FLTK在按钮释放时从输入中获取价值 [英] FLTK Getting value from input on button release

问题描述

我已经完成了一些教程，当我按下按钮时可以打印一些内容，但是我不知道如何存储插入到输入小部件中的值，将用户购买到变量中供我使用.我是C ++和FLTK的新手，所以不确定是否可以使用Java扫描程序之类的简单工具.我假设您将使用类似 var = input-value(); 的方法，但是我不知道如何在回调中使用它，因为它们仅采用某些参数.如:

I've done some tutorials and can get some things to print when I press a button but I cannot figure out how to store a value that is inserted into an input widget buy the user into a variable for me to use. I'm new to C++ and FLTK so I'm not sure if there's a simple thing like a Java Scanner to use. I'm assuming you would use something like var=input-value(); but I don't know how to use it within the callbacks since they only take certain parameters. Such as:

  Fl_Button *butts[2];

  static void Button_cb(Fl_Widget * w, void* data){

  Fl_Button *b = (Fl_Button*)w;
  fprintf(stderr, "Button '%s' was %s\n", b->label(), b->value() ? "Pushed" : "Released");

}

我不能只更换打印线以使其正常工作.我没有找到并经过的所有教程都对此进行了解释.

I can't just replace the print line for it to work. None of the tutorials I found and went through explained this.

推荐答案

您正在考虑的级别太低.只需在更高的级别上使用它即可:回调是单击操作的结尾:而不是按下或释放.

You're thinking at too low a level. Just use it at a slightly higher level: the callback is the end of the clicking operation: not the press or the release.

#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Input.H>
#include <FL/Fl_Int_Input.H>
#include <FL/Fl_Button.H>
#include <FL/Fl_Color_Chooser.H>

struct Info
{
    // The widgets
    Fl_Input* instr;
    Fl_Int_Input* inint;

    // Saved values
    char sval[40];
    int  ival;
};

// Callback for the done button
void done_cb(Fl_Widget* w, void* param)
{
    Info* input = reinterpret_cast<Info*>(param);

    // Get the values from the widgets
    strcpy (input->sval, input->instr->value());
    input->ival = atoi(input->inint->value());

    // Print the values
    printf("String value is %s\n", input->sval);
    printf("Integer value is %d\n", input->ival);
}

int main(int argc, char **argv)
{
    Info input;

    // Setup the colours
    Fl::args(argc, argv);
    Fl::get_system_colors();

    // Create the window
    Fl_Window *window = new Fl_Window(200, 150);
    int x = 50, y = 10, w = 100, h = 30;
    input.instr = new Fl_Input(x, y, w, h, "Str");
    input.instr->tooltip("String input");

    y += 35;
    input.inint = new Fl_Int_Input(x, y, w, h, "Int"); 
    input.inint->tooltip("Integer input");

    y += 35;
    Fl_Button* done = new Fl_Button(x, y, 100, h, "Done");
    done->callback(done_cb, &input); 
    window->end();

    window->show(argc, argv);
    return Fl::run();
}

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