I have a standard UITable. When the user scrolls through the rows and then clicks on one of the cells; they will be transfered to another view. There will be some process time from the tap of the cell to the new view. I would like to display a UIActivityIndicator in a view that over lays the center of the UITable. I am not sure though how to obtain the visible center of the UITable.
The code I have:
myView.center = self.tableView.center;
Puts it in the center of the UITable until I start scrolling further and further down. Then the UIActivityIndicator stays up at the top, so it appears UITableView.center does not represent the "Visible Center".
Any tips on how I can achieve this?
Thanks!
Flea
There are two ways to achieve this.
Either you add your activity indicator view to the same view holding the tableView and THEN they can have the same center:
UIView* superview = [tableView superview];
yourActivityIndicator.center = tableView.center;
[superview addSubview:yourActivityIndicator];
or you decide to add your monitor view to the tableView but then the center of this view must be calculated and will depend on the size of indicator view.
CGSize tSize = tableView.frame.size;
CGSize aSize = yourActivityIndicator.frame.size;
yourActivityIndicator.center = CGRectMake(
(tSize.width-aSize.width)*0.5,
(tSize.height-aSize.height)*0.5,
aSize.width,
aSize.height);
[tableView addSubview:yourActivityIndicator];
Put the activity indicator in the tableview's parent instead of in the tableview itself, then it won't scroll with the table view
Related
I am displaying the 3 cells at the same time in UICollectionView. How to force the user to horizontally scroll only one item at a time in UICollectionView?
This should be enough:
self.collectionView.pagingEnabled = YES;
Swift version:
self.collectionView.pagingEnabled = true
If you want your cells to be moved only one at a time then you need to set the frame of cell equals to the collection view and then set the collectionView's paging enabled as below,
[collectionView setPagingEnabled:YES];
or
collectionView.pagingEnabled=YES;
For example in Tweetbot's iPhone app. When you open up the app and new tweets come in, it will just be appended to the top of the UIScrollView and the current tweet you see did not get refreshed. How can I achieve the same thing effect?. Say I have a UIScrollView with a UIView added to the UIScrollView starting at origin 10,10.
I then downloaded a few items and I want to put it at 10,10.. so I basically need to shift this old item at 10,10 down right? If I do so then during that shifting user's will see it shifted, which is not the effect I want. Where as in Tweetbot's app it seems that nothing is being shifted around, it's just that you grow the area above the 10,10 and append new stuff's there.
How do I do this?
Basically I wanted to implement the insertRowAtIndexPath in a UIScrollView.
Will restate the question this way: how to add content to the top of a UIScrollView without moving the content that's already there (relative to it's current offset).
If this is the right question, the right answer is to do the add and shift down just as you suggested, but then scroll by the same height as added content, giving the illusion that the old content didn't move.
- (void)insertRowAtTop {
// not showing insert atIndexPath because I don't know how you have your subviews indexed
// inserting at the top, we can just shift everything down. you can extend this idea to
// the middle but it requires that you can translate from rows to y-offsets to views
// shift everything down
for (UIView *view in self.scrollView.subviews) {
if ([view isKindOfClass:[MyScrollViewRow self]]) {
MyScrollViewRow *row = (MyScrollViewRow *)view; // all this jazz so we don't pick up the scroll thumbs
row.frame = CGRectOffset(row.frame, 0.0, kROW_HEIGHT); // this is a lot easier if row height is constant
}
}
MyScrollViewRow *newRow = [[MyScrollViewRow alloc] initWithFrame:CGRectMake(0.0,0.0,320.0,kROW_HEIGHT)];
// init newRow
[self.scrollView addSubview:newRow];
// now for your question. scroll everything so the user perceives that the existing rows remained still
CGPoint currentOffset = self.scrollView.contentOffset
self.scrollView.contentOffset = CGPointMake(currentOffset.x, currentOffset.y + kROW_HEIGHT);
}
If you set the contentOffset without animating there wont be a visible scrolling animation. So if your new view is 200 points tall you can set the origin of the new view at (10,10) and the old view at (10,210) and set the contentOffset of the scroll view to (10,210) you should achieve the effect you intend. You'll also need to increase the contentSize of your scroll view to be big enough for all of the content it contains.
I'm using a UISegmentedControl as the headerview of a tableview. Now I want to add loading view (a view defined by myself) only covering the table cells but not my headerview. How do I achieve this?
You can add this view to the cell you want:
UITableViewCell *cell = [self tableView:self.tableView cellForRowAtIndexPath:indexPathOfCell];
[cell addSubview:view];
The simplest way to add the loading view would be like this
// get the frame of your table header view
CGRect headerFrame = headerView.frame;
// construct a frame that is the screen minus the space for your header
CGRect loadingFrame = [[UIScreen mainScreen] applicationFrame];
loadingFrame.origin.y += headerFrame.size.height;
loadingFrame.size.height -= headerFrame.size.height;
// use that frame to create your loading view
MyLoadingView *loadingView = [[MyLoadingView alloc] initWithFrame:loadingFrame];
// add your view to the window *
[[headerView window] addSubview:loadingView];
* Adding the view to the window may not be the best thing for your design, but since I don't know any of the details of your view hierarchy, this is the way that will always work.
Caution: If you do not cover up the segmented control, and it is enabled, the user may click on it and change the state of the app when you aren't expecting it - like when you're trying to load something for them. Be sure that you can cancel this loading view if the user changes the state of the app.
I am trying to change the look of the tableviewcells by adding columns. I know the normal tableview doesn't allow this. Can someone point me in the right direction to achieve something similar to the attached image? The basic functionality is to have a grid of cells. 3x3 and any of the 9 cells can be clicked and it opens another page. its similar to the image picker but instead of images it would be cells with subtitles etc.
http://www.bronron.com/apps/IpadMenu.jpg
Any ideas?
Thanks in advance.
I would recommend that you try using a UIScrollView instead of a UITableView for this.
Each item in your menu can be a UIImageView, or a UIButton which you add as subviews to your UIScrollView.
The following code can be insterted in viewDidLoad inside your view controller and assumes that you have setup your UISCrollView in interface builder, otherwise you would need to allocate your scroll view inside viewDidLoad.
The code will add a variable number of menu items to a UIScrollView with two columns. To deal with user input you can make all the menu items UIButtons which call associated IBAction methods, or in this case the menuItems are you views, so you can identify which menu item the user is touching by looking at the users touch location within the scroll view, and then carrying out the appropriate action based on this.
UIImageView *menuItem = nil;
//The x and y view location coordinates for your menu items
int x = 0, y = 0;
//The number of items you want in your menu
int numOfItemsToAdd = 10;
//The height and width of your menu items
int menuItemHeight = 50, menuItemWidth = 50;
//The content seize needs to refelect the number of menu items that will be added
//The hieght of the ocnten size is calclutated by multiplying the menu item height by the number of
//menu items devided by the number of menu items that fit across in the width of the view.
[scrollView setContentSize:CGSizeMake(320, menuItemHeight*numOfItemsToAdd];
for(int i=0; i<numOfItemsToAdd; i++){
if(i%2 == 0){//% the number of columns you want in your menu
x = 0;
if(i!=0)
y += menuItemHeight;
}else{
x = menuItemWidth;
}
menuItem = [[UIImageView alloc] initWithFrame: CGRectMake(x, y, menuItemWidth, menuItemHeight)];
//set the center of the menu item in the scroll superviews coordinate system
menuItem.center = CGPointMake(x, y);
//Add the name of the image you want for the menu item
//These strings could be stored in an array and retrieved in order
menuItem.image = [UIImage imageNamed:#"MyImage"];
//Finaly add the menu item to the scorll view
[scrollView addSubview:menuItem];
}
You can go for multi column grid table view layout , where you can define each and every row and column.
you can check this tutorial for Drawing a Grid in a iPhone UITableView – Tabular Cell Data
http://www.iphonedevx.com/?p=153
This is a completely custom view layout and IMHO, not really suitable for a table view. As with anything custom there are many ways to achieve what you want. Here's how I would approach this implementation myself. There may very well be some good open source implementations out there.
GridViewController : UIViewController
This is the top most view controller and has a UIScrollView containing 1 or more pages of GridView objects. This view controller would communicate with a dataSource that provides 0..N objects to display on the individual grid views.
GridView : UIView
Each grid view would be a custom UIViewSubclass that knows how to layout 0 to N objects as dictated by the data provided by the GridViewController dataSource. Each icon in the grid would be an appropriate UIView subclass, maybe UIButton or UIImageView or maybe custom depending on what it needs to look and act like.
More behavior would be added as needed to drag icons around, create new pages, persist state in the data model, etc etc.
Below shows the default position when you add a grouped table to a view? How do I push the entire grouped table down in the view?
(source: pessoal.org)
You can assign a transparent view with a fixed height to the tableHeaderView property of the tableView. This will push the table contents down by the height of the transparent view.
You can do this from your UITableViewController's viewDidLoad:
// force the table down 70 pixels
CGRect headerFrame = self.tableView.bounds;
headerFrame.size.height = 70;
UIView *header = [[UIView alloc] initWithFrame: headerFrame];
header.backgroundColor = [UIColor clearColor];
self.tableView.tableViewHeader = header;
[header release];
Look at the delagate to the UITableView.
You will find a property 'heightForHeaderInSection'.
For section 0 just make the header larger (default is 0) it will push the table down the view.
If you are moving the table down, you undoubtedly wish to use the space you gain to add UI elements.
At that point, consider building the page in IB. You can resize the table view to be where you like and put the UI elements above the table. You can use a UIViewController to manage the page and add the UITableViewDelegate/Datasource protocol methods so that you can wire the UITableView back to your view controller as a delegate... then you can also wire the other UI elements to the same view controller.
The simplest way to do it is probably just to modify the frame for the tableview. You'll need to get a reference to the tableview in your controller either through an IBOutlet or by finding the view in the view hierarchy OR you can change the frame in Interface Builder.
In code something like:
tableView.frame = CGRectMake(0.0, 200.0, 320.0, 280.0);
Would position the tableview down the screen and limit its height - the dimensions you use will be dependent on whether you had a tab bar on the view and things like that.
In interface build just select the tableview, then choose the Size inspector (the inspector tab with the ruler icon) and set the height and y offset to shift it down the view.