I'm using JSQMessageViewController for a simple chat app I'm building, and since I'm new in Swift and iOS development in general, I need some help on how to achieve this:
I want to add a timestamp inside the chat bubble. I read that I need to change some related xib files, but I'm not quite sure how to do that.
I found this, and marcuschoong's comment gets pretty close, but I'm not sure how to find these xibs' classes, and how to connect the IBOutlets to that class (I don't have any experience in Objective C either). I need the timestamp for both incoming and outgoing messages. Any help would be appreciated!
There are 2 xib files depending on the type of message, incoming or outgoing:
JSQMessageCollectionViewCellIncoming.xib
JSQMessageCollectionViewCellOutgoing.xib
Both have the same structure: avatar, bubble container, cellTopLabel, cellBottomLabel...
In your case, you can move either cellTopLabel or cellBottomLabel into the bubble container (and adjust their constraints). If you use cellBottomLabel, you'll need to modify the following method in order to show the timestamp for every message (by default the timestamp is only displayed every 3 messages, "indexPath.item % 3"):
- (NSAttributedString *)collectionView:(JSQMessagesCollectionView *)collectionView attributedTextForCellBottomLabelAtIndexPath:(NSIndexPath *)indexPath
{
JSQMessage *message = messages[indexPath.item];
return [[JSQMessagesTimestampFormatter sharedFormatter] attributedTimestampForDate:message.date];
}
Related
OK, I have been at this for a while ...
I am trying to track when user changes input languages from Language Bar.
I have a Text Service DLL - modeled from MSDN and WinSDK samples - that registers fine, and I can use the interfaces ITfActiveLanguageProfileNotifySink & ITfLanguageProfileNotifySink and see those events just fine.
I also have finally realized that when I change languages these events occur for the application/process that currently has focus.
What I need to do is to simply have these events able to callback to my own application, when it has the focus. I know I am missing something.
Any help here is appreciated.
Thanks.
I did some double-checking, and you should be able to create a thread manager object without implementing ITextStoreACP so long as you don't call ITfThreadMgr::Activate.
So, the code should look like:
HRESULT hr = CoInitialize(NULL);
if (SUCCEEDED(hr))
{
ITfThreadMgr* pThreadMgr(NULL);
hr = CoCreateInstance(CLSID_TF_ThreadMgr, NULL, CLSCTX_INPROC_SERVER, IID_ITfThreadMgr, (LPVOID*) &pThreadMgr);
if (SUCCEEDED(hr))
{
ITfSource *pSource;
hr = pThreadMgr->QueryInterface(IID_ITfSource, (LPVOID*)&pSource);
if(SUCCEEDED(hr))
{
hr = pSource->AdviseSink(IID_ITfActiveLanguageProfileNotifySink,
(ITfActiveLanguageProfileNotifySink*)this,
&m_dwCookie);
pSource->Release();
}
}
}
Alternatively, you can use ITfLanguageProfileNotifySink - this interface is driven from the ItfInputProcessorProfiles object instead of ItfThreadMgr. There's a sample of how to set it up on the MSDN page for ItfLanguageProfileNotifySink.
For both objects, you need to keep the source object (ITfThreadMgr or ITfInputProcessorProfiles) as well as the sink object (what you implement) alive until your application exits.
Before your application exits, you need to remove the sink from the source object using ITfSource::UnadviseSink, and then release the source object (using Release). (You don't need to keep the ItfSource interface alive for the life of your application, though.)
I guess I'll start by saying I am very new to B4A, and to programming in general. I have some very basic java and html exp. but that's it. I do not have any basic4ppc or really any IDE experience. Been using B4A for a few days now and can't get over the hump. Here are my noob questions:
Does having many activities (20-30+) slow down the app? Is there a downside to having a lot of activities?
I can't figure out how to scroll in the designer. I am trying to make a screen that has 25 buttons down in 1 column. However I can't scroll down to add more buttons below. I am able to add buttons programmically and in the fashion that I want (using a for loop), but is it normal to create views at runtime like this?
How do you ensure your app looks the same across all devices? Tablets? I have a scroll view that fits perfect in the emulator, but on my phone (droid x), the bottom of the scroll view is not stretched to the bottom of the phone. I use the code: scvScreen1.Initialize(100%y). Is that not right?
I have a Email screen in which is comprised of an edittext and a Send button, so that the users can send me questions from the app. However the Send button gives me this error on the 'URI =' line: "LastException java.lang.NumberFormatException: mailto:" here is the code:
Sub btnSendEmail_Click
Dim Uri As String
Uri="mailto:me#gmail.com?subject=Test Email&body=" + edtHelpEmail.Text
Dim Intent1 As Intent
Intent1.Initialize(Intent1.ACTION_VIEW,Uri
StartActivity(Intent1)
End Sub
Or is there another way to open the device's default email program?
Regarding last question, how do I copy error messages to clipboard?? I selected the red error message on the bottom right of the IDE and tried ctrl-c, but didn't work.
In B4A, what is a good method of storing persistent data? All I really need to store are some strings. Nothing fancy. These strings are to be stored locally. AI made this easy by using TinyDB.
When using the designer, how do you ensure your views are centered on all devices? For instance, I have a screen that has several rows made up of: (label, edittext, label). And I want each row to be center aligned. Do I do this programmically? I'm thinking I would have to append each row of (label, edittext, label) to a panel, then in the code center the panel. Is this correct?
That's all I got for now, but I'm sure there will be plenty more questions later.
1) The whole idea of android is to small components i.e. Apps working together, so no need to worry about opening lots of activities. Memory is very well managed behind the scenes in Android.
2) Sure. That sounds fine to me. Use the Layout designer as much as you can and then add the dynamic stuff later. It's all about striking a balance between the size of your code and the number of activities.
3) In the Designer there's an option called 'Send to UI Cloud'. This compares your app over multiple screen sizes. You can also scale your design and programmatically resize specific controls within your app in the Activity_Create Lifecycle
4) What you're doing is almost correct. I corrected your code:
Sub MailTo(StrAddress As String, StrSubject As String, StrBody As String)
Dim StrMethod As String = "Sub MailTo(StrAddress As String, StrSubject As String, StrBody As String)"
Try
Dim StrUri As String
StrUri = "mailto:" & StrAddress & "?subject=" & StrSubject & "&body=" & StrBody
Dim Intent As Intent
Intent.Initialize(Intent.ACTION_VIEW, StrUri)
StartActivity(Intent)
Catch
If BlnLoudExceptions Then CdException.Show(StrClass, StrMethod, LastException)
End Try
End Sub
I tend to have a code module called CdIntent.bas for these functions as it both keeps the project organised and makes it easier to implement the same functionality across projects.
Then to call you would use
CdIntent.MailTo("me#yes.no", "Subject!", "Body!")
5) I have a file called CdException.bas
Sub Process_Globals
'These global variables will be declared once when the application starts.
'These variables can be accessed from all modules.
End Sub
Sub Show(StrClass As String, StrMethod As String, Ex As Exception)
LogColor("Exception: " & Ex.Message & " - Class: " & StrClass & " - Method: " & StrMethod, Colors.Magenta)
End Sub
and then wrap functions in the following way:
Sub FunctionName(...Parameters...) as Int
Dim StrMethod As String = "Sub Sleep(LngMilliseconds As Long)"
Dim IntResult As Int = 0
Try
[code here inc. IntResult = ???]
Catch
If BlnLoudExceptions Then CdException.Show(StrClass, StrMethod, LastException)
End Try
Return IntResult
End Sub
BlnLoudExceptions is a global boolean that you'd declare in
Process_Globals that you can switch on an off exception logs.
StrClass is a global String that you'd declare in Process_Globals
that contains the name of the class e.g. "CdIntent.bas"
The exceptions then appear in magenta in the log screen along with the method name and class in which they occurred allowing you to home in on them.
6) I have a table in an SQLLite database called TabletSettings, which has two TEXT colums called 'Name' and 'Value'. It works well and gets you into a (what I think is a) good habit of always having a database available to your app from the get-go.
7) I'll get back to you on this as I haven't done this before.
Until then, the following thread will help you in the B4A forum http://www.basic4ppc.com/android/forum/threads/convert-integer-to-dip.18800/
I agree with Jim's point but will attempt to answer 1.
I'm new to android myself but as I understand it activities on the whole are only running when active. Unless you are using the app to continuously do something there is only one activity at a time. The number of activities is likely to affect the ram available more than anything. Lastly it might be worth walking first rather than running so to speak but trying a single and then add multiple activities.
You could try adding a ListView or ScrollView where the items are the buttons, this seems to be the std way of doing things otherwise a tabbed view.
I have searched throughout SO on this topic for iPhone and everything points to the WWDC 2010 coverage, so yes I'm aware of that. But can anyone point me to a more detailed resource from where I can learn how to build a robust system for presenting different user interfaces on an app depending on the data that I'm presenting? I am fetching the data in a JSON format and my UI needs to vary depending on what I get out of the JSON parser.
Any books or online resources that give a detailed look into this topic?
Thanks!
I recently had the same issue in one of my apps (navigation style) and the way I solved it is fairly simple.
I had a user_type flag in my JSON response, and depending on that flag I would push a different view controller.
For example, given my JSON response is stored in a NSMutableDictionary called "response"
if ([response objectForKey:#"account_type"] == 1) {
/*
initialize user_type 1 viewController
*/
[self.navigationController pushViewController:userType1ViewController animated:YES];
else if ([response objectForKey:#"account_type"] == 2) {
/*
initialize user_type 2 viewController
*/
[self.navigationController pushViewController:userType2ViewController animated:YES];
}
You can have as many different user_types as you want.
Editing after clarification in comments
You will likely be manually drawing these views.
I would subclass UIView for each of the different question types you have listed (including properties for common elements like question title, choices, etc). Assuming that questions with the same question type will have the same layout.
Then you can cycle through your JSON response (once it's in an array or dictionary) and lay it out.
If it's a multiple choice question, make a new multipleChoiceQuestion view, add its properties, then addSubview to the main feed view. Then, for your next view, you will need to set the frame to be:
nextQuestion.frame = CGRectMake(0, 0 + firstQuestion.frame.size.height, height, width);
This will ensure that your second question is drawn right below the first question.
I need to calculate words per minute while typing in textfield. It is typing speed calculator and it provides user text need to be typed in the lable above textfield. Please give me some idea how to get started and what events to use.
Thanks you.
UITextField lets you set a delegate implementing UITextFieldDelegate. That object will be sent textField:shouldChangeCharactersInRange:replacementString: for each edit the user does (for example entering a char).
In there you can implement your logic - saving the timestamp of the first entry, comparing each entry against the correct string, and then, when the entire string has been entered by the user, dividing the number of words with the spent time.
I'm creating an iPhone app that will pull data down from a Web API, including email addresses. I'd like to display an image associated with each email address in table cells, so I'm searching the Address Book for images and falling back on a default if the email address isn't in the book. This works great, but I have a few concerns:
Performance: The recipes I've found for looking for an address book record by Email address (or phone number) are reportedly rather slow. The reason for this is that one must iterate over every address book record, and for each one that has an image, iterate over all email addresses to find a match. This can be time-consuming for a large address book, of course.
Table Cells: So I thought I'd gather up all the email addresses for which I need to find images and find them all at once. This way I iterate through the book only once for all addresses. But this doesn't work well for table cells, where each cell corresponds to a single email address. I'd either have to gather all the images before displaying any cells (potentially slow), or have each cell look up each image as it loads (even slower, as I'd need to iterate through the book to find a match for each email address).
Asynchronous Lookup: So then I thought I'd look them up in bulk, but asynchronously, using NSInvocationOperation. For each image found in AddressBook, I'd save a thumbnail in the app sandbox. Then each cell could just reference this file and show the default if it doesn't exist (because it's not in the book or hasn't yet been found). If the image is later found in the asynchronous lookup, the next time the image needs to be displayed it would suddenly appear. This might work well for periodic regeneration of images (for when images have been changed in the address book, for example). But then for any given instance of my app, an image may not actually show up for a while.
Asynchronous Table Cell Lookup: Ideally, I'd use something like markjnet's asynchronous table cell updating to update table cells with an image once it has been downloaded. But for this to work, I'd have to spin off an NSInvocationOperation job for each cell as it's displayed and if the cached icon is missing from the sandbox. But then we're back to inefficiently iterating through the entire address book for each one—and that can be a lot of them if you've just downloaded a whole bunch of new email addresses.
So my question is: How do others do this? I was fiddling with Tweetie2, and it looks like it updates displayed table cells asynchronously. I assume it's sending a separate HTTP request for every image it needs. If so, I imagine that searching the local address book by email address isn't any less efficient, so maybe that's the best approach? Just not worry about the performance issues associated with searching the address book?
If so, is saving a thumbnail image in the sandbox the best approach to caching? And if I wanted to create a new job to update all the thumbnails with any changes in the address book say once a day, what's the best approach to doing so?
How do the rest of you solve this sort of problem? Suggestions would be much appreciated!
Regardless of what strategy you use for the actual caching of images, I would only make one pass through the Address Book data each time you get a batch of email addresses, if possible. (And yes, I would do this asynchronously.)
Create an NSMutableDictionary which will serve as your in-memory cache for search results. Initialize this dictionary with each email address from the download as a key, with a sentinel as that key's value (such as [NSNull null]).
Next, iterate through each ABRecordRef in the Address Book, calling ABRecordCopyValue(record, kABPersonEmailProperty) and looping through the results in each ABMultiValue that is returned. If any of the email addresses are keys in your cache, set [NSNumber numberWithInt:ABRecordGetRecordId(record)] as the value of that key in your dictionary.
Using this dictionary as a lookup index, you can quickly obtain the images of ABRecordRefs for only the email addresses that you are currently displaying in your table view given the user's current scroll position, as suggested in hoopjones's answer. You can add an address book change listener to invalidate your cache, trigger another indexing operation, and then update the view, if your application needs that level of "up-to-date-ness".
I'd use the last method you listed (Asynchronous Table Cell Lookup) but only look images for the current records being displayed. I overload the UIScrollViewDelegate methods to find out when a user has stopped scrolling, and then only start making requests for the current visible cells.
Something like this (this is slightly modified from a tutorial I found on the web which I can't find now, apologies for not citing the author) :
- (void)loadContentForVisibleCells
{
NSArray *cells = [self.table visibleCells];
[cells retain];
for (int i = 0; i < [cells count]; i++)
{
// Go through each cell in the array and call its loadContent method if it responds to it.
AddressRecordTableCell *addressTableCell = (AddressRecordTableCell *)[[cells objectAtIndex: i] retain];
[addressTableCell loadImage];
[addressTableCell release];
addressTableCell = nil;
}
[cells release];
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView;
{
// Method is called when the decelerating comes to a stop.
// Pass visible cells to the cell loading function. If possible change
// scrollView to a pointer to your table cell to avoid compiler warnings
[self loadContentForVisibleCells];
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate;
{
if (!decelerate)
{
[self loadContentForVisibleCells];
}
}
Once you know what address records are currently visible, just doing a search for those (5 -7 records probably) will be lightning fast. Once you grab the image, just cache it in a dictionary so that you don't have to redo the request for the image later.
You seem to try to implement lazy images loading in UITableView.
there's a good example from Apple, I'm referencing it here :
Lazy load images in UITableView
FYI, I've released a free, powerful, and easy library for doing asynchronous image loading and fast file caching: HJ Managed Objects
http://www.markj.net/asynchronous-loading-caching-images-iphone-hjobjman/