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Simplify platform differences handling in the preferences sample

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Use an alternative and arguably simpler (at least with real-life
applications, where settings are somewhat more complex) way of handling
the differences between platforms in the preferences sample: instead of
executing completely different code under different platforms, always
update the local copy of the settings immediately and just propagate, or
not, it to the application-level settings depending on the current
platform.

This costs an extra copy of the settings object on each change, but this
shouldn't be a problem in practice, and OTOH results in using mostly the
same code under all platforms, reducing the probability of
platform-specific bugs and avoiding any code duplication between the
event handlers and TransferDataFromWindow().
This commit is contained in:
Vadim Zeitlin
2017-07-11 23:34:37 +02:00
parent 552c942a76
commit 101509eb4b
1 changed files with 38 additions and 28 deletions
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66
samples/preferences/preferences.cpp
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@@ -54,15 +54,14 @@ public:
void ShowPreferencesEditor(wxWindow* parent);
void DismissPreferencesEditor();
void UpdateSettings();
// Make them public for simplicity, we could also provide accessors, of
// course.
MySettings m_settings;
const MySettings& GetSettings() const { return m_settings; }
void UpdateSettings(const MySettings& settings);
private:
class MyFrame* m_frame;
wxScopedPtr<wxPreferencesEditor> m_prefEditor;
MySettings m_settings;
};
wxIMPLEMENT_APP(MyApp);
@@ -108,7 +107,7 @@ public:
{
// Here we should update the settings we use. As we don't actually do
// anything in this sample, just update their values shown on screen.
const MySettings& settings = wxGetApp().m_settings;
const MySettings& settings = wxGetApp().GetSettings();
m_textMarkdownSyntax->SetLabel(settings.m_useMarkdown ? "yes" : "no");
m_textSpellcheck->SetLabel(settings.m_spellcheck ? "on" : "off");
}
@@ -149,24 +148,19 @@ public:
SetSizerAndFit(sizer);
// On some platforms (OS X, GNOME), changes to preferences are applied
// immediately rather than after the OK or Apply button is pressed.
if ( wxPreferencesEditor::ShouldApplyChangesImmediately() )
{
m_useMarkdown->Bind(wxEVT_CHECKBOX,
&PrefsPageGeneralPanel::ChangedUseMarkdown,
this);
m_spellcheck->Bind(wxEVT_CHECKBOX,
&PrefsPageGeneralPanel::ChangedSpellcheck,
this);
}
m_useMarkdown->Bind(wxEVT_CHECKBOX,
&PrefsPageGeneralPanel::ChangedUseMarkdown,
this);
m_spellcheck->Bind(wxEVT_CHECKBOX,
&PrefsPageGeneralPanel::ChangedSpellcheck,
this);
}
virtual bool TransferDataToWindow()
{
const MySettings& settings = wxGetApp().m_settings;
m_useMarkdown->SetValue(settings.m_useMarkdown);
m_spellcheck->SetValue(settings.m_spellcheck);
m_settingsCurrent = wxGetApp().GetSettings();
m_useMarkdown->SetValue(m_settingsCurrent.m_useMarkdown);
m_spellcheck->SetValue(m_settingsCurrent.m_spellcheck);
return true;
}
@@ -174,28 +168,43 @@ public:
{
// Called on platforms with modal preferences dialog to save and apply
// the changes.
MySettings& settings = wxGetApp().m_settings;
settings.m_useMarkdown = m_useMarkdown->GetValue();
settings.m_spellcheck = m_spellcheck->GetValue();
wxGetApp().UpdateSettings();
wxGetApp().UpdateSettings(m_settingsCurrent);
return true;
}
private:
void UpdateSettingsIfNecessary()
{
// On some platforms (OS X, GNOME), changes to preferences are applied
// immediately rather than after the OK or Apply button is pressed, so
// we need to take them into account as soon as they happen. On others
// (MSW), we need to wait until the changes are accepted by the user by
// pressing the "OK" button. To reuse the same code for both cases, we
// always update m_settingsCurrent object under all platforms, but only
// update the real application settings if necessary here.
if ( wxPreferencesEditor::ShouldApplyChangesImmediately() )
{
wxGetApp().UpdateSettings(m_settingsCurrent);
}
}
void ChangedUseMarkdown(wxCommandEvent& e)
{
wxGetApp().m_settings.m_useMarkdown = e.IsChecked();
wxGetApp().UpdateSettings();
m_settingsCurrent.m_useMarkdown = e.IsChecked();
UpdateSettingsIfNecessary();
}
void ChangedSpellcheck(wxCommandEvent& e)
{
wxGetApp().m_settings.m_spellcheck = e.IsChecked();
wxGetApp().UpdateSettings();
m_settingsCurrent.m_spellcheck = e.IsChecked();
UpdateSettingsIfNecessary();
}
wxCheckBox *m_useMarkdown;
wxCheckBox *m_spellcheck;
// Settings corresponding to the current values in this dialog.
MySettings m_settingsCurrent;
};
class PrefsPageGeneral : public wxStockPreferencesPage
@@ -304,7 +313,8 @@ void MyApp::DismissPreferencesEditor()
m_prefEditor->Dismiss();
}
void MyApp::UpdateSettings()
void MyApp::UpdateSettings(const MySettings& settings)
{
m_settings = settings;
m_frame->UpdateSettings();
}