Button with image

[enricovittorini]

Hello all,
be patient... I am trying to learn...

I would like to use an image as a button. Reading the documentation i did the following:

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        wxBitmap bitmap;
        bitmap.LoadFile("calc.png", wxBITMAP_TYPE_PNG); 

       wxButton* calculator = new wxButton(this, i, "", wxDefaultPosition, wxSize(20,-1));
       calculator->SetBitmap(bitmap);
       costSizer->Add(calculator);

but this is not working: no compile error, the windows is loaded but the image is not shown
What am I doing wrong?
thanks for your help!

[ONEEYEMAN]

Hi,
Are you sure the file you are loading exist?
Is loading sicceeded?
Did you call wxInitAllImageHandler() in the startup of the application?

Thank you.

[enricovittorini]

Hi, thanks for you answer. The file exists cose if I use BitMapButton it works.

I also confirm that wxInitAllImageHandler() have been added.

[enricovittorini]

I guess I found the issue: in my button definition there was no text cose i just wanted the image

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wxButton* calcultatorBtn = new wxButton(this, i, "" );

as I added a text, it started working.

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wxButton* calcultatorBtn = new wxButton(this, i, " txt" );

Now I need to figure out how to style without text. I tried:

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wxButton* calcultatorBtn = new wxButton(this, i, wxEmptyString, wxDefaultPosition, wxDefaultSize, wxBU_EXACTFIT |  wxBU_NOTEXT);

but if there is no text, it does not work!

any clue?

[ONEEYEMAN]

Hi,
If there is no text - use wxBitmapButton.

Thank you.

[enricovittorini]

I was thinking that by using the following style I was going to get a button with an image without a text. Did I misunderstood?
https://docs.wxwidgets.org/3.2/classwx_button.html

wxBU_NOTEXT:
Disables the display of the text label in the button even if it has one or its id is one of the standard stock ids with an associated label: without using this style a button which is only supposed to show a bitmap but uses a standard id would display a label too.

[enricovittorini]

Damn... think I found the issue.
the button as "i" as ID: this is because it is in a for loop and I need to set a known ID. The "i" starts at 0 and it seems wxWidgets does not like this.
If I change the value of the ID from "i" to "i+1" it works.

I think this is due to https://docs.wxwidgets.org/latest/overv ... owids.html

Finally, you can just define your own IDs. Typically this is done by using a C++ enum to automatically ensure their uniqueness. If you do this, please note that your custom IDs must be positive to avoid clashes with the automatically assigned IDs discussed above and should not have values 0 or 1, that can result in surprising behaviour under some platforms

[ONEEYEMAN]

Hi,
Why do you need an id at all? Why not use wxID_ANY?

Thank you.

[enricovittorini]

because I create a vector of objects with a for loop. In each raw I have a button.

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- unit price ; quantuty ; btn;  total
- unit price ; quantity ; btn;  total
- unit price ; quantity ; btn;  total
- unit price ; quantity ; btn;  total
...
...

every loop iteration, i put the "unit price", the "quantity" and the toal in three vectors of objects.

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vector_price.pushback(unit_price);
vector_quantity.pushback(unit_price);
vector_total.pushback(unit_price);

When i click the button that is at line 2, i know i have to get:
- vector_price.at(2)
- vector_quantity.at(2)


with these value i do a math (price * quantity * and put the result in total.at(2).

I need to know the ID of the button to understand which raw it belongs to. In this example the button of raw 2 would have ID=2

[ONEEYEMAN]

Hi,
You don't have to.
Make wxButton-derived class where you set the row to some internal variable.
When you click the button - you will know the row and will be able to get the values from that row of text controls.

This will be simpler and eliminate the need of keeping the id assignments.

Thank you.

[enricovittorini]

Seems a good approach.
As I am learning... Would like to get into the details of your proposal.

Let say I have a

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for (int i = 0; i< product_size; i++) { 

Code to build wxTextCtl and Buttons here

};

Event handler for the button here

If I understand correctly, I should create a class

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RawButton : Button
{
public:
int raw= NULL;

}

What I do not understand is how to her the value of the raw variable in the event handles.

Would you help?

Thanks

[enricovittorini]

I am trying.....

Defined the following class RawButton:

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class RawButton : public wxButton
{
public: 

	int rawBtn = NULL;

	RawButton(int rawnumber, wxWindow* parent, wxWindowID id, wxString wxEmptyString, wxPoint wxDefaultPosition, wxSize wxDefaultSize, long style)
		: wxButton(parent, id, wxEmptyString, wxDefaultPosition, wxDefaultSize,style) {
		rawBtn = rawnumber;

	};
	
};

in my paneli created the following button where "i" is the rawnumber:

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        m_calcultatorBtn = new RawButton(i, this, wxID_ANY, wxEmptyString, wxDefaultPosition, wxDefaultSize, wxBU_EXACTFIT | wxBORDER_NONE | wxBU_NOTEXT);
        m_calcultatorBtn->SetBitmap(*bitmap);
        costSizer->Add(m_calcultatorBtn);

and the following event handler:

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m_calcultatorBtn->Bind(wxEVT_BUTTON, [this](wxCommandEvent& evt) {OpenCalculator(&evt); });

Now, i do not know how to get the raw number in the OpenCalculator().

[doublemax]

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m_calcultatorBtn->Bind(wxEVT_BUTTON, [this](wxCommandEvent& evt) {
  RawButton *button = dynamic_cast<RawButton *>( evt.GetEventObject() );
  if( button ) {
    int a = button->rawBtn;  
    OpenCalculator(&evt);
  }
});

However, personally i think subclassing wxButton for this purpose is overkill. Using the ID is fine. If you want to make it a little more robust, use a hashmap to connect button IDs to data-row IDs.

Also, if you use hard-coded IDs, make sure they start at wxID_HIGHEST + 1

[enricovittorini]

Thanks a lot