我想通过MainActivity访问Fragment方法，当然，答案但是在那种方法中，我想要改变RecyclerView的那个项目但它没有改变我的麻烦在哪里？
在updatefrag_app方法中我得到了一个日志，所以我想我在这里工作但是RecyclerView没有更新。
我的名字是c：
public class MainActivity extends BaseActivity{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
db = new DBManager(this);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == Result_buy_image) {
if (resultCode == Activity.RESULT_OK) {
String result = data.getStringExtra("result");
String price = null,link = null,type = null,position = null;
try {
JSONObject jsonObject = new JSONObject(result);
type = jsonObject.getString("type").toString();
price = jsonObject.getString("price").toString();
link = jsonObject.getString("link").toString();
position = jsonObject.getString("position").toString();
} catch (JSONException e) {
e.printStackTrace();
}
int money = SSSP.getInstance(this).getInt("money", 0);
int NewMoney = money - (Integer.parseInt(price));
SSSP.getInstance(this).putInt("money", NewMoney);
navUsername.setText(NewMoney + "");
db.open();
db.insert_purchased(price, link);
db.close();
// call Fragment method
Frag_Post_App fragment = (Frag_Post_App) getSupportFragmentManager().
findFragmentByTag("Frag_Post_App");
fragment.updatefrag_app(position);
if (resultCode == Activity.RESULT_CANCELED) {
}
}
}
和片段：
public class Frag_Post_App extends BaseFragment {
private String TAG = "Frag_Post_App";
private List<Holder> arrayList = new ArrayList<>();
private RecyclerView recyclerView;
private Adapter_App mAdapter;
private View view;
private String cat_id, file_php = "";
private LinearLayout ll_pBar_ring_post;
private int counter = -1;
private boolean checkExistItem = true;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
view = inflater.inflate(R.layout.frag_post_category_app, container, false);
Bundle bundle = this.getArguments();
if (bundle != null) {
cat_id = bundle.getString("id", "favorite");
file_php = bundle.getString("filephp", "");
Log.d(TAG, "file_php: " + file_php);
}
ll_pBar_ring_post = (LinearLayout) view.findViewById(R.id.ll_pBar_ring_post);
new DownloadFilesTask(cat_id, "1").execute();
return view;
}
@Override
protected int getFragmentLayout() {
return 0;
}
private void recycler() {
counter = 1;
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView_appp_post);
mAdapter = new Adapter_App(arrayList, getActivity(), "post");
recyclerView.setHasFixedSize(true);
StaggeredGridLayoutManager gridLayoutManager =
new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
RecyclerView.LayoutManager mLayoutManager =
new LinearLayoutManager(getActivity().getApplicationContext());
recyclerView.setLayoutManager(gridLayoutManager);
DefaultItemAnimator animator = new DefaultItemAnimator() {
@Override
public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder) {
return true;
}
};
recyclerView.setItemAnimator(animator);
recyclerView.setAdapter(mAdapter);
mAdapter.notifyDataSetChanged();
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (!recyclerView.canScrollVertically(1)) {
if (checkExistItem) {
counter = ++counter;
new DownloadFilesTask(cat_id, counter + "").execute();
}
}
}
});
}
private class DownloadFilesTask extends AsyncTask<Void, Integer, String> {
String cat_id;
String page;
public DownloadFilesTask(String cat_id, String page) {
this.cat_id = cat_id;
this.page = page;
}
protected String doInBackground(Void... urls) {
String parsedString = "";
try {
URL url = new URL(file_php);
URLConnection conn = url.openConnection();
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setReadTimeout(50000);
httpConn.setConnectTimeout(50000);
httpConn.setUseCaches(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("POST");
httpConn.setChunkedStreamingMode(0);
httpConn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
httpConn.setRequestProperty("Accept-Encoding", "identity");
conn.setDoInput(true);
conn.setDoOutput(true);
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("cat_id", cat_id)
.appendQueryParameter("page", page);
String query = builder.build().getEncodedQuery();
OutputStream os = new BufferedOutputStream(conn.getOutputStream());
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
try {
httpConn.connect();
InputStream inputStream = null;
if (httpConn.getResponseCode() >= 400) {
inputStream = new BufferedInputStream(httpConn.getErrorStream());
} else {
inputStream = new BufferedInputStream(httpConn.getInputStream());
}
parsedString = StreamToString(inputStream);
} finally {
httpConn.disconnect();
}
} catch (Exception e) {
e.printStackTrace();
}
return parsedString;
}
protected void onProgressUpdate(Integer... progress) {
}
protected void onPostExecute(String result) {// showDialog("Downloaded " + result + " bytes");
Log.d(TAG, "result: " + result);
if (result != null) {
ll_pBar_ring_post.setVisibility(View.GONE);
pars(result);
} else {
Log.d(TAG, "resultIsNull: " + result);
}
}
}
private void pars(String res) {
Log.d(TAG, "pars: " + res);
try {
JSONArray jsonarray = new JSONArray(res);
if (jsonarray.length() > 0) {
checkExistItem = true;
SSSP.getInstance(getActivity()).putString(spResult, res);
for (int i = 0; i < jsonarray.length(); i++) {
JSONObject jsonobject = jsonarray.getJSONObject(i);
String post_id = jsonobject.getString("ID");
String post_link = jsonobject.getString("post_link");
String post_link_low = jsonobject.getString("post_link_low");
String like = jsonobject.getString("like");
String composer = jsonobject.getString("composer");
String price = jsonobject.getString("price");
String post_title = jsonobject.getString("post_title");
String thumbnail_url = jsonobject.getString("thumbnail_url");
String the_content = jsonobject.getString("the_content");
String advertise = jsonobject.getString("advertise");
String advertise_link = jsonobject.getString("advertise_link");
arrayList.add(new Holder(the_content, post_title + "", post_link + "", post_link_low + ""
, thumbnail_url + "", like + "", advertise, advertise_link, price + ""));
}
} else {
checkExistItem = false;
Log.d(TAG, "checkExistItem is false: ");
}
} catch (JSONException e) {
e.printStackTrace();
}
recycler();
}
public void updatefrag_app(String position) {
Log.d(TAG, "updatefrag_app: " + position);
mAdapter.notifyItemChanged(Integer.parseInt(position));
}
和适配器是：
public class Adapter_App extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<Holder> holder_s;
private Activity context;
private String TAG = "Adapter_App_log";
private String layout = "";
private DBManager db;
private int pos = -1;
public Adapter_App(List<Holder> holder_s, Activity context, String layout) {
this.holder_s = holder_s;
this.context = context;
this.layout = layout;
db = new DBManager(context);
}
public class viewHolderPost extends RecyclerView.ViewHolder {
private SSTextView number_like, title_app, link_google, content_app, price;
private LinearLayout ll_item_recy;
private ImageView img, dowload_app, like;
viewHolderPost(View itemView) {
super(itemView);
number_like = (SSTextView) itemView.findViewById(R.id.number_like_app);
price = (SSTextView) itemView.findViewById(R.id.price_app);
title_app = (SSTextView) itemView.findViewById(R.id.title_app);
link_google = (SSTextView) itemView.findViewById(R.id.link_google);
content_app = (SSTextView) itemView.findViewById(R.id.content_app);
ll_item_recy = (LinearLayout) itemView.findViewById(R.id.ll_item_recy_app);
DisplayMetrics displayMetrics = new DisplayMetrics();
context.getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int width = displayMetrics.widthPixels;
int height = displayMetrics.heightPixels;
ll_item_recy.getLayoutParams().width = width / 2;
ll_item_recy.getLayoutParams().height = height / 2;
img = (ImageView) itemView.findViewById(R.id.img_app);
dowload_app = (ImageView) itemView.findViewById(R.id.dowload_app);
like = (ImageView) itemView.findViewById(R.id.like_app);
}
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder = null;
Log.d(TAG, "onCreateViewHolder: ");
viewHolder = new viewHolderPost(LayoutInflater.from(context)
.inflate(R.layout.list_item_app, parent, false));
}
return viewHolder;
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
final Holder holder_ = holder_s.get(position);
final viewHolderPost holderPOST = (viewHolderPost) holder;
holderPOST.title_app.setText(holder_.getTitle());
holderPOST.number_like.setText(holder_.getlike());
holderPOST.content_app.setText(holder_.getid()); // this content in id
String link = holder_.get_image_link().replace("http://localhost", "http://192.168.43.8");
Picasso.get().load(link).into(holderPOST.img);
holderPOST.dowload_app.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(holder_.getUrl()));
context.startActivity(browserIntent);
}
});
holderPOST.link_google.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(holder_.getUrl_low()));
context.startActivity(browserIntent);
}
});
File file1 = StringtoFile(holder_.getUrl());
if (Integer.parseInt(holder_.getprice()) > 0) {
db.open();
Boolean exist = db.CheckItemExist(
OpenHelper.TBL_PURCHASED
, OpenHelper.LINK_PURCHASE, holder_.getUrl()
);
Log.d(TAG, "exist : " + exist);
Log.d(TAG, "link : " + holder_.getUrl());
if (!exist) {
holderPOST.price.setVisibility(View.VISIBLE);
holderPOST.price.setText(holder_.getprice() + " T");
holderPOST.dowload_app.setVisibility(View.GONE);
} else {
holderPOST.price.setVisibility(View.GONE);
if (file1.exists()) {
try {
holderPOST.price.setVisibility(View.GONE);
} catch (Exception e) {
e.printStackTrace();
}
} else {
holderPOST.dowload_app.setVisibility(View.VISIBLE);
}
}
db.close();
}
if (file1.exists()) {
holderPOST.dowload_app.setVisibility(View.VISIBLE);
}
holderPOST.price.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int money = SSSP.getInstance(context).getInt("money", 0);
int price = Integer.parseInt(holder_.getprice());
if (money >= price) {
JSONObject object = new JSONObject();
try {
object.put("type", "app");
object.put("price", holder_.getprice());
object.put("link", holder_.getUrl());
object.put("position", holderPOST.getLayoutPosition());
} catch (JSONException e) {
e.printStackTrace();
}
Intent intent = new Intent(context, SSDialog.class);
intent.putExtra("STRING_I_NEED", object.toString());
intent.putExtra("tv_inDate", "alert");
intent.putExtra("msg", "Do you sure want to buy?");
intent.putExtra("yes", "Yes");
intent.putExtra("no", "No");
context.startActivityForResult(intent, Result_buy_image);
} else {
SSToast(context, "Inventory is not enough");
}
}
});
}
}
@Override
public int getItemCount() {
return holder_s.size();
}
好吧，我知道是什么原因导致这个，抛出你的代码，我找不到你在哪里更改数据连接的recyclerView。