First of all, I am sorry that this is not a 'question that can be answered' like it is written in 'How to ask' section, but I think that stackoverflow is the place where I will get the best 'answers' so please help me with this one;
I have in mind to make some Flex application which will be used as some kind of (powerpoint) presentation.
My idea is to make some kind of template which will hold basic stuff like header, footer, and mainContent...
Header will be probably 'static' which means that it will hold some constant values (strings). Footer will have few static strings and an option to display current slide / total slides. Main content would be just some Canvas and I imagine that easiest way to make all my slides is to make a component (which will extend Canvas) for each slide so I will be able to 'design' each slide however I want...
The most important thing is that I should be able to define a transition between slides (some of Flex effects - Move, Fade, etc). And maybe even extend that option to some other Flex libraries (maybe like Distortion Effects or similar).
And finally I should be able to define how much 'steps' each slide has... For example, when you click next, slide can switch to next slide or it can stay on same slide and change some values inside of it (like changing graph values or something).
I started to make my application and for now I made an XML file which holds a title and effect definition for each slide. I made 3 AS classes which are header, footer and mainContent. I was playing around with effects and counting pages and such basic stuff and for now things seems fine... But I am stuck with 'implementing' my canvases (slide content) to each slide...
Nevertheless, I don't ask you to make some code for me... I just want to know if I get the idea correctly... I would need just few guidelines how to 'set-up' my application so it could have all those features I need =)
Thank you very much for any help really!
Cheers!
You seem to be going well with it. Have you considered using a view stack as slide holder?
<vbox>
<header/>
<viewstack>
<Slide/>
<Slide/>
</viewstack>
<footer/>
<hbox-with-navigation-buttons/>
</vbox>
The base class Slide extends Canvas
The Slide class describes (abstract) methods to go to next/prev step.
Viewstack listens for navigation button clicks and passes it to current slide and changes slides only if current slide has no more steps.
Bind the header property of viewstack.selectedItem to the header
Bind viewstack.selectedIndex to the page number in footer.
I'd use a viewstack as Amarghosh suggested, but then also create a base class or interface for each of your slides that has a 'stepForward()' and perhaps a 'stepBackward()' function. That way you'll know each of your items in your viewstack has those functions available for you to call, but each viewstack item can implement these functions differently.
You can use the hideEffect and showEffect properties of the viewstack's children to define cool transistion between slides. Something like this:
<!-- wipe transistion effects -->
<mx:WipeUp id="myWU" duration="300"/>
<mx:WipeDown id="myWD" duration="300"/>
<viewstack>
<Slide id="slide_1" showEffect="{myWU"}" hideEffect="{myWD}"/>
<Slide id="slide_2" showEffect="{myWU"}" hideEffect="{myWD}"/>
</viewstack>
Will cause the wipe effects to be played when you switch from slide 1 to slide 2.
Related
I am trying to create a profile menu for my polymer website, something on the lines of github.com
If you notice,there is a triangular tip at the top of the menu.I am trying to create a similar triangle at the top of paper-listbox.
The problem I am facing is that the triangle seems to hide as soon as it gets out of the boundaries of paper-listbox.
I have create a jsbin to demonstrate my problem: http://jsbin.com/samaloqowu/1/edit?html,console,output
If you change the top property of the triangle (say -16px), it hides when it gets out of the listbox region. Please help me solve this CSS issue.
Short answer : No you can't.
Explanation : Because the dropdown content get encapsulated in a slotted element that gets styled inside the shadowRoot of the custom element you try to modify the behavior. And the paper-menu-button doesn't actually gives you a way to directly customize the slotted.
But there is a trick ! You can access the slotted through classic javascript. Just alter your connectedCallback function and add this line :
...
connectedCallback() {
super.connectedCallback();
this.$.profileMenu.$.dropdown.querySelector('.dropdown-content').style.overflow = 'visible';
...
}
...
This should do the trick, I agree this looks totally awful and trying to force and change the initial behavior of an element is not really recommended but well it seems to work, just make some tests when the element gets in a new context to see if anything breaks.
UPDATE (22/09/2017) :
Thinking of that again, I think this is a terrible idea to change this overflow to visible, I guess the polymer team has set the overflow to auto because if the list get long and you force the height of the element, the list will flow and be visible which is not really a dropdown anymore, but more like a full list display and that will mess with the general design purpose of your app. IMO when you start trying to mess with the inner properties of a custom element it means this element doesn't quench your requirement, and that it's time to make your own, especially when you try to modify the design of a custom element that has a design already implemented.
I'm creating a context menu for certain elements using a PopupPanel; the menu itself is going to be fairly large and complex. What I'm looking to do is to have a list of buttons, plus an image and some text, related to the element clicked.
My problem is that I'd like the buttons to always display directly under the clicked element, because that's convenient for the user; the issue is that when PopupPanel is near the edges of the screen, it automatically changes position to be fully visible, not aligning its left side to the element as usual. I like this behavior, but it moves the position of the buttons away.
So what I'd like to happen is: normally the buttons are on the left of the panel, the other stuff is to the right. When the panel is close to the right of the screen, I'd like the buttons to instead be on the right (and thus under the clicked element) and the other stuff on the left.
Is there a clever way to do this, either in GWT or better yet, using only CSS? PopupPanel itself doesn't seem to tell you when it's going to get flipped, sadly. The only solution I currently have is to manually check the position and width of the popup before showing it and adjust accordingly, but I'm hoping there's a better solution.
Here is what I suggest (based on my own implementation of a similar use case):
Have the position callback implementation accept references (in constructor) on:
PopupPanel element
element on which user right cliked
the content you put in the PopupPanel
Replicate (I know this not DRY but implementation is package private) the code from default position callback
When opening to the right invoke a method that changes the layout of your content (CSS based or otherwise)
I hope it helps. If you find something better let me know.
i need some pointers here because i don't really know what to look for.
The project is in gwt and is using gwtquery.
I have this page with some elements and when the mouse overs an element it changes showing additional infos, let's call it header. When the mouse goes out of the header (which has some buttons so it need to stay visible once shown) it returns invisible.
The problem is that when the header is made visible all the elements of the page change position because my element changes in dimension. What i wish to do is to keep the element in the same position and overlap the header over everything with z-index.
It's not about GWT at first hand. It's mostly about general concepts of elements positioning and layout building for html pages. You should start from something like http://www.w3schools.com/Css/css_positioning.asp
And then find the appropriate tools in GWT framework or in third party libraries that are available.
I'm trying to make a Flex (Advanced)DataGrid component with some mechanism where the user can toggle the visibility of the columns. I've crudely implemented this by reading in the columns into the right-click menu, and when a column name is selected here, the visibility is toggled. It works, but it's not the most elegant solution.
Specifically, I'm trying to emulate the "datagrid" that Mozilla Thunderbird uses to display emails. Here is an image:
In the upper right, there is an icon over the scroll bar. If there is no scrollbar, the icon remains in the same place. When clicking the icon, it opens up a menu that shows all the possible columns, with the visible ones having a check mark next to them, like this:
Also, the scroll bar always appears under this button, never "pushing" it over into it's own column.
I'd like to re-create this in Flex. I believe the menu part and creating a column with a button headerRenderer is easy enough. But I can't figure out how (if at all possible) to do this with the scrollbar, because the scrollbar always seems to be "its own column". Any ideas or help would be appreciated. Thank you.
Ian
One dirty solution comes to mind. Create a component based on Canvas, then add an AdvancedDataGrid by overriding createChildren. Override updateDisplayList as well and add a button like the one in Thunderbird to the upper right of the Canvas. This will cause the button to appear over the DataGrid. Problemo solved?
I've noticed that the default behaviour for a DataGrid's vertical scroll bar is to scroll one row at a time. This is all well and good when the rows are all uniform and small (e.g. displaying a single line of text), but gets really ugly as soon as you have rows with variable heights.
I'm curious, is there a way to make DataGrid scrolling "smooth"? For instance, is there a way to have the DataGrid scroll by a set number of pixels, lines of text, etc. rather than scrolling one row at a time?
So far, the only solution I've managed to come up with is to place the DataGrid in a Canvas and have the Canvas do the scrolling instead of the DataGrid. The issue with this approach, though, is that as soon as the Canvas scrolls far enough, the DataGrid headers scroll off-screen. Ideally, I'd like to get the smooth-scrolling nature of the Canvas, but also keep the DataGrid headers visible. Is that possible?
The way that ItemRenderer's work in Flex 3 makes smooth scrolling difficult to achieve. Basically Flex recycles item renderers scrolled off of the top of the list as the display objects used for new data at the bottom of the list. Adobe's implementation of most list components in Flex 3 creates and adds these items as they come on to the screen rather than just off the screen, so they "pop in" and smooth scrolling isn't available. I'm not sure why they couldn't have done it in a similar manner for items +/- one position above or below the current scroll pane, but they didn't, and we're stuck with sticky scrolling by default.
Work-arounds do exist, though the one you've noted (dropping the datagrid into a canvas) negates the display-object saving intention of item renderers and incurs a performance cost. This will be fixed for most list-based Flex components in Flex 4, though it won't be fixed immediately for DataGrid. The DataGrid / AdvancedDataGrid component is maintained by a separate team based in India, last time I heard, and so it tends to be a bit behind the rest of the SDK.
I'd recommend trying something similar to this implementation of a smooth-scrolling list by Alex Harui. I'm not sure exactly how well it'd work for DataGrid or AdvancedDataGrid, but this is the most intuitive technique I can think of for making the list scroll correctly.
Try this... It's still based on Alex's code that was mentioned above. His should still be a great start for removing the snap-to-row behavior. Original source:
http://blogs.adobe.com/aharui/2008/03/smooth_scrolling_list.html
Alex's original some code for smooth vertical scrolling but that was not an issue I had with the DataGrid. It was smooth scrolling horizontally that I needed. I am using the DataGrid in an unorthodox manner for analyzing plain text reports output by our database (great way of providing visual feedback on a document). The code below allows content to go off screen and the user can scroll without that snap-to-column behavior.
You can adapt this to use the same math routines for vertical scrolling and then it will make scrolling possible and ignore the snap to row behavior. In particular switch the usage of the listContent.move method to move the contents vertically and use a inverse of the rounded pixel value you calculate from the vertical scroll bar (as opposed to my using the horizontal).
This method is bit simpler than Alex's method from the link above - a lot less code so try adapting and see how it works.
override protected function scrollHandler(event:Event):void
{
// Override the default scroll behavior to provide smooth horizontal scrolling and not the usual "snap-to-column" behavior
var scrEvt:ScrollEvent = event as ScrollEvent;
if(scrEvt.direction == ScrollEventDirection.HORIZONTAL) {
// Get individual components of a scroll bar for measuring and get a horizontal position to use
var scrDownArrow:DisplayObject = horizontalScrollBar.getChildAt(3);
var sctThumb:DisplayObject = horizontalScrollBar.getChildAt(2);
// I replaced maxHorizontalScrollPosition in Alex's code with "1300" to fix my exact application. In other situations you may finding using some property or different value is more appropriate. Don't rely on my choice.
var hPos:Number = Math.round((sctThumb.y - scrDownArrow.height) / (scrDownArrow.y - sctThumb.height - scrDownArrow.height) * 1300);
// Inverse the position to scroll the content to the left for large reports
listContent.move(hPos * -1, listContent.y);
}
// Go ahead and use the default handler for vertical scrolling
else {
super.scrollHandler(event);
}
}