Update: Possible solution at the bottom.
I am learning App development for Sailfish with very little prior experience in Qt/QML but some experience in other Toolkits (GTK, Tk, Motif, Xaw).
I am currently writing a dumb chat client (no protocoll, just send text over network.) I have the Talk/Chat page defined in QML as follows:
import QtQuick 2.0
import Sailfish.Silica 1.0
Page {
id: talkPage
PageHeader {
id: header
title: qsTr("Talk")
width: parent.width
anchors.top: parent.top
}
TextField {
id: message
placeholderText: qsTr("Type your Message...")
width: parent.width
anchors.bottom: parent.bottom
EnterKey.onClicked: {
log.text += "\n> " + text;
text = "";
}
}
TextArea {
id: log
readOnly: true
wrapMode: TextEdit.Wrap
width: parent.width
anchors.top: header.bottom
anchors.bottom: message.top
text: qsTr("Talk log")
}
}
You can now enter text in the message TextField and hit enter to add it to the log TextArea.
Question: How to I make the TextArea auto-scroll to the bottom each time a message is added to it.
Note that if I understand correctly, this is using Sailfish.Silica TextField, and this is different from standard (QtQuick.Components ?) So I cannot use log.append("\n> " + text); from QtQuick.Controls (which isn't available on Sailfish.)
A sollution in using C++ rather than Javascript/QML is fine to, since I'll need it to handle Networking anyway.
Thanks in advance for any suggestions!
Bonus Question: I tried arranging header, message and log in a Column previously, but didn't know how to make header and message keep their default height but make log expand to fill the screen. In GTK there is an expand property for this. Any hints?
Possible Solution: Put the TextArea inside a SilicaFlickable. For some reason TextArea is already scrollable without this extra step, but this way one can use scrollToBottom() and force the desired behavior. As a bonus, in this way we can add a nice scrollbar.
Related
I have a QML TextField that I am using with the Qt virtual keyboard to populate text. Occasionally when I am typing fast on the keyboard the cursor will jump unexpectedly to the end of the TextField. Has anyone seen any issues like this? I have ruled out unexpected focus changes as the cause by monitoring OnFocusedChanged while typing. Is there anything else that I might be able to monitor to determine why the cursor is moving to the end?
I am using QT version 5.15 and Virtual Keyboard Version 2.1.
EDIT: Adding code per request
TextField {
id: lotTextField
anchors.left: lotLine.left
anchors.top: lotImg.top
width: commonTextFieldWidth
height: lotImg.height
background: Item {}
text: startingLotCodeText
font.pixelSize: Style._SETTINGS_TEXT_SIZE_3_FONT_PIXEL_SIZE
onPressed: {
lotTextField.forceActiveFocus();
state_proxy.processEvent(EventsQML.EVENT_SHOW_KEYBOARD_REQUEST);
}
onTextEdited: {
state_proxy.checkLotCode(lotTextField.text, false);
}
onEditingFinished: {
state_proxy.checkLotCode(lotTextField.text, true);
scannerTextField.forceActiveFocus();
}
}
I am writing a small application that is working as follows:
1) I launch the application and I select a robot to which I will connect. See print screen below of the small app:
2) That will lead me to another page where I can actually choose the robot to connect to as shown in the print screen below:
3) Finally after selecting the robot the application brings me back to the initial screen that will show me an additional Button showing the chosen robot.
The problem: I have is that after I choose the robot and I am back to the initial screen and I push the button the color of the button should turn into a (for example) green color and changing the text into (for example) Connecting...
The code I am using is the following for which I am only putting the related part:
import QtQuick 2.12
import QtQuick.Controls 2.12
import QtQuick.Layouts 1.12
import QtQuick.Controls.Styles 1.4
Page {
property int dialogId: -1
signal selectDialog()
ColumnLayout {
anchors.fill: parent
spacing: 5
Button {
id: button1
text: "Select Robot"
onClicked: selectDialog()
Layout.fillWidth: true
font.pointSize: 20
}
Button {
id: dialogA
text: "FreddieMercury: Connect";
visible: dialogId === 1
Layout.fillWidth: true
font.pointSize: 20
function buttonClick()
{
console.log("Button "+ dialogA.text +" is clicked!")
}
Rectangle {
id: button
color: "red"
width: 96; height: 24; anchors.centerIn: parent
MouseArea {
id: region
anchors.fill: parent;
onClicked: console.log("clicked()")
onPressed: dialogA.color = "green"
onReleased: dialogA.color = "red"
}
Text {
id: st_text
anchors.centerIn: parent
text: "Connecting..."
font.bold: true
font.pointSize: 20
color: "green"
}
}
}
// Other Buttons
}
}
What I tried so far
I went through this source and also this post which I followed. As you can see from the point 3) I am close to the good functioning but there is clearly something I am not doing right.
Also this was useful and in fact I used the MouseArea option exactly from that post.
However I still don't see the whole color extended into the button.
Finally the text changed after the click event happened I included it in the Button as shown and thought that the property text: "Connecting..." was enough to overwrite the existing text but without success.
Please advise on what I am missing that is keeping me from a full working example.
I think the base issue is that you're trying to use examples for QtQuick Controls 1 with QtQuick Controls 2. They're completely different animals and you cannot style the v2 controls using QtQuick.Controls.Styles.
For customizing Controls 2 styles, like Button, see here. I also find it useful to look at the source code for the included controls (they're in your Qt library install folder inside /qml/QtQuick/Controls2/ directory). Though personally I find needing to re-create a whole new Button (or whatever) just to change a color or font is a bit much, especially if I want it to work across all the included QtQuick Controls2 Styles.
An alternative is to "hack" the properties of the built-in Control styles. This certainly has some drawbacks like if you want to be able to reset the control style back to default bindings, you'd have to save the original bindings and re-create them to reset the style. OTOH it beats creating customized controls for each style. YMMV.
Anyway here's an example of what i think you're looking for. This is based on our previous exercise with the buttons. :) Specifically, I just modified the Page1.qml code and the other 2 files are exactly the same as before. In this page I added buttonClick() handler and the Button::onClicked calls to trigger it from each button (and the button texts of course :).
Page1.qml
import QtQuick 2.12
import QtQuick.Controls 2.12
import QtQuick.Controls.impl 2.12 // for IconLabel
import QtQuick.Layouts 1.12
Page {
property int dialogId: -1;
signal selectDialog()
function buttonClick(button)
{
button.text = qsTr("Connecting to %1...").arg(button.text);
button.enabled = false; // prevent repeat clicks
// If Button has a background Rectangle object then we can set properties on it.
// note: `instanceof` was added in Qt 5.10
if (button.background && button.background instanceof Rectangle) {
button.background.color = "red"; // override style color
button.background.gradient = null; // some styles use a gradient
button.background.visible = true; // some styles may hide it in some situations
}
// Similar with the label element, IconLabel is used by all included QML styles.
if (button.contentItem && button.contentItem instanceof IconLabel) {
button.contentItem.color = "blue"; // override style color
button.contentItem.font.bold = true;
button.contentItem.font.pointSize = 20;
}
}
ColumnLayout {
anchors.fill: parent
spacing: 5
Button {
id: button1
text: "Select"
onClicked: selectDialog()
Layout.fillWidth: true
}
// These buttons should appear only after the user selects the choices on `Page2`
Button {
id: dialogA
text: "Freddie Mercury"
visible: dialogId === 1
Layout.fillWidth: true
onClicked: buttonClick(this)
}
Button {
id: dialogB
text: "David Gilmour"
visible: dialogId === 2
Layout.fillWidth: true
onClicked: buttonClick(this)
}
Button {
id: dialogC
text: "Mick Jagger"
visible: dialogId === 3
Layout.fillWidth: true
onClicked: buttonClick(this)
}
}
}
If you had a customized Button (like in the Qt docs example) then you could still do basically the same thing in buttonClick() but probably w/out worrying about the if (button.background ...) stuff (since you'd be sure your button has valid background/contentItem Items).
A better implementation of a "default" (Style-specific) Button but with custom colors/text properties would involve a subclass which uses Binding and/or Connections QML elements to control the properties and be able to reset them back to the current QtQuick Style defaults.
I want to have a widget in QML which has combination of the following behaviors:
1) Multi line edit
2) Auto scroll the content as and when I hit newline. (The content on top of the page keeps going up as and when I enter new content at the bottom)
3) Have a placeholder text functionality.
As far as I know, only Text and TextField are having placeholder text property and only TextArea is having a multi line edit plus auto scroll. But If there is any such widget with all the combinations then, my question “Dynamically swap the visibility/opacity between overlapping Text and TextArea “ would be invalid.
In case there is no such widget (I wonder why), I am thinking to have a rectangle which has both Text and TextArea overlapping and based on the below logic I want to have the visibility/opacity/focus on one of them:
If the Text Area is empty (0 characters), then have the Text in the foreground with focus and with the placeholder text “Enter some text”. But as soon as the user starts typing, the Text should lose the focus, opacity and go to background and the TextArea should gain the focus and come to the foreground and start accepting multi line input. Similarly, when TextArea is in the foreground and is empty (0 characters) and when the user click on any other widget outside my Rectangle, the Text should again gain the focus, come to the foreground and display the placeholder again.
I tried to get inspiration from this code, but failed miserably, it would be helpful if anyone can help me with a few lines of code or give me some pointers on how to solve this.
You can implement placeholderText for TextArea the same way Qt does in TextField. The source can be found here: TextField.qml
When you remove all the comments and properties, you basically have a background and on top of that a MouseArea, the placeholderText Text and a TextInput. Since you need to have the placeholder visually below the TextArea, you must have a transparent background:
PlaceholderTextArea.qml
import QtQuick 2.3
import QtQuick.Controls 1.2
Rectangle {
property alias placeholderText: placeholder.text
id: background
width: 640
height: 480
color: "#c0c0c0"
Text {
id: placeholder
anchors.fill: parent
renderType: Text.NativeRendering
opacity: !textArea.text.length && !textArea.activeFocus ? 1 : 0
}
TextArea {
id: textArea
anchors.fill: parent
backgroundVisible: false
}
}
and use your component:
PlaceholderTextArea {
placeholderText: qsTr("Hello World")
anchors.fill: parent
}
Here's an alternative implementation, that works a bit better for me:
import QtQuick 2.5
import QtQuick.Controls 1.4
import QtQuick.Controls.Styles 1.4
Item
{
property alias placeholderText: placeholder.text
property bool __shouldShowPlaceholderText:
!textArea.text.length && !textArea.activeFocus
// This only exists to get at the default TextFieldStyle.placeholderTextColor
// ...maybe there is a better way?
TextField
{
visible: false
style: TextFieldStyle
{
Component.onCompleted: placeholder.textColor = placeholderTextColor
}
}
TextArea
{
id: placeholder
anchors.fill: parent
visible: __shouldShowPlaceholderText
activeFocusOnTab: false
}
TextArea
{
id: textArea
anchors.fill: parent
backgroundVisible: !__shouldShowPlaceholderText
}
}
I'm going crazy. I have a ListView inside a ScrollView, hooked up to a model that inherits QAbstractListModel. When objects are added to the model, the ListView shows them using a delegate. So far, so good.
But I really want the view to stay scrolled to the bottom (like a chat window), and I'm having a very difficult time making that happen. Here is the relevant QML code:
Rectangle {
ScrollView {
[anchor stuff]
ListView {
id: messageList
model: textMessageFiltered
delegate: messageDelegate
}
}
TextField {
id: messageEditor
[anchor stuff]
onAccepted: {
controller.sendTextMessage(text)
text = ""
/* This works. */
//messageList.positionViewAtEnd();
}
}
Component {
id: messageDelegate
Rectangle {
anchors.left: parent.left
anchors.right: parent.right
color: "white"
height: nameText.height + 4
Text {
id: nameText
wrapMode: Text.Wrap
text: "<b>" + authorName + " (" + authorId + ")</b> " + message
[anchor stuff]
}
ListView.onAdd: {
console.log("This prints just fine!")
messageList.positionViewAtEnd()
}
}
}
}
The really strange thing, is that messageList.positionViewAtEnd() (at the end of the file) actually jumps it to the beginning. Without the call, the view stays where it is, even as new entries appear in the list. And indeed, if you look at the Qt documentation for the ListView.positionViewAtEnd(), it says:
Positions the view at the beginning or end, taking into account ...
Is that a silly error in the documentation, or what? I've tried everything I can think of to make this work, particularly the positionViewAtIndex() method and using highlighters to force the scroll to happen. But nothing works. Note the /* This works. */ comment in the source code above. When that is enabled, it works totally fine! (except of course, it jumps to the ListView.count()-2 index, instead of the end of the list)
Does anyone have any idea what might be wrong here? Any examples I could try to prove that there's a terrible, terrible bug in QML?
I'm using Qt 5.3.1 with QtQuick 2.0 (or 2.1 or 2.2 fail too). I've tried many, many other configurations and code as well, so please ask if you need more info. I've completely exhausted my google-fu.
Thanks!
Edit 1
While the accepted answer does solve the above problem, it involves adding the Component.onCompleted to the delegate. This seems to cause problems when you scroll the list, because (I believe) the delegates are added to the view when you scroll up, causing the onCompleted trigger to be called even if the model item isn't new. This is highly undesirable. In fact, the application is freezing when I try to scroll up and then add new elements to the list.
It seems like I need a model.onAdd() signal instead of using the existence of a delegate instance to trigger the scroll. Any ideas?
Edit 2
And how does this NOT work?
ListView {
id: messageList
model: textMessageFiltered
delegate: messageDelegate
onCountChanged: {
console.log("This prints properly.")
messageList.positionViewAtEnd()
}
}
The text "This prints properly" prints, so why doesn't it position? In fact, it appears to reset the position to the top. So I tried positionViewAtBeginning(), but that did the same thing.
I'm totally stumped. It feels like a bug.
You need to set the currentIndex as well.
testme.qml
import QtQuick 2.2
import QtQuick.Controls 1.1
import QtQuick.Window 2.0
ApplicationWindow {
title: qsTr("Hello World")
width: 300
height: 240
ScrollView {
anchors.fill: parent
ListView {
anchors.fill: parent
id: messageList
model: messageModel
delegate: Text { text: mytextrole }
highlight: Rectangle { color: "red" }
highlightMoveDuration: 0
onCountChanged: {
var newIndex = count - 1 // last index
positionViewAtEnd()
currentIndex = newIndex
}
}
}
ListModel {
id: messageModel
ListElement { mytextrole: "Dog"; }
ListElement { mytextrole: "Cat"; }
}
Timer {
property int counter: 0
running: true
interval: 500
repeat: true
onTriggered: {
messageModel.append({"mytextrole": "Line" + (counter++)})
}
}
}
There is still some jumping to the first element and jumping back down for a fraction of a second.
There is a note in documentation:
Note: methods should only be called after the Component has completed. To position the view at startup, this method should be called by Component.onCompleted.
Change your ListView.onAdd: to
Component.onCompleted: {
console.log("This prints just fine!")
messageList.positionViewAtEnd()
}
And it works well.
In your case, the ListView emits add signal before the new delegate is created and completed. The ListView is still working on something behind the scene, so positionViewAtEnd cannot work as expected. And /* This works. */ because it is called after the new delegate is completed. However, don't assume this always works. Simply follow the note, call positionViewAtEnd in Component.onCompleted, in documentation.
SDK: Qt Creator 2.4.1
Target: Nokia N9 and Windows 7
If I do the following in a qml file
import QtQuick 1.1
import com.nokia.meego 1.0
Page {
id: myShowChangeLogPage
TextEdit {
id: changeLogArea
anchors.top: titleBackground.bottom
width: parent.width
height: 300
text: "1\n1\n1\n1\n2\n1\n1\n1\n1\n1\n3\n1\n1\n1\n4\n1\n1\n1\n1\n5\n1\n1\n1\n6\n1\n1\n1\n7\n1\n1\n1\n8\n\n\n\n\n9"
font.pixelSize: 20
textFormat: TextEdit.AutoText
readOnly: true
wrapMode: TextEdit.WordWrap
}
}
The TextEdit area do not behave as I expected.
The String will be printed outside the size of the TextEdit area, that is,
it continues beneath the bottom screen edge.
There is no scrollbar/slider to the right
I was expecting that the the TextEdit element should automatically create a
scrollbar/slider if the string is to large to fit within the boundaries.
I have been told that TextEdit should do this and there is no need for a Flicker
or ScrollArea.
I have tried other type of components such as Text and TextEdit and also encapsulate
the TextEdit in a rectangle without any luck.
Regards
I read this right at the beginning of the documentation regarding the TextEdit element:
Note that the TextEdit does not implement scrolling, following the
cursor, or other behaviors specific to a look-and-feel.
There is also a complete example of how to implement scrolling for following the cursor.
TextEdit in qml doesn't implement scrolling. You must to use another one, such as TextArea (https://doc.qt.io/qt-5/qml-qtquick-controls2-textarea.html), then place it inside a ScrollView. Here's an example:
// Creating a scrollable TextEdit
ScrollView {
id: view
anchors.fill: parent
TextArea {
text: "TextArea\n...\n...\n...\n...\n...\n...\n"
}
}