Animate most of the bars

When a bar is toggled visible this usually happens because the
user might want to use its functionality now. However, if bars
appear without animation or at a location the user is not
currently looking at, they might not notice that they have appeared
at all.

An animation makes it more likely that the user notices the change
and can then use the newly made visible component.

Another reason for animations for showing or hiding of components
is that it can be disorienting for users when panels or bars
suddenly appear or disappear without animation. There is no visible
movement then, so the user might not know what happened if they
didn't concentrate or blink at that moment. The newly appearing or
disappearing component might also displace other components which
can make it difficult to find what one was just looking at.

These bars animate now after this change:
- Search panel
- Filter bar
- Status bar

This is implemented by extracting the animation code from
SelectionMode::TopBar into a new abstract base class
AnimatedHeightWidget. This class is now also used in
SelectionMode::BottomBar and the animating code there was removed.

These bars are left in Dolphin that stay without animation:
- Menu bar (Would probably need to be implemented in KXmlGui)
- Tool bar (Would probably need to be implemented in KXmlGui)
- Tab bar (Needs a different appraoch because it already inherits
QTabBar and therefore can not inherit AnimatedHeightWidget)

2 files changed, 38 insertions, 23 deletions

diff --git a/src/statusbar/dolphinstatusbar.cpp b/src/statusbar/dolphinstatusbar.cpp
index 9ea0ae5aa..8e7ee5586 100644
--- a/src/statusbar/dolphinstatusbar.cpp
+++ b/src/statusbar/dolphinstatusbar.cpp
@@ -32,7 +32,7 @@ const int UpdateDelay = 50;
 }
 
 DolphinStatusBar::DolphinStatusBar(QWidget *parent)
-    : QWidget(parent)
+    : AnimatedHeightWidget(parent)
     , m_text()
     , m_defaultText()
     , m_label(nullptr)
@@ -47,16 +47,19 @@ DolphinStatusBar::DolphinStatusBar(QWidget *parent)
     , m_textTimestamp()
 {
     setProperty("_breeze_statusbar_separator", true);
+
+    QWidget *contentsContainer = prepareContentsContainer();
+
     // Initialize text label
-    m_label = new KSqueezedTextLabel(m_text, this);
+    m_label = new KSqueezedTextLabel(m_text, contentsContainer);
     m_label->setWordWrap(true);
     m_label->setTextFormat(Qt::PlainText);
 
     // Initialize zoom slider's explanatory label
-    m_zoomLabel = new KSqueezedTextLabel(i18nc("Used as a noun, i.e. 'Here is the zoom level:'", "Zoom:"), this);
+    m_zoomLabel = new KSqueezedTextLabel(i18nc("Used as a noun, i.e. 'Here is the zoom level:'", "Zoom:"), contentsContainer);
 
     // Initialize zoom widget
-    m_zoomSlider = new QSlider(Qt::Horizontal, this);
+    m_zoomSlider = new QSlider(Qt::Horizontal, contentsContainer);
     m_zoomSlider->setAccessibleName(i18n("Zoom"));
     m_zoomSlider->setAccessibleDescription(i18nc("Description for zoom-slider (accessibility)", "Sets the size of the file icons."));
     m_zoomSlider->setPageStep(1);
@@ -67,10 +70,10 @@ DolphinStatusBar::DolphinStatusBar(QWidget *parent)
     connect(m_zoomSlider, &QSlider::sliderMoved, this, &DolphinStatusBar::showZoomSliderToolTip);
 
     // Initialize space information
-    m_spaceInfo = new StatusBarSpaceInfo(this);
+    m_spaceInfo = new StatusBarSpaceInfo(contentsContainer);
 
     // Initialize progress information
-    m_stopButton = new QToolButton(this);
+    m_stopButton = new QToolButton(contentsContainer);
     m_stopButton->setIcon(QIcon::fromTheme(QStringLiteral("process-stop")));
     m_stopButton->setAccessibleName(i18n("Stop"));
     m_stopButton->setAutoRaise(true);
@@ -78,10 +81,10 @@ DolphinStatusBar::DolphinStatusBar(QWidget *parent)
     m_stopButton->hide();
     connect(m_stopButton, &QToolButton::clicked, this, &DolphinStatusBar::stopPressed);
 
-    m_progressTextLabel = new QLabel(this);
+    m_progressTextLabel = new QLabel(contentsContainer);
     m_progressTextLabel->hide();
 
-    m_progressBar = new QProgressBar(this);
+    m_progressBar = new QProgressBar(contentsContainer);
     m_progressBar->hide();
 
     m_showProgressBarTimer = new QTimer(this);
@@ -115,18 +118,18 @@ DolphinStatusBar::DolphinStatusBar(QWidget *parent)
     m_progressBar->setFixedHeight(zoomSliderHeight);
     m_progressBar->setMaximumWidth(fontMetrics.averageCharWidth() * 20);
 
-    QHBoxLayout *topLayout = new QHBoxLayout(this);
+    m_topLayout = new QHBoxLayout(contentsContainer);
     updateContentsMargins();
-    topLayout->setSpacing(4);
-    topLayout->addWidget(m_label, 1);
-    topLayout->addWidget(m_zoomLabel);
-    topLayout->addWidget(m_zoomSlider, 1);
-    topLayout->addWidget(m_spaceInfo, 1);
-    topLayout->addWidget(m_stopButton);
-    topLayout->addWidget(m_progressTextLabel);
-    topLayout->addWidget(m_progressBar);
+    m_topLayout->setSpacing(4);
+    m_topLayout->addWidget(m_label, 1);
+    m_topLayout->addWidget(m_zoomLabel);
+    m_topLayout->addWidget(m_zoomSlider, 1);
+    m_topLayout->addWidget(m_spaceInfo, 1);
+    m_topLayout->addWidget(m_stopButton);
+    m_topLayout->addWidget(m_progressTextLabel);
+    m_topLayout->addWidget(m_progressBar);
 
-    setVisible(GeneralSettings::showStatusBar());
+    setVisible(GeneralSettings::showStatusBar(), WithoutAnimation);
     setExtensionsVisible(true);
     setWhatsThis(xi18nc("@info:whatsthis Statusbar",
                         "<para>This is "
@@ -249,7 +252,7 @@ int DolphinStatusBar::zoomLevel() const
 
 void DolphinStatusBar::readSettings()
 {
-    setVisible(GeneralSettings::showStatusBar());
+    setVisible(GeneralSettings::showStatusBar(), WithAnimation);
     setExtensionsVisible(true);
 }
 
@@ -345,9 +348,9 @@ void DolphinStatusBar::updateContentsMargins()
 {
     if (GeneralSettings::showSpaceInfo()) {
         // We reduce the outside margin for the flat button so it visually has the same margin as the status bar text label on the other end of the bar.
-        layout()->setContentsMargins(6, 0, 2, 0);
+        m_topLayout->setContentsMargins(6, 0, 2, 0);
     } else {
-        layout()->setContentsMargins(6, 0, 6, 0);
+        m_topLayout->setContentsMargins(6, 0, 6, 0);
     }
 }
 
@@ -360,4 +363,9 @@ void DolphinStatusBar::paintEvent(QPaintEvent *paintEvent)
     style()->drawPrimitive(QStyle::PE_PanelStatusBar, &opt, &p, this);
 }
 
+int DolphinStatusBar::preferredHeight() const
+{
+    return m_spaceInfo->height();
+}
+
 #include "moc_dolphinstatusbar.cpp"
diff --git a/src/statusbar/dolphinstatusbar.h b/src/statusbar/dolphinstatusbar.h
index 5cb1c4b60..75a2cdc6f 100644
--- a/src/statusbar/dolphinstatusbar.h
+++ b/src/statusbar/dolphinstatusbar.h
@@ -7,8 +7,9 @@
 #ifndef DOLPHINSTATUSBAR_H
 #define DOLPHINSTATUSBAR_H
 
+#include "animatedheightwidget.h"
+
 #include <QTime>
-#include <QWidget>
 
 class QUrl;
 class StatusBarSpaceInfo;
@@ -18,6 +19,7 @@ class QToolButton;
 class QSlider;
 class QTimer;
 class KSqueezedTextLabel;
+class QHBoxLayout;
 
 /**
  * @brief Represents the statusbar of a Dolphin view.
@@ -25,7 +27,7 @@ class KSqueezedTextLabel;
  * The statusbar allows to show messages, progress
  * information and space-information of a disk.
  */
-class DolphinStatusBar : public QWidget
+class DolphinStatusBar : public AnimatedHeightWidget
 {
     Q_OBJECT
 
@@ -123,6 +125,9 @@ private:
 
     void updateContentsMargins();
 
+    /** @see AnimatedHeightWidget::preferredHeight() */
+    int preferredHeight() const override;
+
 private:
     QString m_text;
     QString m_defaultText;
@@ -140,6 +145,8 @@ private:
 
     QTimer *m_delayUpdateTimer;
     QTime m_textTimestamp;
+
+    QHBoxLayout *m_topLayout;
 };
 
 #endif