widget

问题 I have created a widget using Qt Creator such a way that it has two sub windows inside a main window and some push buttons to load, save images, set pen width and color to paint on the window. But when i start to paint it gives me error saying QWidget::paintEngine: Should no longer be called QPainter::begin: Paint device returned engine == 0, type: 1 QPainter::setPen: Painter not active QPainter::drawPoints: Painter not active Does anyone know what mistake i am doing, i checked threads

问题 I have created a widget using Qt Creator such a way that it has two sub windows inside a main window and some push buttons to load, save images, set pen width and color to paint on the window. But when i start to paint it gives me error saying QWidget::paintEngine: Should no longer be called QPainter::begin: Paint device returned engine == 0, type: 1 QPainter::setPen: Painter not active QPainter::drawPoints: Painter not active Does anyone know what mistake i am doing, i checked threads

问题 I've been trying to configure the border colour of a widget in Tkinter, and I was wondering how to do that.... I've checked on StackOverflow, and it says that I should use the configure option and then set highlightbackgroundcolor = {insert color here} . I've tried that and nothing has worked. Can someone please show me a working sample of code so I can figure it out? 回答1: There is no way to change the border color of a widget, the border color is tied to the background color of the widget.

问题 I've been trying to configure the border colour of a widget in Tkinter, and I was wondering how to do that.... I've checked on StackOverflow, and it says that I should use the configure option and then set highlightbackgroundcolor = {insert color here} . I've tried that and nothing has worked. Can someone please show me a working sample of code so I can figure it out? 回答1: There is no way to change the border color of a widget, the border color is tied to the background color of the widget.

问题 I've been trying to configure the border colour of a widget in Tkinter, and I was wondering how to do that.... I've checked on StackOverflow, and it says that I should use the configure option and then set highlightbackgroundcolor = {insert color here} . I've tried that and nothing has worked. Can someone please show me a working sample of code so I can figure it out? 回答1: There is no way to change the border color of a widget, the border color is tied to the background color of the widget.

问题 I was able to get my layout working with static kivy language but I need to be able to add items to my list via python. I've tried several things but can't seem to get anything working correctly. Here's what I have working statically. main.py #!/usr/bin/python import os import kivy kivy.require('1.8.0') from kivy.app import App from kivy.core.window import Window from kivy.logger import Logger from kivy.uix.boxlayout import BoxLayout from kivy.uix.button import Button class CustomButton

问题 I'd like to know how to center the contents a Text widget vertically and horizontally in Flutter. I only know how to center the widget itself using Center(child: Text("test")) but not the content itself, it's by default left aligned. In Android, I believe the property of a TextView that achieves this is called gravity . Example of what I want: 回答1: Text alignment center property setting only horizontal alignment. I used below code to set text vertically and horizontally center. Code: child:

问题 I'd like to know how to center the contents a Text widget vertically and horizontally in Flutter. I only know how to center the widget itself using Center(child: Text("test")) but not the content itself, it's by default left aligned. In Android, I believe the property of a TextView that achieves this is called gravity . Example of what I want: 回答1: Text alignment center property setting only horizontal alignment. I used below code to set text vertically and horizontally center. Code: child:

问题 I took the red screen '_Type' is not a subtype of type 'Widget' exception in NoContentPage I wrote down the full component code and called place into StatefulWidget. What is wrong in this code. I think it is a very common exception in the flutter. class NoContentPage extends StatelessWidget { @override Widget build(BuildContext context) { return (new Container( width: 320.0, child: new Column( children: <Widget>[ Center( child: Text(AppLocalizations.of(context).messageNoContent, style:

问题 I took the red screen '_Type' is not a subtype of type 'Widget' exception in NoContentPage I wrote down the full component code and called place into StatefulWidget. What is wrong in this code. I think it is a very common exception in the flutter. class NoContentPage extends StatelessWidget { @override Widget build(BuildContext context) { return (new Container( width: 320.0, child: new Column( children: <Widget>[ Center( child: Text(AppLocalizations.of(context).messageNoContent, style: