Tuesday, October 15, 2019

FDK Version 2.0 Beta online!

Hello FDK fans!


Finally the new Version 2.0 is online. As always, you are able to order and download it with the setup application.

As we haven't done any updates is the last year, there will be a special offer:

If you're already a FDK-customer you can order an update of you Version 1.0 only for 29,95€. If you like to update to Version 2.0 (beta) there is a discount until 15.12.2019, so you get the update for only 199,- €. The normal prize is 299,- € for the update.

If you are new to my FDK the prize for new customer is 399,- €. If you like to order the FDK with a online lesson, just send me an EMail.


Greetings

Monday, October 7, 2019

MVVM for legacy Apps?

Most developer would not do this step. But what kind of refactoring you want to do?


Well, if your app is still pre-Unicode, you probably have more to think about than implementing a MVVM Pattern, isn't it? Let me take a look into my crystal ball:

One problem of your migration is: If you change one thing at one end, you break something at the other end. I assume you have no or only a few unit-tests. Your app is not testable, because all of you business logic's are in your forms and everything is using nearly every other unit? You have references all over the place and have not used one interface?

Welcome to the club.

Perhaps it is even worse and you're using (typed) Short-Strings as Var-Parameters everywhere?

So your migration is not a "one shot changes everything for good". It's more like change a little bit here and there and hope for the best. I hate to say it, but I'm doing the same for many years. Starting with old components!

I have the source, but it is really to complicate to migrate every old stuff. (And why it is working) so the best way is to do an interface wrapper and if everything is still working, I can put this in a DLL compiled with the old delphi and uses this DLL from Rio. Perhaps some time replace this with a new implementation.

So far so good. One problem is still in place, I'm not sure if really everything is still working, because I can only do some "human application tests". Wouldn't is be great if I had at least 10% unit-tests coverage of the main core stuff? How to accomplish that?

Here is the deal: Convert your app step by step to MVVM. Normally it's not so complicated, because in 99,9% every Form is one View, every Frame is one View and normally you would end up only with a 1:1 relation. Do you need a Model? In a best case scenario, yes!

A part of my #DMVVM framework would be related to do this kind of "easy" migration. But there are still some problems: No real RTTI and generics in D2007. If the framework can compiled with D2007 - possible not, but perhaps the D2007 stuff could be in a DLL.

Stay tuned...

Tuesday, October 1, 2019

FMX-Styles Update

Prior posts about FMX Styles!

Here a little update:

I changed all the SysColors zu $FF000001 and all Colors to $FF000100 then exported a list to see if these color values are used elsewhere. And yes they are...
Not the colors from the Colors tree, but from the SysColors-Tree. So I changes all "not found" colors to 000101,000102,000103,000104... and so on.

Then I compared the to exports:



So here is an update of the used SysColors:


EditStyle Selection-BrushColor and other selections using the clHighlight Color and for Focus. Like in Grids.


Funny the Grid-Lines are using clBtnFace.

The ListView is perhaps (not in the Styleviewer) using the clWindow Color for Background and ItemBackground (not confirmed). And the TEllipse is using clBtnText for Fill-Color - strange - also not confirmed.

That's it.

Monday, September 30, 2019

Did you try to design an FMX-Style?

Do you like the styles that are included or downloadable from getit?

Perhaps you have tried to design your own style with the Bitmap-Style-Designer. 

Did it work for you?

Perhaps the problem is, that the Style-Designer is more on the VCL side... Lets take a look. First create a new "Modern Windows Style". There are two color entries (Colors and SysColors) Let's set all Colors to green (Except three that are really needed) and all SysColors to Cyan except the only two that are used from here. Then ist looks like this:


If you change a color like "Window" (I did orange) the color value is not indexed to to all components, the color is copied to the components. Like:



Perhaps its a feature to be able to change this color...

Hmm and where did I already set the font- /back-colors to white / black? 



OK, some colors are not set over a color values, because the color is rendered from the bitmap.

Take a look at the edits.


Wow the Edit background is lighter, but how to set background color? It's set by this bitmap. The background of this image-part has just a  not 100% transparent Alphacolor. 



The Run-Test-Button is helpful, because you can change something and check the results... Like this:

That is colorful - but where are all there colors from? Not from the color settings - to bad! This colors are set under Listbox (but not all).

Listbox Header - two different colors - but not set with header:


If you think this is perhaps set with PlainHeader, no PlainHeader is the Teal-Group Header and of course always the Font-Color not the Color entry. It would be to easy just set PlainHeader.Text.Color := clBlack. and this property will also set the Fontcolor. The blue GroupHeader is set by GroupHeader.Text.Font.Color and BottomDetail.Text is also set with BottomDetail.Text- thats fine. DetailText is correct. PlainItem is not PlainItem. DetailText2 is not Detail it is the ItemText5 and Detail from this is set with BasicText2. Get confused?
Scroll down there is a single entry for ListBoxHeaderLabel - this is the other ListBoxHeader. The other (Black ListBoxHeader) is not set under Listbox, because this is a ToolLabel and set under ToolLabel. This is the same for the ListItemButton.Text.


And this colors?
Purple backgrounds are set with - roll drum - clBtnFace under Syscolors. This is also the color for the Splitter.


The yellow border is set under Colors - Border.
But where to set the Arc and the CornerButton? This is not set by the Bitmap...


Here comes the best part. The CornerButton is set with a gradient and the gradient has two colors.
And no - the color is not set over Color and of course not set over Font.Color the Color value hast Du be set over PARAMS! But don't forget to switch From ARGB to ABGR (Blue and Red color switch places)

This is not a complete list of problems with the colors and I did not test this colors with a real world app so far. I did not test this on all platforms. I will try to implement some kind of color - converter - post-setup for the styles... 

So stay tuned.

PS.: Here is a litte update!

Wednesday, September 18, 2019

MVVM PropertyChanged is not Component related!

What? I use many components!

ok - lets assume you have a Button on the Form and the button is labeled "Save". How do you want to handle this button? 

1.) You can use this button like a web designer and after the button is pressed you can show up some hints : "Password missing", "Email missing" or whatever. So the user can press <Save> and directly see what is missing.
2.) You can disable then Button and enable it, if every fields are filled as you expect.  This is kind of a guessing game or you must have some remarks like "*" for fields that has to be filled. The drawback is, sometimes you have to search the view for the little missing "I agree" checkbox.

In a few situations I like (1), but in most cases I use (2).

So how to handle this in the ViewModel?  PropertyChange('DisableButton')?

No, this is wrong.

You have a property at the ViewModel like:
Property CanSave : boolean read fCanSave write SetCanSave;
In the setter you can fire PropertyChange('CanSave') and every component that has to change something could be informed by this event. When a component got his PropertyChanged call it can ask the ViewModel.

SaveBTN.Enabled := fViewModel.CanSave;

ok. 

This is the same stupid thing, already mentioned in my last post. I know "you" can bind a button to an ICommand, but that is not my idea. My PropertyChange would also include the boolean so the component or better the binder can set the value directly. Of course any boolean field could be bound directly, but what if I must do a little bit more? 

One of many ways to handle this, is a simple procedure:

Binding.Bind('CanSave',Procedure(aEvent:TPropertyChangedEvent )
  begin
    if aEvent.ParamCount = 1 then
      begin
        if aEvent.Args[0].AsBoolean
          then StateImage.Bitmap.Assign(YesIMG)
          else StateImage.Bitmap.Assign(NoIMG);
      end; 
  end);

I use this approach for everything that is not working out of the box. (Implementation is currently still under consideration in some parts)

And this is the main thing. The ViewModel knows the Model (in most cases) and the View know the ViewModel. But the Model does not know the ViewModel and the ViewModel does not know then View. Perhaps the designer of the View is a different developer than the ViewModel.

Perhaps the Model has already two new fields and the ViewModel has only implemented one of these fields, but the View isn't changed at all. Everything should work fine, because there is not 1:1 relation. What should the binder do? In debug-mode it would be nice if the binder throws an exception "Property not found" and in release mode? It depends on the settings. I like the idea that every Visual Component is set to Visible := false; if the necessary property is still missing in the ViewModel, but this is up to you. How do you handle incompatibilities between the View and the ViewModel? Feel free to leave a comment!

Now, how about the Unittests?

Model is simple, just write your tests. Test for the View? Perhaps. But beside your most important Model-Tests you also want to test your ViewModel. 

Testing your ViewModel without a View must be possible, so your Testclass slips into the role of the View. By subscribing to the 'CanSave' propertychange - for example - and filling all the fields (or not for the negative test), the testclass can check if everything works as expected.

How can you test complicated behavior like the user interaction with a Grid?

Well, this may be the topic of one of my next blog posts about my #DMVVM framework.

So stay tuned.


Sunday, September 15, 2019

MVVM and mobil app development.

A big part of the MVVM Pattern is separation and binding. I don't know how you are developing you mobil apps, but in my apps, many parts, I mean more then 80%, are created "on the fly" at runtime. Sometimes the elements would be created from the content of a database, sometimes from a REST(full) Webservice and sometimes from a config or user settings.

So here comes the funny part: Imagine controls has to be created from a database. From a ButtonClick on the View, the Viewmodel calls the Model. The Model loads all the necessary information and hast to provide this information to the Viewmodel. So far so good.

If you take a closer look, every component -  like a TEdit - is some kind of View. Views are created by the composition-root, perhaps from a event of the navigation-service, perhaps from a ViewLocator  or in case of e.g. Messagedialogs, from a dialog-service. 

In this case the Viewmodel is created with a component-service to create a component from a predefined collection. Wouldn't is be great I we already had a service like this? Yes we have. My FluentCreator could be called by this service and is able to provide an easy way to create predefined  - even complex - view-structures like I've demonstrated in my scale-able calender component. 

But where is the target? The target is a container (TLayout/ListBox) on the View, but we don't have a View-reference in our ViewModel. Conclusion the View must call the component-creation-service. Not a big deal, we could create the View with this service. But how to pass all the information from the Model to the ViewModel to the View to the component-service and keep in mind, the Viewmodul has to be testable and if possible the service, too.

One problem, the possibilities of component creation are endless. We could fire a PropertyChange with some kind of string. E.g. "Create Edit_ID parent Listbox1" we could find the Listbox1 and we could create a TEdit_ID from our lookup list in our component-service. But our Viewmodel should not know "Listbox1".

Next problem is the binding. How could we create the binding to our ViewModel? There aren't any properties to bind to. We also have to create a dynamic receiver for the created components and I'm sure we have to provide some kind of database connection to the receiver.

It looks like our component-service as three parts: One for the View, one for the ViewModel and one for the Model... 

To implement an easy to use MVVM framework is not trivial, but doing everything at runtime is a step forward. Of course, there will be a way, but finding the "best" way is the tricky part.

Think about it, I would love to read your ideas on this topic.

PS.: The dynamic creation stuff is probably not mobil related, but from my point of view Desktop apps are more static these days...


Friday, September 13, 2019

VCL and FMX Styles and the Styledesigner...

I never used VCL-Styles before, because my last app for VCL is still on D2007 and we have written our own styling. 

Since XE 2, I use FMX only.

For FMX - of course - I had to use styling and the Bitmap-Styledesigner. I'm not so happy with this app. There is a QC Entry from 2018, RSP-22407, please support.

If you tried the Styledesigner there are many objects - that's fine - and PNG's for different resolution. From my point of view one big image is only helpful if you are using some kind of template for a well know graphic program. By comparing different styles you find out, that nearly every style has it's own layout. Horrible. Unfortunately, there is no guide which part of the graphic is used for which object/action. Also the Style/New creates different layouts. 

Ok, lets take it easy: Use a predefined style, save the png file, convert the colors, reload the png file, done... Isn't it? No... You have to adjust the font-colors, because this colors are set individually. Wouldn't it be nice if the colors are taken from the png?
The is a choose color under mouse tool, but you can not open the png file and at the same time choose a color. The trick is to open on object, select background and open the rectangle editor. This windows could stay open while choosing the color.

How to uses this colors at runtime? There is no Color table in the style and if you change one color, the values are set to all objects. If you want to match a TRectangle to the given style the have to chose a control and get the color from there. So if your color settings are different from the SysColors, it's difficult. I like to have more than the given SysColors like: clHelpTextColor, clWarnColor, clInfoColor. 

So how to select a color in the ObjectInspector? You can select "Red" or "clRed" but not "clMenu" or "clScrollBar". 

The Styles that are downloadable or included are - from my point of view - all to monochrome. Most dark styles are to dark (lol... perhaps, because I do not like dark-styles at all) and all of the colored- styles have only one dominant color. I like my UI uniform, but not so uniform. Colors helps you to guide the users attention. If you place some controls on a Panel / Rectangle with a different color you can show the user that these inputs are important or less important. Perhaps UserColor1, UserColor2..UserColorN would be nice.

How to get a button with an icon? You can use a button with an Icon or you can create a new entry in the object list, add an image to the "Big-Picture", select all rectangles for enabled, disabled, hot, focused. Copying a button is a piece of cake, but how to add the image? There is no build-in function. You have to take a graphic-editor to expand your png's (1x,1.5x,2x,3x) keep in mind to place your 5 images on the same spot, if not, you have to select all rectangle individually. But how? Solution: Write a tool to add Images. After your tool has created all png's you can import this images and select the rectangles. But where are the right corners? There is no grid  and if your icon has no outside Rectangle. you never find the right points (up/left,bottom/right). Wouldn't it be great if your tool could provide a config to do this selection on import of the png? And why is there no function to do this inside the Styledesigner. And why is there a big image depending on how to create and find all the right places? 

Wouldn't it be cool if you can provide single images for all functions/objects and on style-save this images got composed (with no,or less spaces) into one big png? (for each resolution)! No Rectangle selection no guessing game where to find what? Perhaps single images are not so easy to create if you are a style-artist, but is this case the Bitmap-Styledesigner should be able to export an uniform png with rectangles where to place your images. This image could be re imported, and could be striped into single images for later composing.

If you want to change the Font-Color for e.g. TabTextActiveNormal, you can open is (Font Dialog, no selection of pre-select colors) or you can change the color, but the actual color is not set in the color-dialog. So to change the color to a darker color you have to guess or you have to put in the colors for RGB. (Not with the clipboard.)

Many stuff to do... Like in RSP-22407 - I really have no time to write my own Styledesigner starting by New-FMX-Project.

Please leave a comment of your idea or if I'm totally wrong. ;-)