Mobile: ensure input fields stay visible after keyboard opens

When the user taps on a TextField to enter text, usually the virtual
keyboard will pop up. This code tries to ensure that the keyboard
doesn't cover the entry field that the user was trying to work on.

In order to centralize these changes, this introduces a new
SsrfTextField type which we use to also remove a few redundant default
settings that we previously had for every field. The one TextArea for
the Notes field didn't seem worth creating yet another type for, so
there the changes are done directly in DiveDetailsEdit.

The awkward timer mechanism is necessary as the keyboard pops up
asynchronously and then triggers a change of height for the app, so we
need to wait a little bit before doing the adjustment.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

3 files changed, 127 insertions, 111 deletions

diff --git a/mobile-widgets/qml/DiveDetailsEdit.qml b/mobile-widgets/qml/DiveDetailsEdit.qml
index 18df5ab46..266f275a4 100644
--- a/mobile-widgets/qml/DiveDetailsEdit.qml
+++ b/mobile-widgets/qml/DiveDetailsEdit.qml
@@ -163,13 +163,10 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtDate;
 				Layout.fillWidth: true
-				onEditingFinished: {
-					focus = false
-				}
-				color: subsurfaceTheme.textColor
+				flickable: detailsEditFlickable
 			}
 			Controls.Label {
 				Layout.alignment: Qt.AlignRight
@@ -201,13 +198,10 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtGps
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -238,14 +232,11 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtDepth
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
 				validator: RegExpValidator { regExp: /[^-]*/ }
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 			Controls.Label {
 				Layout.alignment: Qt.AlignRight
@@ -253,14 +244,11 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtDuration
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
 				validator: RegExpValidator { regExp: /[^-]*/ }
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -269,13 +257,10 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtAirTemp
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -284,13 +269,10 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtWaterTemp
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -363,14 +345,11 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtWeight
 				readOnly: text === "cannot edit multiple weight systems"
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 // all cylinder info should be able to become dynamic instead of this blob of code.
 // first cylinder
@@ -395,15 +374,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtGasMix0
 				text: usedGas[0] != null ? usedGas[0] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
 				validator: RegExpValidator { regExp: /(EAN100|EAN\d\d|AIR|100|\d{1,2}|\d{1,2}\/\d{1,2})/i }
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -412,14 +388,11 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtStartPressure0
 				text: startpressure[0] != null ? startpressure[0] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -428,14 +401,11 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				id: txtEndPressure0
 				text: endpressure[0] != null ? endpressure[0] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 //second cylinder
 			Controls.Label {
@@ -462,16 +432,13 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[1] != null ? true : false
 				id: txtGasMix1
 				text: usedGas[1] != null ? usedGas[1] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
 				validator: RegExpValidator { regExp: /(EAN100|EAN\d\d|AIR|100|\d{1,2}|\d{1,2}\/\d{1,2})/i }
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -481,15 +448,12 @@ Item {
 				color: subsurfaceTheme.textColor
 				font.pointSize: subsurfaceTheme.smallPointSize
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[1] != null ? true : false
 				id: txtStartPressure1
 				text: startpressure[1] != null ? startpressure[1] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -499,15 +463,12 @@ Item {
 				color: subsurfaceTheme.textColor
 				font.pointSize: subsurfaceTheme.smallPointSize
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[1] != null ? true : false
 				id: txtEndPressure1
-				text: endpressure[1] != null ? endpressure[1] : null 
+				text: endpressure[1] != null ? endpressure[1] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 // third cylinder
 			Controls.Label {
@@ -535,16 +496,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[2] != null ? true : false
 				id: txtGasMix2
 				text: usedGas[2] != null ? usedGas[2] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
 				validator: RegExpValidator { regExp: /(EAN100|EAN\d\d|AIR|100|\d{1,2}|\d{1,2}\/\d{1,2})/i }
-				onEditingFinished: {
-					focus = false
-				}
 			}
 
 			Controls.Label {
@@ -554,15 +511,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[2] != null ? true : false
 				id: txtStartPressure2
 				text: startpressure[2] != null ? startpressure[2] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -572,15 +526,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[2] != null ? true : false
 				id: txtEndPressure2
 				text: endpressure[2] != null ? endpressure[2] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 // fourth cylinder
 			Controls.Label {
@@ -608,16 +559,13 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[3] != null ? true : false
 				id: txtGasMix3
 				text: usedGas[3] != null ? usedGas[3] : null
 				Layout.fillWidth: true
 				validator: RegExpValidator { regExp: /(EAN100|EAN\d\d|AIR|100|\d{1,2}|\d{1,2}\/\d{1,2})/i }
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -627,15 +575,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[3] != null ? true : false
 				id: txtStartPressure3
 				text: startpressure[3] != null ? startpressure[3] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -645,15 +590,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[3] != null ? true : false
 				id: txtEndPressure3
 				text: endpressure[3] != null ? endpressure[3] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 // fifth cylinder
 			Controls.Label {
@@ -681,16 +623,13 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[4] != null ? true : false
 				id: txtGasMix4
 				text: usedGas[4] != null ? usedGas[4] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
 				validator: RegExpValidator { regExp: /(EAN100|EAN\d\d|AIR|100|\d{1,2}|\d{1,2}\/\d{1,2})/i }
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -700,15 +639,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[4] != null ? true : false
 				id: txtStartPressure4
 				text: startpressure[4] != null ? startpressure[4] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -718,15 +654,12 @@ Item {
 				font.pointSize: subsurfaceTheme.smallPointSize
 				color: subsurfaceTheme.textColor
 			}
-			Controls.TextField {
+			SsrfTextField {
 				visible: usedCyl[4] != null ? true : false
 				id: txtEndPressure4
 				text: endpressure[4] != null ? endpressure[4] : null
 				Layout.fillWidth: true
-				color: subsurfaceTheme.textColor
-				onEditingFinished: {
-					focus = false
-				}
+				flickable: detailsEditFlickable
 			}
 
 			Controls.Label {
@@ -775,6 +708,31 @@ Item {
 				Layout.minimumHeight: Kirigami.Units.gridUnit * 6
 				selectByMouse: true
 				wrapMode: TextEdit.WrapAtWordBoundaryOrAnywhere
+				property bool firstTime: true
+				onPressed: waitForKeyboard.start()
+
+				// we repeat the Timer / Function from the SsrfTextField here (no point really in creating a matching customized TextArea)
+				function ensureVisible(yDest) {
+					detailsEditFlickable.contentY = yDest
+				}
+
+				// give the OS enough time to actually resize the flickable
+				Timer {
+					id: waitForKeyboard
+					interval: 300 // 300ms seems like FOREVER
+					onTriggered: {
+						if (!Qt.inputMethod.visible) {
+							if (firstTime) {
+								firstTime = false
+								restart()
+							}
+							return
+						}
+						// make sure at least half the Notes field is visible
+						if (txtNotes.y + txtNotes.height / 2 > detailsEditFlickable.contentY + detailsEditFlickable.height - 3 * Kirigami.Units.gridUnit || txtNotes.y < detailsEditFlickable.contentY)
+							txtNotes.ensureVisible(Math.max(0, 3 * Kirigami.Units.gridUnit + txtNotes.y + txtNotes.height / 2 - detailsEditFlickable.height))
+					}
+				}
 			}
 		}
 		Item {
diff --git a/mobile-widgets/qml/SsrfTextField.qml b/mobile-widgets/qml/SsrfTextField.qml
new file mode 100644
index 000000000..d4ec5098a
--- /dev/null
+++ b/mobile-widgets/qml/SsrfTextField.qml
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+import QtQuick 2.2
+import QtQuick.Controls 2.2 as Controls
+import org.kde.kirigami 2.4 as Kirigami
+
+Controls.TextField {
+	/**
+	 * set the flickable property to the Flickable this TextField is part of and
+	 * when the user starts editing the text this should stay visible
+	 */
+	property var flickable
+	property bool firstTime: true
+
+	id: stf
+
+	// while we are at it, let's put some common settings here into the shared element
+	color: subsurfaceTheme.textColor
+	onEditingFinished: {
+		focus = false
+		firstTime = true
+	}
+
+	// that's when a user taps on the field to start entering text
+	onPressed: {
+		if (flickable !== undefined) {
+			waitForKeyboard.start()
+		} else {
+			console.log("flickable is undefined")
+		}
+	}
+
+	// give the OS enough time to actually resize the flickable
+	Timer {
+		id: waitForKeyboard
+		interval: 300 // 300ms seems like FOREVER, but even that sometimes isn't long enough on Android
+
+		onTriggered: {
+			if (!Qt.inputMethod.visible) {
+				if (firstTime) {
+					firstTime = false
+					restart()
+				}
+				return
+			}
+			// make sure there's enough space for the input field above the keyboard and action button (and that it's not too far up, either)
+			if (stf.y + stf.height > flickable.contentY + flickable.height - 3 * Kirigami.Units.gridUnit || y < flickable.contentY)
+				ensureVisible(Math.max(0, 3 * Kirigami.Units.gridUnit + stf.y + stf.height - flickable.height))
+		}
+	}
+
+	// scroll the flickable to the desired position if the keyboard has shown up
+	// this didn't work when setting it from within the Timer, but calling this function works.
+	// go figure.
+	function ensureVisible(yDest) {
+		flickable.contentY = yDest
+	}
+}
diff --git a/mobile-widgets/qml/mobile-resources.qrc b/mobile-widgets/qml/mobile-resources.qrc
index 3cf536d6d..9cab0f502 100644
--- a/mobile-widgets/qml/mobile-resources.qrc
+++ b/mobile-widgets/qml/mobile-resources.qrc
@@ -21,6 +21,7 @@
 		<file>SsrfButton.qml</file>
 		<file>SsrfCheckBox.qml</file>
 		<file>SsrfSwitch.qml</file>
+		<file>SsrfTextField.qml</file>
 
 		<!-- ********** pictures ********** -->
 		<file>icons/dive.jpg</file>