The Grid widget in Vaadin 8 & 10 offers a method to get a Set of the currently selected items: Grid::getSelectedItems.
In a similar vein, I would like to get a collection of the items that are currently visible to the user in the Grid. Say my Grid widget holds 10 items, but only 5 are viewable because the Grid widget is too short to display them all. I want to know which of the five can be seen by the user.
This is not trivial task, I have something similar, but not exactly this case before. First of all, I would I would create custom Layout component, e.g. by extending CssLayout in similar fashion as has been discussed here ( How to make UI receive scroll events ) in addition to reporting scroll events I would report the position of the layout on the viewport (see http://www.gwtproject.org/javadoc/latest/com/google/gwt/dom/client/Element.html ). Yes GWT and client side development is required.
I would use this layout as wrapper for the Grid, i.e. Grid would be in the layout. You could extend the Grid component as well. But I think doing the layout wrapper gives you nice tool that you can use with other components as well for which you need to determine, whether they are actually visible or not.
This way I can then calculate which portion of the layout is in the viewport. As you see, there are number of cases here, e.g. only bottom of the Grid or top of the Grid is visible. Then I need to know row-height, header height, etc. That enables me to calculate how many rows there are visible. I hope you get the idea. The outcome for the generic case will be rather lengthy piece of code when all possibilities are enumerated. This calculation you can do on server side.
Related
First of all, let me tell you that I am new in Xamarin.
I am facing a problem in rendering controls dynamically on UI.
Approach I am using is: Xamarin.iOS
I have list of Questions having different Question Types
I loop through all questions and render them according to the question type.
Client wants to have HTML in Question Title, so that he can add any type of html tags including images, links etc in HTML. (I cannot use ‘NSAttributedString’ because it doesn’t support all HTML tags)
I am not using AutoLayout
I think UIStackView is a new control which is not available for older versions
Problem is, when I render UIWebView for QuestionTitle, and other control (let us say UITextField) for simple input from user, I do not know about the exact content length of Title (which is HTML) and therefore, I set default height of UIWebView as ‘100’ and once WebView is loaded, I set the height of webview according to the content size height. While rendering control, I calculate the Y-axis for every control to be rendered. When WebView is loaded, its height gets shrunk or expanded according to the size of content and therefore, the preceding sibling’s y-axis remains there since we don’t know how much siblings are there whose y-axis should be adjusted. (Keep in mind we have multiple webviews, as we have more than 1 question).
Is there any way, we can position all controls automatically (Just like we have LinearLayout in Android)?
Is there any better approach I can follow in order to resolve this kind of blocker?
I will really appreciate your help in this problem.
I am starting to make my Vaadin web app responsive. Reading Vaadin docs, I managed to make a CssLayout flexible such that an image is shown either to the left of a text section or in a separate row depending on available width.
Now I want to make my login form flexible. By default, captions are moved to the left of the fields. How can I achieve that the captions are moved to the top of the fields when a certain width is reached? Is that even possible with FormLayout?
Can't really imagine that it is possible with CSS because the FormLayout is rendered as HTML table. If so, what is a simple alternative?
That is not possible with FormLayout. Structure of FormLayout is not flexible. Also there is not simple alternative for that. You can use CssLayout or create your own component container.
Starting point for this can be extending AbstractComponentContainer as described in Creating a simple component container
I would like to add an icon to the header of my data grid as it is done in Thunderbird.
There is an icon that is above the vertical scrollbar, no matter the position of the horizontal scrollbar. This icon allows the setup of the columns.
In Delphi there a lot of different grid components, that allow customizations and adding icons to there cells / header cells. But I could not find any component that has an area above the vertical scrollbar that is fixed, which when clicked allows some action. I could even use the VirtualTreeView component to emulate the grid, if it turns out to be easier to customize that component.
I am looking for some guidance on what need to be done to get that functionality.
Thanks,
Thomas
VirtualTreeView in Listbox mode would be nice, because of it's speed, great documentation and ease use in MVC-like patterns. Delphi tempts to store data in the visual components themselves, which letter causes troubles. While VTW allwos the same, it also allows to acutally separate data from GUI, and i like it.
But i am surprised by your claim "which when clicked allows some action.".
Even most basic components allow it:
http://docwiki.embarcadero.com/Libraries/XE2/en/Vcl.Grids.TCustomGrid.OnFixedCellClick
So could you make more detaiils, why you cannot use standard components ? with screenshot and editors, how u want it rendered, where you want to click and what kind of action should happen ?
Is it possible to add gui components to blackberry screen beginning from the bottom instead of the top ?
Thanks
A quick response would be no but let me explain why and suggest afew work arounds;
Screens don't actually handle the laying out of fields onto themselves, to do this they delcare a delegate manager which can be any type of manager, vertical, horizontal etc. The problem is all managers begin painting themselves from the top left. For a manager to paint fields starting from the bottom it would have to know exaclty where the bottom is located and add components up rather than down which goes against all the low level code inside the manager class. You can read more on managers in the BlackBerry API documentation.
You could still achieve an effect similar to this though by tweaking how you add fields and playing with field styles. For example consider this code:
add(new LabelField("field 1"));
add(new LabelField("field 2"));
This would give us the results;
field 1
field 2
because field 1 is drawn then field 2 below it. However if we were always to insert fields at the begining of our manager e.g. position 0 like so:
insert(new LabelField("field 1", FIELD_BOTTOM), 0);
insert(new LabelField("field 2", FIELD_BOTTOM), 0);
We would get the results;
field 2
field 1
Which is the results you'd expect from a screen described in your question.
I'm not really sure how you'd get the fields to paint to the bottom of a screen though, you could try researching the "position relative bottom" styles but I'm honestly unsure.
You are probably using a VerticalFieldManager, and the documentation on that says:
A vertical field manager lays out
fields top to bottom in a single
column.
So if you
manager.add(field1);
manager.add(field2);
manager.add(field3);
The order of the fields on the screen will be just that.
But you could do something like this:
Vector v = new Vector();
v.add(field1);
v.add(field2);
v.add(field3);
for(int i=v.size()-1;i>=0;i--) {
manager.add((Field)v.elementAt(i));
}
Sort of. You can use the Manager#insert(Field, int) method and always insert at the zero index. If you do this with a VerticalFieldManager, it would simulate a bottom-up adding of Fields to the Manager.
Some of the answers so far are to use Manager.insert(Field, int), and keep inserting at position 0. This will work, but the running time of the insert is linear in the number of elements already added to the manager. Meaning this solution will have an overall quadratic running time. Not a big deal if you're adding under 10 fields, but if you're planning on adding more than that, the insert overhead will be substantial.
If you can do the inserts top to bottom, by reordering the fields as Muger's solution suggests, the running time will be much improved.
Finally, you can write your own BottomUpVerticalFieldManager that does the layout the way you want. When you write your own manager, you can layout the fields in whatever way pleases you. In this case, it would be bottom to top. Writing your own manager may seem daunting, but it will give you considerable freedom in the future when trying to solve layout issues.
We have developed a software. In this software we are show and hiding a few controls on various input screens depending on various situations.
When we hid a control what happens is that the space occupied by that control is left as it is and layout looks very bad at times esp. in screens that have larger numbers of controls. Our client does not like this and has asked us to do something about this.
My question:
Is there some way by which we can create Fluid Layouts so that when a control is hidden the rest of the controls automatically adjusts themselves to fill the empty space left by the control hidden and when the control is show they should automatically make way for the control and adjust themselves accordingly.
I know we can achieve this by coding but that will require a lot of code in each screen for adjusting the layout. I am looking something which will reduce coding in each screen as there are 80+ screens.
Please suggest some way which is less error pron and can get rid of unnecessary coding in each input screen.
I think your best option is to use a component that handles the layout of your vcl controls on your form in runtime (depending on the conditions that you define). I recommend you try the Devexpress ExpressLayout Control
you can find two great demo videos here
ExpressLayout Control - How to Customize Layout Views
ExpressLayout Control - Create and Customize a Simple Layout
(source: devexpress.com)
You can check these features
Auto-Management - Control groups and individual control elements are automatically managed by the Layout Control. You never worry about pixel-by-pixel positioning.
Form auto-sizing - The form can be automatically resized to fit its contents best.
Bye.
Now, I'm not sure how complex layout you have, but I guess you can use TFlowPanel and/or TGridPanel for this. Flowpanel has a nice handling of components that change visiblity. I'm not sure how well gridpanel handles the same...
What kind of controls are you dynamically hiding, and what do you mean with auto fill space?
I do not know if it is as this simple: place controls on panels, and use align alTop/alClient/alBottom. When you hide a panel, all other panels will move automatically up.
One problem though: if you want to show a panel again, the order of panels can sometimes be screwed up... Can be fixed by manually setting .Top property, or "hide" by setting .Height := 1;
What I would do with a complex layout is actually split it up into several tabs. This has two advantages. It simplifies the form layout, and allows you to show and hide whole tabs depending on choices made in other tabs.
Raize Components have a TRzFlowPanel UI component. Does exactly what you're after.
Use TRzFlowPanel to put an empty flow panel on a form. The major difference between a traditional panel and a flow panel is the way in which controls are placed. With a traditional panel, you place a control (such as a button) in a specific location. You can freely move that control to any location within the panel using the mouse. In a flow panel, each control is placed in a specific location, regardless of where you place it with the mouse. The automatic location is controlled by the FlowStyle property. For example, using the default FlowStyle property of LeftRightTopBottom, the first control you add to the flow panel snaps to the top left corner. The second control that you add snaps next to the first control, and so on.