I want to display multiple QML Files on a QWidget. Because every Display should be an unique Object/Widget, I plan to use for every display an own QGraphicsView with an unique QGraphicsScene. These views can be added to a layout witch will be placed on a widget.
So I will have about 50-100 QGraphicsScenes and GraphicsViews.
I want to set a background for the Displays which will not be updated when you repaint the object. That is why I want to use an own scene for each display.
Is this recommended or should I use only one GraphicsScene in a project?
It's not good idea, 50-100 scenes is not optimal. Why not drawing all QML files in same QML View ? Using Loader foreach file.
Related
I have a UWP app that I am working on, and using absolute position creates problems when using the app on screen sizes different than the one it was designed for.
I'm not sure how exactly i should place elements at distances from each other without using margin and absolute position. How should I be doing this?
Edit: I am using XAML to design the UI.
Well, it depends on what UI you want to build up.
There are various panels and, usually, there is NO need to use absolute position in most cases.
Usually, the Grid panel is used to create flexible layouts, by adding rows and columns: for example, if you want to create a page with some content and a bottom app bar with buttons on it, you usually create a Grid with as many rows as you need for your content controls, plus one for the bottom appbar itself.
Years ago, I also started building UIs by using absolute position for every element, but then times passes and you start having a flexible mind in order to build flexible layouts.
Sorry to not answer any further, but your question is just TOO broad to give any precise answer.
Best regards
How do you properly position elements in XAML without using absolute position?
You should use an appropriate layout panel:
Layout panels are containers that allow you to arrange and group UI elements in your app. The built-in XAML layout panels include RelativePanel, StackPanel, Grid, VariableSizedWrapGrid, and Canvas.
We have been working in a Tree Editor. We are displaying icons below the file names. Now, we have a need to display another icons below this already displayed icon. This icon will be displayed based on some parameters. Hence, it is not necessary that always multiple icons will be displayed.
We have our own LabelProvider which correctly returns a single image.
Please, let me know how can I customise my LabelProvider to return multiple images ?
The normal LabelProvider only supports returning a single image per row.
There are some classes available which let you make a composite image from several separate images. The abstract base class for these is CompositeImageDescriptor. The DecorationOverlayIcon class is a concrete class based in this which supports a main image with up to four overlay images (this is what views like Package Explorer use).
If those classes are not enough you can use a label provider based on OwnerDrawLabelProvider - which allows you to draw what you like in the row.
Note: All rows in a tree (or table) are always the same height. A deep image in one row will force all the other rows to be the same depth.
I have a label which displays dynamic text. For example, However, I want to add a slide in/slide out feature to the text that appears on the label. How can I do that ?
I have a made an helper library for Titanium animations that you can find here https://github.com/raulriera/Animator
However, if you want to do this yourself "by hand", uou can achieve this using the 2DMatrix API http://docs.appcelerator.com/titanium/latest/#!/api/Titanium.UI.2DMatrix you want to take a look at the translate method (which is the one responsible for moving views)
Application requires more than one window (Lets call A,B,C). Each window has more than one view (table views, image views as well as web view). Lets say window A has three views (x, y,z) and window B has three views (d,e,f). Application needs to display images of different size on orientation change.
I have achieved the same using gesture event listener and looping through windows for views and replacing the view with new images. The problem I have is when we navigate from one window to other and the orientation changes, the loading of view after looping goes for a toss. Is there a better way to achieve the same ?
Is there a method in titanium like following code to replace a view ?
var self=Ti.UI.currentWindow
var newView=Ti.UI.createImageView({image:'abc.png'})
self.replace(self.children[1],newView )
Unfortunately there is now replace method.
You need to remove the whole view and add it again but this can cause a wrong layout if you have more than one view on a same level. The implementation then depends on the layout which was set (vertical, horizontal, composite etc).
For example in vertical layout removing an item and simply add a new one would remove your specified item but appends the new one at the end since you can't specify in which order it should be added.
If you have a composite layout you can specify absolute positions but adding a new view causes a higher zIndex for this view so that it will hide views that were previously added at the same/similar position.
Why not simply change the image link ?
var self = Ti.UI.currentWindow;
self.children[1].image = 'bcd.png';
Well you could always lock the orientation of your window. But this isnt exactly good practice (especially for iOS).
Generally orientation changes are handled pretty well if you define the width and height of your views to be percentages or Ti.UI.FILL, if you have a composite layout. Check that you are not giving the views absolute coordinates as this could cause layout problems. If you have a vertical or horizontal layout you usually don't have to worry about orientation change, unless you did not nest your views in a main container correctly.
Prasad,
If this is about just ensuring that the images look good on different orientations,you can make use of the different folders provided by Titanium in the android/images folder.You can just make different images for each of the orientations and device sizes.For IOS you can change just the images on orientation change as you are already doing.
https://wiki.appcelerator.org/display/guides/Using+density-specific+resources+on+Android
If you are concernced about the layout there are couple of things you can do:
1.Give all the height or width values in percentages.This way all elements will be re sized once the orientation changes automatically.
2.On each window open check if the orientation is vertical or horizontal by default and accordingly set the image attribute of the imageView.
Ti.UI.orientation
This property will give you the orientation of the window by default.Values of this property could be this
Ti.UI.PORTRAIT
Ti.UI.UPSIDE_PORTRAIT
Ti.UI.LANDSCAPE_LEFT
Ti.UI.LANDSCAPE_RIGHT
Use "if else" and accordingly set the images.
I have seen that in Cocoa I can create a custom view using drawing primitives which allows me to draw what I like but at a very low level.
Instead I'd like to create custom widgets using a combination of existing controls. For example:
I'd like to create a table with images and combobox in cells
I'd like to create a custom widget wich is a combination of several (for example a list, a button and combobox)
How can I approach this problem ?
Secondly a typical cocoa developer uses external controls? Is there a repository or a list of interesting external custom controls (commercial or free) ?
I'd like to create a table with images and combobox in cells
There already exists NSImageCell and NSComboBoxCell. Are you sure you need to do anything different?
If the problem is that you want an image and a combo box in the same cell, you will have to subclass NSCell. Currently table views can only contain cells, not views, which makes your life harder (as understanding how cell drawing works is more difficult). That will change in Lion, however, so if you can wait until then, this will become easier!
I'd like to create a custom widget wich is a combination of several (for example a list, a button and combobox)
How is your custom widget different to just placing those three things in the same view?
You could write your own NSView subclass. When it's created, it should create a list, a button and a combobox and add them as subviews to itself. Your NSView subclass should handle the logic of keeping them in sync or doing whatever it is you want them to do. Then, to use this combination control in Interface Builder, you place a Custom View and set its class (rightmost tab of the inspector) to your NSView subclass.
BTW, on a tangent, are you sure you mean combobox? Loads of people coming from Windows get this one wrong. A combobox is a combination of a menu and a text field: it allows the user to enter custom text that is not in the menu. If you just want a dropdown menu of choices (and the user can't enter a custom one), you use an NSPopupButton.
Secondly a typical cocoa developer uses external controls?
Yes, sometimes. Things like BWToolkit can be very useful. There's a lot more that are just floating around mailing lists as code snippets, rather than being cleaned up and put in a library. Search for what you need to do!