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:layout_weight="1">
</android.support.v4.view.ViewPager>
</android.support.v4.widget.SwipeRefreshLayout>
第一个选项卡 XML ，两个选项卡之一（两者都很相似，所以我只 post 一个）
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.v7.widget.RecyclerView
android:id="@+id/cardList"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
</RelativeLayout>
现在，我的主要 activity，它处理 ViewPager、Adapter 和 SlidingTabsLayout。
public class MovieListActivityTEST extends AppCompatActivity {
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
CharSequence Titles[]={"Home","Events"};
int Numboftabs =2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_list_activity_test);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true);
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
}
最后，我的第一个选项卡片段
public class Tab1 extends Fragment {
public MovieListAdapter movieListAdaptor;
public RecyclerView recycleList;
private SwipeRefreshLayout swipeContainer;
private List<MovieListAdapter.MovieDetails> movieList = new ArrayList<MovieListAdapter.MovieDetails>();
private ProgressBar progressBar;
private final static String MOVIES_POST_REQUEST ="//Long String, Edited out since it`s not relevant"
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1, container, false);
recycleList = (RecyclerView) v.findViewById(R.id.cardList);
progressBar = (ProgressBar) v.findViewById(R.id.progress_bar);
progressBar.setVisibility(View.VISIBLE);
swipeContainer = (SwipeRefreshLayout) v.findViewById(R.id.swipeContainer);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recycleList.setLayoutManager(llm);
swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
movieListAdaptor.clear();
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
swipeContainer.setRefreshing(false);
}
});
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
return v;
}
问题是，我在 swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {...} 方法中遇到 NULL 指针异常，我猜这是因为滑动刷新布局位于主 activity XML，而不是制表符片段。那么实现这个的正确方法是什么？我还尝试在其中一个选项卡 XML 中实施滑动以刷新布局，而不是像上面那样将 ViewPager 包装在其中，但是从选项卡滑动到另一个选项卡时它会崩溃。
这是 Tab1 中整个片段的代码，下面是 tobs 的答案
public class MoviesTabFragment extends Fragment implements Refreshable {
public MovieListAdapter movieListAdaptor;
public RecyclerView recycleList;
//private SwipeRefreshLayout swipeContainer;
public List<MovieListAdapter.MovieDetails> movieList = new ArrayList<MovieListAdapter.MovieDetails>();
public ProgressBar progressBar;
public final static String MOVIES_POST_REQUEST ="";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1, container, false);
recycleList = (RecyclerView) v.findViewById(R.id.cardList);
progressBar = (ProgressBar) v.findViewById(R.id.progress_bar);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recycleList.setLayoutManager(llm);
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
return v;
}
@Override
public void refresh() {
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
}
public class Send_data_to_server extends AsyncTask<String, Void, String> {
private String data_poster;
private String data_fanart;
// protected void onPreExecute() {
// progressBar.setVisibility(View.VISIBLE);
// }
protected String doInBackground(String... params)
{
String jason_data = params[0];
HttpClient http_con = new HttpClient();
String output_from_server = http_con.establish_con(jason_data);
Log.i("DataFromServer", output_from_server);
JSONObject json_Obj = null;
JSONObject child_obj = null; //creating the "result" object in the main JSON Object
try {
json_Obj = new JSONObject(output_from_server);
child_obj = create_subObject("result", json_Obj);
JSONArray jsonArray = child_obj.optJSONArray("movies");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String title_data = jsonObject.optString("label").toString();
String plot_data = jsonObject.optString("plot").toString();
String year_data = jsonObject.optString("year").toString();
String movie_id_data = jsonObject.optString("movieid").toString();
String imdb_score = jsonObject.optString("rating").toString();
String imdb_score_short = imdb_score.substring(0, 3);
JSONObject child_obj2 = create_subObject("art", jsonObject);
data_poster = child_obj2.optString("poster").toString();
data_fanart = child_obj2.optString("fanart").toString();
JSONEncodePosterFanart encodePosterFanart = new JSONEncodePosterFanart();
String jason_dataPoster = encodePosterFanart.GetPosterFanartEncodedURL(data_poster);
String jason_dataFanart = encodePosterFanart.GetPosterFanartEncodedURL(data_fanart);
HttpClient http = new HttpClient();
String output_from_serverPoster = http.establish_con(jason_dataPoster);
HttpClient http2 = new HttpClient();
String output_from_serverFanart = http2.establish_con(jason_dataFanart);
JSONPosterFanart poster_fanart = new JSONPosterFanart();
String post_dl = poster_fanart.GetPosterFanart(output_from_serverPoster);
JSONPosterFanart poster_fanart2 = new JSONPosterFanart();
String fanart_dl = poster_fanart2.GetPosterFanart(output_from_serverFanart);
if (null == movieList) {
movieList = new ArrayList<MovieListAdapter.MovieDetails>();
}
MovieListAdapter.MovieDetails item = new MovieListAdapter.MovieDetails(title_data+" ("+year_data+")", post_dl, fanart_dl,plot_data,movie_id_data,imdb_score_short);
movieList.add(item);
}
} catch (JSONException e) {
e.printStackTrace();
}
return output_from_server;
}
protected void onPostExecute(String output_from_server) {
super.onPostExecute(output_from_server);
//progressBar.setVisibility(View.INVISIBLE);
movieListAdaptor = new MovieListAdapter(getActivity(), movieList);
recycleList.setAdapter(movieListAdaptor);
}
private JSONObject create_subObject(String tagName, JSONObject jObj) throws JSONException {
JSONObject subObj = jObj.getJSONObject(tagName); //getJSONObject returns the value from tagName (in our case jason_Obj that is being passed ar a param)
return subObj;
}
}
}
和 RecycleView 适配器：
public class MovieListAdapter extends RecyclerView.Adapter<MovieListAdapter.MovieViewHolder> {
public List<MovieDetails> movieList;
private Context mContext;
public MovieListAdapter(Context mContext, List<MovieDetails> movieList) {
this.mContext = mContext;
this.movieList = movieList;
}
@Override
public int getItemCount() {
return movieList.size();
}
public void clear() {
movieList.clear();
notifyDataSetChanged();
}
@Override
public MovieViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.
from(viewGroup.getContext()).
inflate(R.layout.card_layout_movies_list, viewGroup, false);
return new MovieViewHolder(itemView);
}
@Override
public void onBindViewHolder(MovieViewHolder movieViewHolder, int i) {
MovieDetails mdet = movieList.get(i);
String fanart = "http://192.168.1.128/"+mdet.getImageViewFanart();
String poster = "http://192.168.1.128/"+mdet.getImageViewPoster();
Log.i("fanart", fanart);
Log.i("poster", poster);
movieViewHolder.vTitle.setText(mdet.Title);
Picasso.with(mContext).load(poster)
.resize(500, 746)
.error(R.drawable.poster_placeholder)
.placeholder(R.drawable.poster_placeholder)
.into(movieViewHolder.vPoster);
Picasso.with(mContext).load(fanart)
.resize(960, 540)
.error(R.drawable.fanart_placeholder)
.placeholder(R.drawable.fanart_placeholder)
.into(movieViewHolder.vFanart);
movieViewHolder.vplot = mdet.getPlot();
movieViewHolder.vmovie_id = mdet.getMovie_id();
}
public class MovieViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
protected TextView vTitle;
protected ImageView vPoster;
protected ImageView vFanart;
protected String vplot;
protected String vmovie_id;
protected String vimdb_score;
public MovieViewHolder(View v)
{
super(v);
vplot = new String();
vmovie_id = new String();
vimdb_score = new String();
vTitle = (TextView) v.findViewById(R.id.title);
vPoster = (ImageView) v.findViewById(R.id.imageViewPoster);
vFanart = (ImageView) v.findViewById(R.id.imageViewFanart);
v.setOnClickListener(this);
}
@Override
public void onClick(View v) {
int position = getLayoutPosition();
MovieDetails mov = movieList.get(position);
Intent intent = new Intent(mContext, MovieDetailsPageActivity.class);
Bundle bundle = new Bundle();
bundle.putString("movieid", mov.getMovie_id());
bundle.putString("plot", vplot);
bundle.putString("fanart_path", mov.getImageViewFanart());
bundle.putString("imdb_score", mov.getImdb_score());
intent.putExtras(bundle);
mContext.startActivity(intent);
}
}
public static class MovieDetails {
protected String Title;
protected String imageViewPoster;
protected String imageViewFanart;
protected String plot;
protected String movie_id;
protected String imdb_score;
public MovieDetails(String Title, String imageViewPoster,String imageViewFanart, String plot, String movie_id ,String imdb_score)
{
this.Title = Title;
this.imageViewPoster = imageViewPoster;
this.imageViewFanart = imageViewFanart;
this.plot = plot;
this.movie_id = movie_id;
this.imdb_score = imdb_score;
}
public String getTitle() {return Title;}
public String getImageViewPoster() {
return imageViewPoster;
}
public String getImageViewFanart() {
return imageViewFanart;
}
public String getPlot() {return plot;}
public String getMovie_id() {return movie_id;}
public String getImdb_score() {return imdb_score;}
}
}
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
CharSequence Titles[];
int NumbOfTabs;
public ViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
super(fm);
this.Titles = mTitles;
this.NumbOfTabs = mNumbOfTabsumb;
}
@Override
public Fragment getItem(int position) {
if(position == 0)
{
MoviesTabFragment moviesTabFragment = new MoviesTabFragment();
return moviesTabFragment;
}
else
{
TVShowsTabFragment TVShowsTabFragment = new TVShowsTabFragment();
return TVShowsTabFragment;
}
}
@Override
public CharSequence getPageTitle(int position) {
return Titles[position];
}
@Override
public int getCount() {
return NumbOfTabs;
}
您得到 NullPointerException 是因为您从 R.layout.tab_1 扩展了不包含 SwipeRefreshLayout.
的片段布局
如果您希望布局成为 ViewPager 的父布局，我建议您将管理 RefreshLayout 的代码移动到 MainActivity：
public class MovieListActivityTEST extends AppCompatActivity {
ViewPager pager;
ViewPagerAdapter adapter;
SwipeRefreshLayout refreshLayout;
SlidingTabLayout tabs;
CharSequence Titles[]={"Home","Events"};
int Numboftabs =2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_list_activity_test);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true);
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
// Assign your refresh layout
refreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipeContainer);
refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
Refreshable r = (Refreshable) adapter.getItemAt(pager.getCurrentItem());
r.refresh();
}
});
}
您的每个选项卡片段都实现了一个 Refreshable 接口：
public interface Refreshable {
void refresh();
}
并且您的适配器跟踪所有片段：
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
// list that keeps references to all attached Fragments
private SparseArray<Fragment> pages = new SparseArray<>();
...
public Fragment getItem(int position) {
Fragment f;
if(position == 0) {
...
} else { ... }
// add fragment to the list
pages.put(position, f);
}
public void destroyItem(ViewGroup container, int position, Object object) {
// remove fragment from list if it existed
if(pages.indexOfKey(position) >= 0) {
pages.remove(position);
}
super.destroyItem(container, position, object);
}
// return the attached Fragment that is associated with the given position
public Fragment getItemAt(int position) {
return pages.get(position);
}
}
我在实现包含 2 个片段和向下滑动以刷新布局的滑动选项卡 activity 时遇到一些问题，即实现向下滑动以刷新部分（其余工作正常）。
首先是我的 XML 个文件。
Main Activity XML ，其中包含包装在 SwipeRefreshLayout 中的 ViewPager :
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.popal.soul.MovieListActivityTEST">
<com.example.popal.soul.SlidingTabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="@color/ColorPrimary"/>
<android.support.v4.widget.SwipeRefreshLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/swipeContainer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:layout_weight="1">
</android.support.v4.view.ViewPager>
</android.support.v4.widget.SwipeRefreshLayout>
第一个选项卡 XML ，两个选项卡之一（两者都很相似，所以我只 post 一个）
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.v7.widget.RecyclerView
android:id="@+id/cardList"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
</RelativeLayout>
现在，我的主要 activity，它处理 ViewPager、Adapter 和 SlidingTabsLayout。
public class MovieListActivityTEST extends AppCompatActivity {
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
CharSequence Titles[]={"Home","Events"};
int Numboftabs =2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_list_activity_test);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true);
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
}
最后，我的第一个选项卡片段
public class Tab1 extends Fragment {
public MovieListAdapter movieListAdaptor;
public RecyclerView recycleList;
private SwipeRefreshLayout swipeContainer;
private List<MovieListAdapter.MovieDetails> movieList = new ArrayList<MovieListAdapter.MovieDetails>();
private ProgressBar progressBar;
private final static String MOVIES_POST_REQUEST ="//Long String, Edited out since it`s not relevant"
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1, container, false);
recycleList = (RecyclerView) v.findViewById(R.id.cardList);
progressBar = (ProgressBar) v.findViewById(R.id.progress_bar);
progressBar.setVisibility(View.VISIBLE);
swipeContainer = (SwipeRefreshLayout) v.findViewById(R.id.swipeContainer);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recycleList.setLayoutManager(llm);
swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
movieListAdaptor.clear();
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
swipeContainer.setRefreshing(false);
}
});
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
return v;
}
问题是，我在 swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {...} 方法中遇到 NULL 指针异常，我猜这是因为滑动刷新布局位于主 activity XML，而不是制表符片段。那么实现这个的正确方法是什么？我还尝试在其中一个选项卡 XML 中实施滑动以刷新布局，而不是像上面那样将 ViewPager 包装在其中，但是从选项卡滑动到另一个选项卡时它会崩溃。
这是 Tab1 中整个片段的代码，下面是 tobs 的答案
public class MoviesTabFragment extends Fragment implements Refreshable {
public MovieListAdapter movieListAdaptor;
public RecyclerView recycleList;
//private SwipeRefreshLayout swipeContainer;
public List<MovieListAdapter.MovieDetails> movieList = new ArrayList<MovieListAdapter.MovieDetails>();
public ProgressBar progressBar;
public final static String MOVIES_POST_REQUEST ="";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1, container, false);
recycleList = (RecyclerView) v.findViewById(R.id.cardList);
progressBar = (ProgressBar) v.findViewById(R.id.progress_bar);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recycleList.setLayoutManager(llm);
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
return v;
}
@Override
public void refresh() {
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
}
public class Send_data_to_server extends AsyncTask<String, Void, String> {
private String data_poster;
private String data_fanart;
// protected void onPreExecute() {
// progressBar.setVisibility(View.VISIBLE);
// }
protected String doInBackground(String... params)
{
String jason_data = params[0];
HttpClient http_con = new HttpClient();
String output_from_server = http_con.establish_con(jason_data);
Log.i("DataFromServer", output_from_server);
JSONObject json_Obj = null;
JSONObject child_obj = null; //creating the "result" object in the main JSON Object
try {
json_Obj = new JSONObject(output_from_server);
child_obj = create_subObject("result", json_Obj);
JSONArray jsonArray = child_obj.optJSONArray("movies");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String title_data = jsonObject.optString("label").toString();
String plot_data = jsonObject.optString("plot").toString();
String year_data = jsonObject.optString("year").toString();
String movie_id_data = jsonObject.optString("movieid").toString();
String imdb_score = jsonObject.optString("rating").toString();
String imdb_score_short = imdb_score.substring(0, 3);
JSONObject child_obj2 = create_subObject("art", jsonObject);
data_poster = child_obj2.optString("poster").toString();
data_fanart = child_obj2.optString("fanart").toString();
JSONEncodePosterFanart encodePosterFanart = new JSONEncodePosterFanart();
String jason_dataPoster = encodePosterFanart.GetPosterFanartEncodedURL(data_poster);
String jason_dataFanart = encodePosterFanart.GetPosterFanartEncodedURL(data_fanart);
HttpClient http = new HttpClient();
String output_from_serverPoster = http.establish_con(jason_dataPoster);
HttpClient http2 = new HttpClient();
String output_from_serverFanart = http2.establish_con(jason_dataFanart);
JSONPosterFanart poster_fanart = new JSONPosterFanart();
String post_dl = poster_fanart.GetPosterFanart(output_from_serverPoster);
JSONPosterFanart poster_fanart2 = new JSONPosterFanart();
String fanart_dl = poster_fanart2.GetPosterFanart(output_from_serverFanart);
if (null == movieList) {
movieList = new ArrayList<MovieListAdapter.MovieDetails>();
}
MovieListAdapter.MovieDetails item = new MovieListAdapter.MovieDetails(title_data+" ("+year_data+")", post_dl, fanart_dl,plot_data,movie_id_data,imdb_score_short);
movieList.add(item);
}
} catch (JSONException e) {
e.printStackTrace();
}
return output_from_server;
}
protected void onPostExecute(String output_from_server) {
super.onPostExecute(output_from_server);
//progressBar.setVisibility(View.INVISIBLE);
movieListAdaptor = new MovieListAdapter(getActivity(), movieList);
recycleList.setAdapter(movieListAdaptor);
}
private JSONObject create_subObject(String tagName, JSONObject jObj) throws JSONException {
JSONObject subObj = jObj.getJSONObject(tagName); //getJSONObject returns the value from tagName (in our case jason_Obj that is being passed ar a param)
return subObj;
}
}
}
和 RecycleView 适配器：
public class MovieListAdapter extends RecyclerView.Adapter<MovieListAdapter.MovieViewHolder> {
public List<MovieDetails> movieList;
private Context mContext;
public MovieListAdapter(Context mContext, List<MovieDetails> movieList) {
this.mContext = mContext;
this.movieList = movieList;
}
@Override
public int getItemCount() {
return movieList.size();
}
public void clear() {
movieList.clear();
notifyDataSetChanged();
}
@Override
public MovieViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.
from(viewGroup.getContext()).
inflate(R.layout.card_layout_movies_list, viewGroup, false);
return new MovieViewHolder(itemView);
}
@Override
public void onBindViewHolder(MovieViewHolder movieViewHolder, int i) {
MovieDetails mdet = movieList.get(i);
String fanart = "http://192.168.1.128/"+mdet.getImageViewFanart();
String poster = "http://192.168.1.128/"+mdet.getImageViewPoster();
Log.i("fanart", fanart);
Log.i("poster", poster);
movieViewHolder.vTitle.setText(mdet.Title);
Picasso.with(mContext).load(poster)
.resize(500, 746)
.error(R.drawable.poster_placeholder)
.placeholder(R.drawable.poster_placeholder)
.into(movieViewHolder.vPoster);
Picasso.with(mContext).load(fanart)
.resize(960, 540)
.error(R.drawable.fanart_placeholder)
.placeholder(R.drawable.fanart_placeholder)
.into(movieViewHolder.vFanart);
movieViewHolder.vplot = mdet.getPlot();
movieViewHolder.vmovie_id = mdet.getMovie_id();
}
public class MovieViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
protected TextView vTitle;
protected ImageView vPoster;
protected ImageView vFanart;
protected String vplot;
protected String vmovie_id;
protected String vimdb_score;
public MovieViewHolder(View v)
{
super(v);
vplot = new String();
vmovie_id = new String();
vimdb_score = new String();
vTitle = (TextView) v.findViewById(R.id.title);
vPoster = (ImageView) v.findViewById(R.id.imageViewPoster);
vFanart = (ImageView) v.findViewById(R.id.imageViewFanart);
v.setOnClickListener(this);
}
@Override
public void onClick(View v) {
int position = getLayoutPosition();
MovieDetails mov = movieList.get(position);
Intent intent = new Intent(mContext, MovieDetailsPageActivity.class);
Bundle bundle = new Bundle();
bundle.putString("movieid", mov.getMovie_id());
bundle.putString("plot", vplot);
bundle.putString("fanart_path", mov.getImageViewFanart());
bundle.putString("imdb_score", mov.getImdb_score());
intent.putExtras(bundle);
mContext.startActivity(intent);
}
}
public static class MovieDetails {
protected String Title;
protected String imageViewPoster;
protected String imageViewFanart;
protected String plot;
protected String movie_id;
protected String imdb_score;
public MovieDetails(String Title, String imageViewPoster,String imageViewFanart, String plot, String movie_id ,String imdb_score)
{
this.Title = Title;
this.imageViewPoster = imageViewPoster;
this.imageViewFanart = imageViewFanart;
this.plot = plot;
this.movie_id = movie_id;
this.imdb_score = imdb_score;
}
public String getTitle() {return Title;}
public String getImageViewPoster() {
return imageViewPoster;
}
public String getImageViewFanart() {
return imageViewFanart;
}
public String getPlot() {return plot;}
public String getMovie_id() {return movie_id;}
public String getImdb_score() {return imdb_score;}
}
}
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
CharSequence Titles[];
int NumbOfTabs;
public ViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
super(fm);
this.Titles = mTitles;
this.NumbOfTabs = mNumbOfTabsumb;
}
@Override
public Fragment getItem(int position) {
if(position == 0)
{
MoviesTabFragment moviesTabFragment = new MoviesTabFragment();
return moviesTabFragment;
}
else
{
TVShowsTabFragment TVShowsTabFragment = new TVShowsTabFragment();
return TVShowsTabFragment;
}
}
@Override
public CharSequence getPageTitle(int position) {
return Titles[position];
}
@Override
public int getCount() {
return NumbOfTabs;
}
您得到 NullPointerException 是因为您从 R.layout.tab_1 扩展了不包含 SwipeRefreshLayout.
如果您希望布局成为 ViewPager 的父布局，我建议您将管理 RefreshLayout 的代码移动到 MainActivity：
public class MovieListActivityTEST extends AppCompatActivity {
ViewPager pager;
ViewPagerAdapter adapter;
SwipeRefreshLayout refreshLayout;
SlidingTabLayout tabs;
CharSequence Titles[]={"Home","Events"};
int Numboftabs =2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_list_activity_test);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true);
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
// Assign your refresh layout
refreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipeContainer);
refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
Refreshable r = (Refreshable) adapter.getItemAt(pager.getCurrentItem());
r.refresh();
}
});
}
您的每个选项卡片段都实现了一个 Refreshable 接口：
public interface Refreshable {
void refresh();
}
并且您的适配器跟踪所有片段：
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
// list that keeps references to all attached Fragments
private SparseArray<Fragment> pages = new SparseArray<>();
...
public Fragment getItem(int position) {
Fragment f;
if(position == 0) {
...
} else { ... }
// add fragment to the list
pages.put(position, f);
}
public void destroyItem(ViewGroup container, int position, Object object) {
// remove fragment from list if it existed
if(pages.indexOfKey(position) >= 0) {
pages.remove(position);
}
super.destroyItem(container, position, object);
}
// return the attached Fragment that is associated with the given position
public Fragment getItemAt(int position) {
return pages.get(position);
}
}