我有一个 Activity ，其中我使用回收 View 将所有项目显示为列表。在同一 Activity 中，我提供了添加新项目的功能。一切正常。项目正在添加到我的数据库中并显示在列表中。我在回收 View 上添加了分页，它也工作正常。我想要的是，当用户在新数据添加到数据库的同时添加新项目但它没有在列表中更新时。当用户按返回并再次开始 Activity 时，它会显示在列表中。我想同时添加新项目而不滚动列表或不返回。
时间线 Activity .java
public class TimelineActivity extends AppCompatActivity implements RecyclerView.OnScrollChangeListener {
private static final String TAG = MainActivity.class.getSimpleName();
private RecyclerView listView;
private RecyclerView.LayoutManager layoutManager;
private RecyclerView.Adapter adapter;
private TimeLineListAdapter listAdapter;
private List<TimeLineItem> timeLineItems;
private int requestCount = 1;
private ProgressDialog pDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_timeline);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
listView = (RecyclerView) findViewById(R.id.list);
listView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(this);
listView.setLayoutManager(layoutManager);
btnPost = (Button) findViewById(R.id.btnPost);
//Adding an scroll change listener to recyclerview
listView.setOnScrollChangeListener(this);
// Progress dialog
pDialog = new ProgressDialog(this);
pDialog.setCancelable(false);
cd = new ConnectionDetector(this);
isInternetPresent = cd.isConnectingToInternet();
db = new SQLiteHandler(this);
// session manager
session = new SessionManager(this);
/*pref = getApplicationContext().getSharedPreferences("MayahudiPref", 0);
editor = pref.edit();*/
buttonClickEvent();
// Fetching user details from sqlite
HashMap<String, String> user = db.getUserDetails();
id = user.get("id");
token = user.get("token");
getData();
timeLineItems = new ArrayList<>();
adapter = new TimeLineListAdapter(timeLineItems, this);
listView.setAdapter(adapter);
Timer autoRefresh;
autoRefresh=new Timer();
autoRefresh.schedule(new TimerTask() {
@Override
public void run() {
runOnUiThread(new Runnable() {
public void run() {
getTimeLineData(token, "1");
}
});
}
}, 0, 2000);
}
public void getTimeLineData(final String token, final String page) {
String tag_string_req = "req_register";
// making fresh volley request and getting json
StringRequest strReq = new StringRequest(Request.Method.POST, AppConfig.timeline, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
VolleyLog.d(TAG, "Response: " + response.toString());
if (response != null) {
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("status");
String message = jObj.getString("message");
if (error) {
totalPages = jObj.getInt("totalPages");
pageCount = jObj.getInt("page");
int limit = jObj.getInt("limit");
parseJsonFeed(response);
}
} catch (Exception e) {
}
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
}
}) {
@Override
protected Map<String, String> getParams() {
// Posting params to register url
Map<String, String> params = new HashMap<String, String>();
params.put("my_token", token);
params.put("page", page);
params.put("limit", "5");
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
private void parseJsonFeed(String response) {
try {
JSONObject jsonObj = new JSONObject(response);
JSONArray feedArray = jsonObj.getJSONArray("data");
for (int i = 0; i < feedArray.length(); i++) {
JSONObject feedObj = (JSONObject) feedArray.get(i);
TimeLineItem item = new TimeLineItem();
item.setId(feedObj.getInt("id"));
item.setName(feedObj.getString("name"));
item.setLname(feedObj.getString("lname"));
// Image might be null sometimes
String image = feedObj.isNull("image") ? null : feedObj
.getString("image");
if (image.equals("")) {
item.setImge(image);
} else {
item.setImge(AppConfig.storyPic + image);
}
item.setStatus(feedObj.getString("story_text"));
item.setProfilePic(AppConfig.profilePic + feedObj.getString("profile_pic"));
item.setTimeStamp(feedObj.getString("time_stamp"));
item.setIsLike(feedObj.getInt("is_like"));
item.setTotalLikes(feedObj.getString("total_likes"));
item.setTotalComment(feedObj.getString("total_comments"));
/*// url might be null sometimes
String feedUrl = feedObj.isNull("url") ? null : feedObj
.getString("url");
item.setUrl(feedUrl);*/
timeLineItems.add(item);
}
// notify data changes to list adapater
adapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
//This method will get data from the web API
private void getData() {
//Adding the method to the queue by calling the method getDataFromServer
getTimeLineData(token, String.valueOf(requestCount));
//Incrementing the request counter
requestCount++;
}
//This method would check that the recyclerview scroll has reached the bottom or not
private boolean isLastItemDisplaying(RecyclerView recyclerView) {
if (recyclerView.getAdapter().getItemCount() != 0) {
int lastVisibleItemPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
if (lastVisibleItemPosition != RecyclerView.NO_POSITION && lastVisibleItemPosition == recyclerView.getAdapter().getItemCount() - 1)
return true;
}
return false;
}
@Override
public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
//Ifscrolled at last then
if (isLastItemDisplaying(listView)) {
//Calling the method getdata again
getData();
}
}
public void buttonClickEvent() {
btnPost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (isInternetPresent) {
String text = txtStatusBox.getText().toString().trim();
if (!text.isEmpty()) {
if (thumbnail != null) {
String image = getStringImage(thumbnail);
JSONObject student2 = new JSONObject();
try {
student2.put("size", "1000");
student2.put("type", "image/jpeg");
student2.put("data", image);
} catch (JSONException e) {
e.printStackTrace();
}
addStory(text, token, String.valueOf(student2));
} else {
addStory(text, token, "");
}
} else {
Toast.makeText(TimelineActivity.this, "Please add some text or image.", Toast.LENGTH_SHORT).show();
}
} else {
final SweetAlertDialog alert = new SweetAlertDialog(TimelineActivity.this, SweetAlertDialog.WARNING_TYPE);
alert.setTitleText("No Internet");
alert.setContentText("No connectivity. Please check your internet.");
alert.show();
}
}
});
btnCancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
txtStatusBox.setText("");
imgImageUpload.setImageBitmap(null);
imgImageUpload.setBackgroundResource(R.drawable.image);
Toast.makeText(TimelineActivity.this, message, Toast.LENGTH_SHORT).show();
slidingUpPanelLayout.setPanelState(SlidingUpPanelLayout.PanelState.COLLAPSED);
}
});
imgImageUpload.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
selectImage();
}
});
/*fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
myDialogFragment.show(getFragmentManager(), "MyDialogFragment");
//Toast.makeText(TimelineActivity.this, "Floating Button", Toast.LENGTH_SHORT).show();
}
});*/
}
private void addStory(final String story_text, final String token, final String image) {
// Tag used to cancel the request
String tag_string_req = "req_register";
pDialog.setMessage("Please wait ...");
showDialog();
StringRequest strReq = new StringRequest(Request.Method.POST, AppConfig.addStory, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
hideDialog();
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("status");
message = jObj.getString("message");
if (error) {
txtStatusBox.setText("");
imgImageUpload.setImageBitmap(null);
imgImageUpload.setBackgroundResource(R.drawable.image);
Toast.makeText(TimelineActivity.this, message, Toast.LENGTH_SHORT).show();
slidingUpPanelLayout.setPanelState(SlidingUpPanelLayout.PanelState.COLLAPSED);
} else {
// Error occurred in registration. Get the error
// message
String errorMsg = jObj.getString("message");
Toast.makeText(TimelineActivity.this, errorMsg, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(TimelineActivity.this, "Oops something went wrong...", Toast.LENGTH_LONG).show();
hideDialog();
}
}) {
@Override
protected Map<String
, String> getParams() {
// Posting params to register url
Map<String, String> params = new HashMap<String, String>();
params.put("my_token", token);
params.put("story_text", story_text);
params.put("image", image);
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
private void showDialog() {
if (!pDialog.isShowing())
pDialog.show();
}
private void hideDialog() {
if (pDialog.isShowing())
pDialog.dismiss();
}
}
TimeLineListAdapter.java
public class TimeLineListAdapter extends RecyclerView.Adapter<TimeLineListAdapter.ViewHolder> {
private List<TimeLineItem> timeLineItems;
String message, storyId, token;
private Context context;
ImageLoader imageLoader = AppController.getInstance().getImageLoader();
public TimeLineListAdapter(List<TimeLineItem> timeLineItems, Context context) {
super();
this.context = context;
this.timeLineItems = timeLineItems;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.timeline_item, parent, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
//Getting the particular item from the list
TimeLineItem item = timeLineItems.get(position);
if (item.getTotalLikes().equals("0")){
holder.txtLike.setText("");
}else {
holder.txtLike.setText(item.getTotalLikes());
}
if (item.getTotalComment().equals("0")){
holder.txtComment.setText("");
}else {
holder.txtComment.setText("("+item.getTotalComment()+")");
}
if (item.getIsLike() == 0){
}else {
holder.imageLike.setImageBitmap(null);
holder.imageLike.setBackgroundResource(R.drawable.islike);
holder.txtLike.setTextColor(Color.parseColor("#3498db"));
}
holder.name.setText(item.getName() + " " + item.getLname());
/*Long.parseLong(item.getTimeStamp()),
System.currentTimeMillis(), DateUtils.SECOND_IN_MILLIS);*/
holder.timestamp.setText(item.getTimeStamp());
// Chcek for empty status message
if (!TextUtils.isEmpty(item.getStatus())) {
holder.statusMsg.setText(item.getStatus());
holder.statusMsg.setVisibility(View.VISIBLE);
} else {
// status is empty, remove from view
holder.statusMsg.setVisibility(View.GONE);
}
// Checking for null feed url
if (item.getUrl() != null) {
holder.url.setText(Html.fromHtml("<a href=\"" + item.getUrl() + "\">"
+ item.getUrl() + "</a> "));
// Making url clickable
holder.url.setMovementMethod(LinkMovementMethod.getInstance());
holder.url.setVisibility(View.VISIBLE);
} else {
// url is null, remove from the view
holder.url.setVisibility(View.GONE);
}
// user profile pic
holder.profilePic.setImageUrl(item.getProfilePic(), imageLoader);
// Feed image
if (item.getImge() != null) {
holder.feedImageView.setImageUrl(item.getImge(), imageLoader);
holder.feedImageView.setVisibility(View.VISIBLE);
holder.feedImageView
.setResponseObserver(new TimeLineImageView.ResponseObserver() {
@Override
public void onError() {
}
@Override
public void onSuccess() {
}
});
} else {
holder.feedImageView.setVisibility(View.GONE);
}
}
@Override
public int getItemCount() {
return timeLineItems.size();
}
class ViewHolder extends RecyclerView.ViewHolder{
TextView name, timestamp, statusMsg, url, txtLike, txtComment, txtCommentLabel;
NetworkImageView profilePic;
TimeLineImageView feedImageView;
ImageView imageLike;
//Initializing Views
public ViewHolder(View itemView) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.name);
timestamp = (TextView) itemView.findViewById(R.id.timestamp);
statusMsg = (TextView) itemView.findViewById(R.id.txtStatusMsg);
url = (TextView) itemView.findViewById(R.id.txtUrl);
profilePic = (NetworkImageView) itemView.findViewById(R.id.profilePic);
feedImageView = (TimeLineImageView) itemView.findViewById(R.id.feedImage1);
imageLike = (ImageView) itemView.findViewById(R.id.imgLike);
txtLike = (TextView) itemView.findViewById(R.id.txtLike);
txtComment = (TextView) itemView.findViewById(R.id.txtComment);
txtCommentLabel = (TextView) itemView.findViewById(R.id.txtCommentLabel);
}
}
最佳答案
添加新提要时，您必须通知 ListView 上的数据集发生更改，因此您可以执行两件事:
- 在输入新提要时创建一个新的
TimeLineItem 项，并向其中添加新项，如下所示:
`
item.setStatus("New Status");
item.setProfilePic("New Profile Pic");
item.setTimeStamp("New TimeStamp");
item.setIsLike("True");
item.setTotalLikes("1000");
item.setTotalComment("2");
`
然后使用 timeLineItems.add(item) 将新项目添加到 ArrayList 并调用 adapter.notifyDataSetChanged(); 将其显示在 view 中。
2. 再次创建 Volley 请求，它会自动执行，但这比上面的示例慢。
如果您有任何疑问，请询问。
关于java - 如何在不滚动或刷新 View 的情况下同时向recycleview添加新的提要？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45606608/