iOS native module: TiUIImageViewProxy is not exported from TitaniumKit and thus cannot be extended

[grebulon]

I have searched and made sure there are no existing issues for the issue I am filing

• I have searched the existing issues

Description

I'm developing a native module that implements ImageView with gif support. My initial intention was to either inherit from TiUIImageViewProxy and TiUIImageView and just add a gif property, or swizzle setImage_: to identify and support gifs.
Turns out that these classes are not exported from TitaniumKit and therefore cannot be used.
Instead of just inheriting (like I do for Android), I need to copy the entire source code to my native module.
Note that I also need to add functionality to Label/TextField and to ListView (which is more complicated) so I will have to copy that code too.

Note

1. I know that the Titanium classes are linked by the xcode project directly to the app and are outside the kit. What I don't know is how to link and inherit in a native module. In Android, all the classes are in the aar unlike iOS.
2. As an example, see: the TiGIF module which does this by adding a setGif_: method to TiUIImageView by swizzling it.

Solution

I'd appreciate it if you export all those classes directly from TitaniumKit. It will make everything much easier.
Or perhaps there's a simpler solution?

Alternatives

I considered modifying and building the TitaniumKit myself, but this will make it difficult to keep up with new versions because I will have to manually merge the code with every release.

Platforms

iOS

[hbugdoll]

Does https://github.com/mpociot/TiImageFromGIF help?

[grebulon]

No. It does the same.
The thing is that it's not only gif support. There are other things I need in other classes/proxies.
It's a general problem in native module development - how to extend Titanium classes that are not in the Titanium Kit?

[hbugdoll]

Sorry, I still don't quite get it.

You can use a Category as in e.g. TiUIImageView (GIF)
or you can use a Class Extension as in e.g. BencodingBlurBasicBlurViewProxy : TiUIImageViewProxy.

Edit: Oh, TiGIF and Ti.BlurView are from the pre-TitaniumKit era.

[grebulon]

If you try to build Ti.BlurView with Titanium 13, you get errors like:
BencodingBlurGPUBlurImageView.h:11:44: error: cannot find interface declaration for 'TiUIImageView', superclass of 'BencodingBlurGPUBlurImageView'
or
BencodingBlurBasicBlurViewProxy.h:10:46: error: cannot find interface declaration for 'TiUIImageViewProxy', superclass of 'BencodingBlurBasicBlurViewProxy'
This happens even though #import "TiUIImageViewProxy.h" is there. I couldn't find a solution to this.

[m1ga]

Interesting question. Marc extended a label for me once and if I see it correctly he used the whole tiuilabel file in https://github.com/mbender74/ti.labelextension-ios/blob/master/ios/Classes/TiUILabel%2BExtended.m too.
so with your question we could just extend the existing file which would make it a lot cleaner.

Maybe this part in the BlurView was responsible to make it work:
https://github.com/hansemannn/Ti.BlurView/blob/master/iOS/titanium.xcconfig#L14-L16
in the current modules it will just use
https://github.com/tidev/titanium-sdk/blob/main/iphone/templates/module/default/template/ios/titanium.xcconfig.ejs#L13
that said: I wasn't able to build that repo.

Or you have to add the source folders in Xcode somehow? Just a few guesses here I don't know anything about the inheritance in objc 😄

[grebulon]

The kind of swizzling like in TiUILabel+Extended.m sometimes work and sometimes not - I'm not sure how. The TiGIF module does work, even though I couldn't manage to do it with a modern module project (ti create).

As for adding paths to HEADER_SEARCH_PATHS - this doesn't help. The compiler doesn't fail with "error: 'TiUIImageViewProxy.h' file not found", it fails becase for some reason it cannot find interface declaration for 'TiUIImageViewProxy'.

[hbugdoll]

If you try to build Ti.BlurView with Titanium 13, you get errors like:
BencodingBlurGPUBlurImageView.h:11:44: error: cannot find interface declaration for 'TiUIImageView', superclass of 'BencodingBlurGPUBlurImageView'
or
BencodingBlurBasicBlurViewProxy.h:10:46: error: cannot find interface declaration for 'TiUIImageViewProxy', superclass of 'BencodingBlurBasicBlurViewProxy'
This happens even though #import "TiUIImageViewProxy.h" is there. I couldn't find a solution to this.

At first, I didn't want to believe it, but you're right!
I just tested it with a fresh new Titanium ObjC module and saw the
error: cannot find interface declaration for ....

In my opinion, the problem is not that TiUIImageViewProxy & Co. are not exported from TitaniumKit, but rather an error in xcconfig resp. HEADER_SEARCH_PATHS or the build system.

PS: TiGIF and Ti.BlurView are from the pre-TitaniumKit era – I didn't check the release date.

[grebulon]

I don't think it's related to HEADER_SEARCH_PATHS. I tried to play with it, adding all the paths directly but couldn't make it work.

BlurView is difficult to build because it reliies on the [ancient] prebuilt libGPUImage.a which needs to be rebuilt separately with modern xcodebuild and with support for arm64.

There's another possibly unrelated thing - the Titanium proxies are built with MRC while the native modules are ARC. I don't know what will happen if you inherit from MRC objects and fiddle with their properties in ARC code.

[hbugdoll]

I don't think it's related to HEADER_SEARCH_PATHS. I tried to play with it, adding all the paths directly but couldn't make it work.

I checked it again too. The path "$(TITANIUM_SDK)/iphone/include" is right, the headers there then redirect to the "original" headers in .../iphone/Classes.

There's another possibly unrelated thing - the Titanium proxies are built with MRC

Not all, see compiler flag -fobjc-arc in e.g.

titanium-sdk/iphone/iphone/Titanium.xcodeproj/project.pbxproj

Line 29 in 5725831

197EC88C2199730800F5A077 /* TiMediaAudioPlayerProxy.m in Sources */ = {isa = PBXBuildFile; fileRef = 24CA8ABE111161FD0084E2DE /* TiMediaAudioPlayerProxy.m */; settings = {COMPILER_FLAGS = "-fobjc-arc"; }; };

... but most.

while the native modules are ARC. I don't know what will happen if you inherit from MRC objects and fiddle with their properties in ARC code.

Good point. One have to deal with __bridge, __bridge_retained and __bridge_transfer to control the object ownership.
But I have no experience with that.

[hbugdoll]

@m1ga Thanks for the hint to ti.labelextension-ios.

It was due to the TI_SYMBOL_MACROS!

In regard of error: cannot find interface declaration for TiUIImageViewProxy the symbol USE_TI_UIIMAGEVIEW has to be defined. Without there is no TiUIImageViewProxy 🙈:

titanium-sdk/iphone/Classes/TiUIImageViewProxy.h

Lines 7 to 12 in 5725831

	#ifdef USE_TI_UIIMAGEVIEW
	#import <TitaniumKit/ImageLoader.h>
	#import <TitaniumKit/TiViewProxy.h>
	@interface TiUIImageViewProxy : TiViewProxy <ImageLoaderDelegate> {

Same for TiUIImageView.

Defining TI_SYMBOL_MACROS = $(inherited) USE_TI_UIIMAGEVIEW in module.xcconfig or titanium.xcconfig has no effect for me. Defining inside the header via #define USE_TI_UIIMAGEVIEW brought success.

Edit: @hansemannn does it globally for the module in the precompiled header .pch, see https://github.com/hansemannn/titanium-context-menu/blob/main/TiContextmenu_Prefix.pch

---

Category example:

TiUIImageViewProxy+GIF.h:

#define USE_TI_UIIMAGEVIEW
#import "TiUIImageViewProxy.h"

@interface TiUIImageViewProxy (GIF)

@end

TiUIImageViewProxy+GIF.m:

#import "TiUIImageViewProxy+GIF.h"

@implementation TiUIImageViewProxy (GIF)

@end

Class Extension example:

MyImageViewProxy.h:

#define USE_TI_UIIMAGEVIEW
#import "TiUIImageViewProxy.h"

@interface MyImageViewProxy : TiUIImageViewProxy

@end

MyImageViewProxy.m:

#import "MyImageViewProxy.h"

@implementation MyImageViewProxy

@end

---

Note that I also need to add functionality to Label/TextField and to ListView (which is more complicated) so I will have to copy that code too.

The other symbols for your needs are:

• USE_TI_UILABEL for TiUILabel & TiUILabelProxy
• USE_TI_UITEXTFIELD for TiUITextField & TiUITextFieldProxy
• USE_TI_UILISTVIEW for TiUIListView & TiUIListViewProxy

[alexlarocca]

I'm in the same situation. I'd like to extend TiUITextArea and implement the following function. It allows to add custom actions to the popup menu that appears when text is selected (in addition to standard actions such as copy).

https://developer.apple.com/documentation/uikit/uitextviewdelegate/textview(_:editmenufortextinranges:suggestedactions:)

I created a simple module (just a PoC). Unfortunately it needs to reimplement all the features a TextArea has (too bad and I'm not experienced enough in Swift/Objc).

import TitaniumKit
import UIKit

class TiTextviewView: TiUIView, UITextViewDelegate {
  private let textView: UITextView
  private var customActions: [String] = []
    
  override init(frame: CGRect) {
      self.textView = UITextView(frame: .zero)
    super.init(frame: frame)
    initialize()
  }

  required init?(coder: NSCoder) {
    self.textView = UITextView(frame: .zero)
    super.init(coder: coder)
    initialize()
  }

  convenience init(proxy: TiViewProxy) {
    self.init(frame: .zero)
    self.proxy = proxy
  }

  private func initialize() {
    textView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    textView.delegate = self
    textView.backgroundColor = .clear
    textView.font = UIFont.systemFont(ofSize: 16)
    textView.textColor = .black
    textView.isEditable = true
    self.addSubview(textView)
  }

  override func frameSizeChanged(_ frame: CGRect, bounds: CGRect) {
    super.frameSizeChanged(frame, bounds: bounds)
    textView.frame = bounds
  }

  // MARK: - API pubblica

  var text: String? {
    return textView.text
  }

  func setText(_ value: String?) {
    textView.text = value
  }
    
  func setEditable(_ value: Any?) {
    textView.isEditable = TiUtils.boolValue(value, def: true)
  }
  
  func setFontSize(_ value: Any?) {
    let fontSize = TiUtils.floatValue(value, def: 16)
    textView.font = UIFont.systemFont(ofSize: fontSize)
  }

    func setCustomActions(_ value: Any?) {
        guard let items = value as? [String] else {
          customActions = []
          return
        }
         
        customActions = items
  }
    
  // MARK: UITextViewDelegate

  func textViewDidChange(_ textView: UITextView) {
    proxy?.fireEvent("change", with: [
      "value": textView.text ?? ""
    ])
  }

    
    func textView(_ textView: UITextView, editMenuForTextIn range: NSRange, suggestedActions: [UIMenuElement]) -> UIMenu? {
        var additionalActions: [UIMenuElement] = []

        if range.length > 0 {
            for customAction in customActions {
                let action = UIAction(title: customAction) { [self] action in
                    self.proxy?.fireEvent("customaction", with: [
                      "value": customAction,
                      "range": [
                        "location": range.location,
                        "length": range.length
                      ]
                    ])
                }
                additionalActions.append(action)
            }
       }
        
        return UIMenu(children: additionalActions + suggestedActions)
    }
    
}

[grebulon]

It was due to the TI_SYMBOL_MACROS!

In regard of error: cannot find interface declaration for TiUIImageViewProxy the symbol USE_TI_UIIMAGEVIEW has to be defined. Without there is no TiUIImageViewProxy 🙈:

OH! Yes.
Thank you very very much! I should have seen this...

[alexlarocca]

So is it finally possible to extend directly a class like TiUIImageView or TiUITextArea?
In this case what are the necessary steps?
Can it be done in swift too or just in objc?

Having a template/sample project should be great.

Thanks