我想在3 fragments中使用 json 显示网站数据！在 TAB 之间滑动时不重复数据。但是当点击 TAB 时，再次复制以前的数据！
要将数据从 AsyncTask 发送到碎片，请使用 EventBus 组件。
片段代码：
public class free_fragment extends Fragment {
private RecyclerView mRecyclerView;
private free_recycler_adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
private List<DataModel> dataModels = new ArrayList<DataModel>();
private Context context;
private boolean isDataFetched;
private boolean mIsVisibleToUser;
private View view;
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_free_layout, container, false);
context = getContext();
if (mIsVisibleToUser) {
LoadData();
}
///----- RecyclerView -----
mRecyclerView = (RecyclerView) view.findViewById(R.id.pdf_RecyclerView);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mAdapter = new free_recycler_adapter(context, dataModels);
mRecyclerView.setAdapter(mAdapter);
return view;
}
@Subscribe
public void onEvent(MyEvent event) {
List<DataModel> dataModels = event.getInfoModels();
/* if (dataModels.size() > 0) {
dataModels.remove(dataModels.size() - 1);
mAdapter.notifyItemRemoved(dataModels.size());
//mAdapter.setLoaded();
}*/
if (event.fragmentTag.equals("forfragment1")) {
mAdapter.add(dataModels);
isDataFetched = true;
mAdapter.notifyDataSetChanged();
}
}
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
mIsVisibleToUser = isVisibleToUser;
if (isVisibleToUser && !isDataFetched && getContext() != null) {
context = getContext();
LoadData(); //Remove this call from onCreateView
}
}
private void LoadData() {
freeDataInfo dataInfo = new freeDataInfo();
// here getMainDataInfo() should return the server response
dataInfo.getFreeDataInfo(context);
}
@Override
public void onResume() {
super.onResume();
EventBus.getDefault().register(this);
}
@Override
public void onPause() {
EventBus.getDefault().unregister(this);
super.onPause();
}
}
AsyncTask代码：
public class freeDataInfo {
private Context mContext;
private String ServerAddress = freeServer_IP.getFreeIP();
private DiskLruDataCache mDiskLruCache;
public void getFreeDataInfo(Context context) {
mContext = context;
this.mDiskLruCache=new DiskLruDataCache(context);
//new getInfo().execute(ServerAddress + "limit=10");
new getInfo().execute(ServerAddress);
}
private class getInfo extends AsyncTask<String, Void, String> {
EventBus bus = EventBus.getDefault();
private String ou_response;
private List<DataModel> infoModels = new ArrayList<>();
private ProgressDialog dialog;
@Override
protected void onPreExecute() {
//CustomProcessDialog.createAndShow(mContext);
//infoModels = new ArrayList<>();
// Initiate Progress
dialog = new ProgressDialog(mContext);
this.dialog.setMessage("شکیبا باشید...");
this.dialog.show();
infoModels.clear();
}
@Override
protected String doInBackground(String... params) {
OkHttpClient client = new OkHttpClient();
//String url = (String) params[0];
Request request = new Request.Builder()
//.url(ServerAddress + "limit=10")
.url(ServerAddress)
.cacheControl(CacheControl.FORCE_NETWORK)
.build();
Response response;
try {
if(CheckInternet.isConnected(mContext)) {
response = client.newCall(request).execute();
ou_response = response.body().string();
if (ou_response != null) {
mDiskLruCache.cacheToDisk(ServerAddress, ou_response);
}
response.body().close();
}
else{
ou_response=mDiskLruCache.fetchFromDiskCache(ServerAddress);
}
if (ou_response != null) {
try {
JSONObject postObj = new JSONObject(ou_response);
JSONArray postsArray = postObj.optJSONArray("result");
for (int i = 0; i <= postsArray.length(); i++) {
JSONObject postObject = (JSONObject) postsArray.get(i);
int id = postObject.getInt("id");
Log.d("id", String.valueOf(id));
String title = postObject.getString("title");
String description = postObject.getString("full_description");
String image = postObject.getString("image");
String category = postObject.getString("categoryName");
String date = postObject.getString("date");
String url = postObject.getString("url");
Log.d("Data", "Post ID: " + id);
Log.d("Data", "Post title: " + title);
Log.d("Data", "Post image: " + image);
Log.d("Data", "Post url: " + url);
Log.d("Data", "---------------------------------");
//Use the title and id as per your requirement
infoModels.add(new DataModel(id, title, description, category, date, url, image));
}
} catch (JSONException e) {
e.printStackTrace();
Log.e("error", String.valueOf(e));
}
}
} catch (IOException e) {
e.printStackTrace();
Log.e("error2", String.valueOf(e));
}
return ou_response;
}
@Override
protected void onPostExecute(String result) {
//CustomProcessDialog.dissmis();
//Stop Progress
if (dialog.isShowing()) {
dialog.dismiss();
}
if (result != null) {
bus.post(new MyEvent("forfragment1", infoModels));
} else {
Toast.makeText(mContext, "Check Internet", Toast.LENGTH_LONG).show();
}
}
}
}
适配器代码：
public class free_recycler_adapter extends RecyclerView.Adapter<free_recycler_adapter.ViewHolder> {
private List<DataModel> mDateSet;
private Context context;
// Provide a suitable constructor (depends on the kind of dataset)
public free_recycler_adapter(Context context, List<DataModel> dataSet) {
this.context = context;
this.mDateSet = dataSet;
}
// Create new views (invoked by the layout manager)
@Override
public free_recycler_adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.free_card_layout, parent, false);
// create ViewHolder
return new ViewHolder(view);
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
// - get data from your itemsData at this position
// - replace the contents of the view with that itemsData
viewHolder.free_titleText.setText(Html.fromHtml(mDateSet.get(position).getTitle()));
viewHolder.free_titleText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
v.getContext().startActivity(new Intent(v.getContext(), ContentPage.class)
.putExtra("title", mDateSet.get(position).getTitle())
.putExtra("desc", mDateSet.get(position).getDescription())
.putExtra("image", mDateSet.get(position).getImage())
.putExtra("url", mDateSet.get(position).getUrl())
.putExtra("category", mDateSet.get(position).getCategory())
.putExtra("date", mDateSet.get(position).getDate()));
}
});
Glide.with(context)
.load(mDateSet.get(position).getImage())
.placeholder(R.drawable.ic_download_image)
.crossFade()
.into(viewHolder.free_avatarImage);
viewHolder.free_avatarImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
v.getContext().startActivity(new Intent(v.getContext(), ContentPage.class)
.putExtra("title", mDateSet.get(position).getTitle())
.putExtra("desc", mDateSet.get(position).getDescription())
.putExtra("image", mDateSet.get(position).getImage())
.putExtra("url", mDateSet.get(position).getUrl())
.putExtra("category", mDateSet.get(position).getCategory())
.putExtra("date", mDateSet.get(position).getDate()));
}
});
viewHolder.free_descText.setText(Html.fromHtml(mDateSet.get(position).getDescription()));
viewHolder.free_descText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
v.getContext().startActivity(new Intent(v.getContext(), ContentPage.class)
.putExtra("title", mDateSet.get(position).getTitle())
.putExtra("desc", mDateSet.get(position).getDescription())
.putExtra("image", mDateSet.get(position).getImage())
.putExtra("url", mDateSet.get(position).getUrl())
.putExtra("category", mDateSet.get(position).getCategory())
.putExtra("date", mDateSet.get(position).getDate()));
}
});
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mDateSet.size();
}
public void remove(int position) {
mDateSet.remove(position);
notifyItemRemoved(position);
}
public void clear() {
mDateSet.clear();
notifyDataSetChanged();
}
public void add(List<DataModel> models) {
mDateSet.addAll(models);
notifyDataSetChanged();
}
public void update(List<DataModel> models) {
mDateSet.clear();
mDateSet.addAll(models);
notifyDataSetChanged();
}
// inner class to hold a reference to each item of RecyclerView
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView free_titleText, free_descText;
public ImageView free_avatarImage;
public ViewHolder(View itemLayoutView) {
super(itemLayoutView);
free_titleText = (TextView) itemLayoutView.findViewById(R.id.pdf_card_title);
free_descText = (TextView) itemLayoutView.findViewById(R.id.pdf_card_content);
free_avatarImage = (ImageView) itemLayoutView.findViewById(R.id.pdf_card_image);
}
}
}
主要活动代码：
public class Main_Page extends AppCompatActivity {
private CollapsingToolbarLayout mCollapsingToolbarLayout;
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private DrawerLayout mDrawer;
private NavigationView nvDrawer;
private ImageView menuImage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main__page);
CalligraphyConfig.initDefault(new CalligraphyConfig.Builder()
.setDefaultFontPath("fonts/iransans.ttf")
.setFontAttrId(R.attr.fontPath)
.build());
mCollapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar_layout);
//mCollapsingToolbarLayout.setTitle(getResources().getString(R.string.app_name));
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("");
//getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
nvDrawer = (NavigationView) findViewById(R.id.navigation_drawer);
menuImage = (ImageView) findViewById(R.id.DrawableMenu_image);
menuImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mDrawer.openDrawer(GravityCompat.END);
}
});
}
/**
* Adding custom view to tab
*/
private void setupTabIcons() {
TextView tabOne = (TextView) LayoutInflater.from(this).inflate(R.layout.custom_tab, null);
tabOne.setText(R.string.free_fragment_title);
tabOne.setCompoundDrawablesWithIntrinsicBounds(0, R.drawable.ic_download_image, 0, 0);
tabLayout.getTabAt(0).setCustomView(tabOne);
TextView tabTwo = (TextView) LayoutInflater.from(this).inflate(R.layout.custom_tab, null);
tabTwo.setText(R.string.paid_fragment_title);
tabTwo.setCompoundDrawablesWithIntrinsicBounds(0, R.drawable.ic_paid_download_image, 0, 0);
tabLayout.getTabAt(1).setCustomView(tabTwo);
TextView tabThree = (TextView) LayoutInflater.from(this).inflate(R.layout.custom_tab, null);
tabThree.setText(R.string.pdf_fragment_title);
tabThree.setCompoundDrawablesWithIntrinsicBounds(0, R.drawable.ic_pdf_icon, 0, 0);
tabLayout.getTabAt(2).setCustomView(tabThree);
}
/**
* Adding fragments to ViewPager
*
* @param viewPager
*/
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new free_fragment(), "رایگان ها");
adapter.addFrag(new paid_fragment(), "پرداختی ها");
adapter.addFrag(new pdf_fragment(), "مقالات");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
@Override
public void onBackPressed() {
if (mDrawer.isDrawerOpen(GravityCompat.END)) {
mDrawer.closeDrawers();
} else
super.onBackPressed();
}
@Override
protected void attachBaseContext(Context newBase) {
super.attachBaseContext(CalligraphyContextWrapper.wrap(newBase));
}
}
如何点击 TabLayout 来解决此问题而不是重复数据？
我很业余，我真的需要这个帮助，请帮助我。谢谢所有＆lt; 3
答案 0 :(得分：0)
检查注释的代码：它导致每次都向适配器添加dataModels。
@Subscribe
public void onEvent(MyEvent event) {
List<DataModel> dataModels = event.getInfoModels();
if (event.fragmentTag.equals("forfragment1")) {
//mAdapter.add(dataModels);
isDataFetched = true;
mAdapter.notifyDataSetChanged();
}
}
在你的适配器中，在add（）方法中，你要重新将数据添加到列表中，这是不必要的，调用notifyDataSetChanged会自动暗示原始数据已被更改的适配器。
只需在适配器上调用notifyDataSetChanged即可刷新更新后的数据。希望能帮助到你。
答案 1 :(得分：-1)
尝试
viewPager.setOffscreenPageLimit(3);