How to make a progressbar with a icon? - xamarin.forms

I know how to set the width of the progressBar by renderer it in ios/android.But is there anyway to add a image in the progressbar?
I have set its height.
protected override void OnElementChanged(ElementChangedEventArgs<ProgressBar> e)
{
base.OnElementChanged(e);
Control.ScaleY = 20;
}
and in ios:
public override void LayoutSubviews()
{
base.LayoutSubviews();
var x = 1.0f;
var y = 20.0f;
CGAffineTransform transform = CGAffineTransform.MakeScale(x, y);
Control.Transform = transform;
}
but I wonder if there is anyway to add an icon?
this is my goal to achive:
progressBar
it is a 98 percent progressBar with a star in the end of the progress value.I've no idea to achive it

Maybe it's too late to reply now
Have you try to use Slider and use CustomRender to custom the style of SeekBar,it has the
android:thumb="#drawable/seekbarthumb" attribute,set your star icon to the thumb more easily

at last I use relativelayout to fix the postion of the image. as #Skin says.

Related

Xamarin Forms UWP specifying button width request with an effect

I would like to specify the width of a Xamarin.Forms.Button with an effect in UWP, something like:
protected override void OnAttached()
{
if (VisualElement is Xamarin.Forms.Button buttonControl)
{
buttonControl.WidthRequest = 40;
buttonControl.BorderWidth = 1;
}
}
VisualElement is an invalid type. What goes in its place? Thank you!
Xamarin Forms UWP specifying button width request with an effect
In Xamarin effect class, the attached control is referenced with Element property but not VisualElement, please edit your code like the following and you will get forms button on OnAttached method.
protected override void OnAttached()
{
if (Element is Xamarin.Forms.Button buttonControl)
{
buttonControl.WidthRequest = 40;
buttonControl.BorderWidth = 1;
}
}

HOWTO: Manipulate Back Arrow Icon and Button on Navigation Bar (Xamarin Forms / Android)

I am attempting to change the size of the back arrow in the navigation bar.
Using information from this article, I have added the following code:
protected override Task<bool> OnPushAsync(Page view, bool animated)
{
var result = base.OnPushAsync(view, animated);
var activity = (Activity) Context;
var toolbar = activity.FindViewById<Toolbar>(Resource.Id.toolbar);
if (toolbar != null)
{
if (toolbar.NavigationIcon != null)
{
if (toolbar.NavigationIcon is DrawerArrowDrawable navigationIcon)
{
// Code goes here?
}
}
}
return result;
}
If this is indeed the correct path, what code goes in the area marked by the comment "Code goes here?"?
* UPDATE *
I realized that what I am trying to figure out was not exactly described in my original question.
More specifically, when I mentioned that I am trying to resize the navigation bar back arrow, what I am really trying to do is to resize the button that the icon appears on.
For example, if I shrink the height of the navigation bar using code like the following:
On<Android>().SetBarHeight(100);
The button that the icon appears on will be clipped.
Ultimately, what I am trying to accomplish is resizing the icon AND the button that the icon appears on. I have already figured out how to do the former.
I am attempting to change the size of the back arrow in the navigation bar.
If you want to change size of the back button in the navigation bar, you can get new icon from Drawable in resource for toolbar.NavigationIcon.
public class NavigationPageRenderer : Xamarin.Forms.Platform.Android.AppCompat.NavigationPageRenderer
{
public AppCompToolbar toolbar;
public Activity context;
protected override Task<bool> OnPushAsync(Page view, bool animated)
{
var retVal = base.OnPushAsync(view, animated);
context = (Activity)Forms.Context;
toolbar = context.FindViewById<AppCompToolbar>(Droid.Resource.Id.toolbar);
if (toolbar != null)
{
if (toolbar.NavigationIcon != null)
{
if (toolbar.NavigationIcon is DrawerArrowDrawable navigationIcon)
{
// Code goes here?
toolbar.NavigationIcon = Android.Support.V7.Content.Res.AppCompatResources.GetDrawable(context, Resource.Drawable.back);
toolbar.Title = "Back";
}
}
}
return retVal;
}
}
Here is the sample you can take a look:
https://github.com/hachi1030-Allen/XamarinCustomNavBar
<NavigationPage.TitleView> will help you out there. This is a XAML approach.
Example:
<NavigationPage.TitleView>
<StackLayout>
....
</StackLayout>
</NavigationPage.TitleView>
Using this approach you will be able to set HeightRequest and WidthRequest of whatever element you place inside the StackLayout and whatever else you want to amend.
Also, note that if you are having icon size problems it may be worth looking into whether or not your drawable/ icons are the right size for the right resolution.

Gradient as background on a grid in Xamarin.Forms

I'm trying to use a gradient brush for a background on a Grid. So far I've created a custom renderer for the UWP only but I can't get that to work.
The e.NewElement.BackgroundColor expects a Color, but I have a LinearGradientBrush. So is it even possible to set the grid background as a gradient color?
Thanks
My renderer code is below:
public class MyGridRenderer:ViewRenderer<MyGrid, Grid>
{
protected override void OnElementChanged(ElementChangedEventArgs<MyGrid> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
LinearGradientBrush brush = new LinearGradientBrush();
GradientStop start = new GradientStop();
start.Offset = 0;
start.Color = Colors.Yellow;
brush.GradientStops.Add(start);
GradientStop stop = new GradientStop();
stop.Offset = 1;
stop.Color = Colors.Black;
brush.GradientStops.Add(stop);
e.NewElement.BackgroundColor = brush; //What goes here
//Control.Background = brush;
}
}
}
I have the answer.
There is a background property.
so:
Background=brush

Qt painted content goes lost

I am writing an info-screen program. I created a full-screen widget and draw contents onto it.
In order to extend the life cycle of the TFT-display device, I want to implement a pixel-shifting feature. With other words, in every X minutes, I shift the screen to left/right/top/down for Y pixels.
My approach is as follows:
I use two layers (two QWidget).
I paint contents on the top layer.
When a pixel-shifting is performed, I just move the top layer for specified offset.
And then fill a background color to the bottom layer.
However, I found a problem:
If I move up the top layer for 10 pixels, the 10-pixel-content goes out of the screen. But when I move this layer down for 10 pixels. The 10-pixel-content will not be updated, it is gone.
How can I keep these 10-pixel-content? Is there any magic widget flag to solve this problem?
UPDATE 1:
The code is written in language D, but it is easy to understand:
class Canvas: QWidget
{
private QPixmap content;
this(QWidget parent)
{
super(parent);
setAttribute(Qt.WA_OpaquePaintEvent, true);
}
public void requestForPaint(QPixmap content, QRegion region)
{
this.content = content;
update(region);
}
protected override void paintEvent(QPaintEvent event)
{
if (this.content !is null)
{
QPainter painter = new QPainter(this);
painter.setClipping(event.region);
painter.fillRect(event.region.boundingRect, new QColor(0, 0, 0));
painter.drawPixmap(event.region.rect, this.content);
this.content = null;
painter.setClipping(false);
}
}
}
class Screen: QWidget
{
private Canvas canvas;
this()
{
super(); // Top-Level widget
setAutoFillBackground(True);
this.canvas = new Canvas(this);
showFullScreen();
}
public void requestForPaint(QPixmap content, QRegion region)
{
this.canvas.requestForPaint(content, region);
}
private updateBackgroundColor(QColor backgroundColor)
{
QPalette newPalette = palette();
newPalette.setColor(backgroundRole(), backgroundColor);
setPalette(newPalette);
}
public shiftPixels(int dx, int dy)
{
this.canvas.move(dx, dy);
updateBackgroundColor(new QColor(0, 0, 0)); // Just a demo background color
}
}
Screen screen = new Screen;
screen.requestForPaint(some_content, some_region);
screen.shiftPixels(0, -10);
screen.shiftPixels(0, 10);
Looking at the code, my first guess is that your region might be wrong. Try repainting the whole widget each time, and see if that solves the missing 10 pixel problem. If it does, then try working out why your region isn't covering the newly exposed portion.
One possibility along those lines: I notice in your Screen::requestForPaint method that you directly call the Canvas::requestForPaint without doing anything with the region. In Qt, the coordinates for anything like that are often assumed to be local, so if you don't account for the current position of the canvas widget, you might get an incorrect region.
Why not setting the position of the widget directly...? Another options might be using QPainter::translate(-1,-1) or something similar.

How to manage Mouse clicks on Irregular Button shapes in Flex

In Flex, I am trying to design 3 buttons similar to the image uploaded at
http://www.freeimagehosting.net/uploads/f14d58b49e.jpg
The mouse over/click on image should work only on red colored area of the button.
How can I manage the Mouse clicks or Irregular Button shapes in Flex?
Thnx ... Atul
Check this out: flexlib > ImageMap.
Taken from stackOverflow
Use button skins based on a vector graphic (e.g., one made in Illustrator), save each state as a named symbol in the document, then export as SWF. Reference the skins as follows:
.stepButton {
upSkin: Embed(source="myfile.swf", symbol="StepButton");
downSkin: Embed(source="myfile.swf", symbol="StepButtonDown");
overSkin: Embed(source="myfile.swf", symbol="StepButtonOver");
disabledSkin: Embed(source="myfile.swf", symbol="StepButtonDisabled");
}
Flash will automatically determine the hit area from the visible portion. This example (not called "myfile.swf") is working for us right now in an application.
Create ArrowButtonsHolder class by inheriting from Canvas
Create 3 children classes also inherited from Canvas. For example LeftArrowButton, MiddleArrowButton, RightArrowButton
public class LeftArrowButton:Canvas {
protected override function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
{
super.updateDisplayList(unscaledWidth, unscaledHeight);
// draw your arrow here
// use graphics to do it
graphics.beginFill(0xFF0000);
graphics.lineStyle(1, 0x000000);
graphics.moveTo(0, 0);
graphics.lineTo(30, 0);
graphics.lineTo(50, 25);
graphics.lineTo(30, 50);
graphics.lineTo(0, 50);
graphics.lineTo(0, 0);
graphics.endFill();
}
}
You also can create general class ArrowButton and inherit another 3 from that class and override drawing function
Add this 3 child button object to ArrowButtonsHolder by overriding createChildren():void method
public class ArrowButtonsHolder:Canvas {
// ...
private var leftArrowButton:LeftArrowButton;
private var middleArrowButton:MiddleArrowButton;
private var rightArrowButton:RightArrowButton;
// ...
protected override function createChildren():void {
super();
// create buttons
leftArrowButton = new LeftArrowButton();
middleArrowButton = new LeftArrowButton();
rightArrowButton = new LeftArrowButton();
// add them to canvas
addChild(leftArrowButton);
addChild(middleArrowButton);
addChild(rightArrowButton);
// position these button by adjusting x, y
leftArrowButton.x = 0;
middleArrowButton.x = 50;
rightArrowButton.x = 100;
// assign event listeners
leftArrowButton.addEventListener(MouseEvent.CLICK, onLeftArrowButtonClick);
middleArrowButton.addEventListener(MouseEvent.CLICK, onMiddleArrowButtonClick);
rightArrowButton.addEventListener(MouseEvent.CLICK, onRightArrowButtonClick);
}
private onLeftArrowButtonClick(event:MouseEvent):void
{
trace("Left button clicked");
}
// .. etc for another 2 methods implemented here
}
PS: There might be tons of syntax mistakes in my code but you should get general idea how to do it

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