Boolean Checkbox Change Tracking Example

Embarcadero

vor 2 Jahren

Update checkbox boolean cross platform example

The Update Checkbox Demo is the perfect way to show how Live Bindings can be used to update a label when a checkbox changes. It is a cross-platform application that has been built in Delphi using a single code base and single UI for Android, iOS, macOS, Windows, and Linux. This makes it the perfect tool for anyone who wants to learn how to build cross-platform applications using Live Bindings.

Download the full cross-platform update checkbox demo source code on Github.

This demo is part of over 100 cross-platform demos with everything from camera demos to emoji demos and painting demos.

Inhaltsverzeichnis

What is a checkbox in software development?

Checkboxes are a type of input element in software development that allows the user to select multiple options from a list. These options are typically presented as a list of checkboxes, each with a corresponding label. Checkboxes are often used in forms, such as surveys or sign-up forms, as they allow the user to select multiple options without having to enter each one individually. When checkboxes are used in this way, they are often referred to as “multiple-choice” or “select all that apply” inputs. In addition to forms, checkboxes are also commonly used in menus and other interfaces where multiple selection is desired. Checkboxes are usually accompanied by labels that describe the option or options that can be selected. For example, a checkbox labeled “I agree” might be used to indicate that the user agrees to the terms and conditions of a website. Checkboxes can also be programmed to perform certain actions when selected, such as opening a new window or changing the display mode of an interface.

What is a boolean in software development?

A boolean is a data type that can have one of two values, usually represented by the integers 0 and 1. In software development, boolean values are often used to represent the truth or falsehood of a statement. For example, a boolean variable might be used to keep track of whether a user is logged in or not. When the user logs in, the variable would be set to true; when the user logs out, the variable would be set to false. Boolean values can also be used in mathematical operations. For example, the boolean AND operation takes two boolean values and returns true if both values are true; otherwise, it returns false. Similarly, the boolean OR operation takes two boolean values and returns true if either value is true; if both values are false, it returns false. Boolean values are an important part of many programming languages and are commonly used in software development.

Screenshot

What does the source code of the checkbox demo look like?

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Param,
  FireDAC.Stan.Error, FireDAC.DatS, FireDAC.Phys.Intf, FireDAC.DApt.Intf,
  FireDAC.Stan.StorageBin, Data.Bind.EngExt, Fmx.Bind.DBEngExt, System.Rtti,
  System.Bindings.Outputs, Fmx.Bind.Editors, Data.Bind.Components, FMX.StdCtrls,
  Data.Bind.DBScope, Data.DB, FireDAC.Comp.DataSet,
  FireDAC.Comp.Client, FMX.Effects, FMX.Controls.Presentation;

type
  TForm1 = class(TForm)
    MaterialOxfordBlueSB: TStyleBook;
    ToolBar1: TToolBar;
    ShadowEffect4: TShadowEffect;
    Label1: TLabel;
    Label2: TLabel;
<strong>    FDMemTable1: TFDMemTable;
    BindSourceDB1: TBindSourceDB;
    BindingsList1: TBindingsList;
    CheckBox1: TCheckBox;
    LinkPropertyToFieldText: TLinkPropertyToField;
    LinkControlToField1: TLinkControlToField;</strong>
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

end.

unit Unit1;

interface

uses

System.SysUtils, System.Types, System.UITypes, System.Klassen, System.Variants,

FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,

FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Param,

FireDAC.Stan.Error, FireDAC.DatS, FireDAC.Phys.Intf, FireDAC.DApt.Intf,

FireDAC.Stan.StorageBin, Data.Bind.EngExt, Fmx.Bind.DBEngExt, System.Rtti,

System.Bindings.Outputs, Fmx.Bind.Editors, Data.Bind.Komponenten, FMX.StdCtrls,

Data.Bind.DBScope, Data.DB, FireDAC.Comp.DataSet,

FireDAC.Comp.Client, FMX.Effects, FMX.Controls.Presentation;

type

TForm1 = Klasse(TForm)

MaterialOxfordBlueSB: TStyleBook;

ToolBar1: TToolBar;

ShadowEffect4: TShadowEffect;

Label1: TLabel;

Label2: TLabel;

<strong> FDMemTable1: TFDMemTable;

BindSourceDB1: TBindSourceDB;

BindingsList1: TBindingsList;

CheckBox1: TCheckBox;

LinkPropertyToFieldText: TLinkPropertyToField;

LinkControlToField1: TLinkControlToField;</strong>

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.fmx}

end.

What does the data binding component object source code look like?

  object BindSourceDB1: TBindSourceDB
    DataSet = FDMemTable1
    ScopeMappings = &lt;&gt;
    Left = 144
    Top = 224
  end
  object BindingsList1: TBindingsList
    Methods = &lt;&gt;
    OutputConverters = &lt;&gt;
    Left = 20
    Top = 5
    object LinkPropertyToFieldText: TLinkPropertyToField
      Category = 'Quick Bindings'
      DataSource = BindSourceDB1
      FieldName = 'Value'
      Component = Label2
      ComponentProperty = 'Text'
    end
    object LinkControlToField1: TLinkControlToField
      Category = 'Quick Bindings'
      DataSource = BindSourceDB1
      FieldName = 'Value'
      Control = CheckBox1
      Track = True
    end
  end

object BindSourceDB1: TBindSourceDB

DataSet = FDMemTable1

ScopeMappings = <>

Left = 144

Top = 224

end

object BindingsList1: TBindingsList

Methods = <>

OutputConverters = <>

Left = 20

Top = 5

object LinkPropertyToFieldText: TLinkPropertyToField

Category = 'Quick Bindings'

DataSource = BindSourceDB1

FieldName = 'Value'

Component = Label2

ComponentProperty = 'Text'

end

object LinkControlToField1: TLinkControlToField

Category = 'Quick Bindings'

DataSource = BindSourceDB1

FieldName = 'Value'

Control = CheckBox1

Track = True

end

What do the data bindings look like for the boolean checkbox control?

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