How to migrate applications for iphone 5 resolution

The new iPhone 5 display has a new aspect ratio and a new resolution (640 x 1136 pixels).

To make applications "universal" for both the older displays and the new widescreen aspect ratio follow the following steps:

1. Download and install latest version of Xcode.
2. Set a 4-inch launch image for your app. This is how you get 1136 px screen height (without it, you will get 960 px with black margins on top and bottom).
3. Test your app, and hopefully do nothing else, since everything should work magically if you had set auto resizing masks properly.
4. If you didn't, adjust your view layouts with proper auto resizing masks or look into Auto Layout if you only want to support iOS 6 going forward.
5. If there is something you have to do for the larger screen specifically, then it looks like you have to check height of [[UIScreen mainScreen] bounds] (or applicationFrame, but then you need to consider status bar height if it's present) as there seems to be no specific API for that.

Example:

CGRect screenBounds = [[UIScreen mainScreen] bounds];
if (screenBounds.size.height == 568) {
    // code for 4-inch screen
} else {
    // code for 3.5-inch screen
}

Also note: The auto-rotation API has changed completely, take a look at that as well if your application supports any rotation other than default.

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Applying CSS to an iframe

There are two different things here: the style of the iframe block and the style of the page embedded in the iframe. You can set the style of the iframe block the usual way:

<iframe name='iframe1' id="iframe1" src="empty.htm" frameborder="0" border="0" cellspacing="0" style="border-style: none;width: 100%; height: 120px;"></iframe>

The style of the page embedded in the iframe must be either set by including it in the child page:

<link type="text/css" rel="Stylesheet" href="Style/simple.css" />

Or it can be loaded from the parent page with Javascript:

var cssLink = document.createElement("link") 
cssLink.href = "style.css"; 
cssLink .rel = "stylesheet"; 
cssLink .type = "text/css"; 
frames['frame1'].document.body.appendChild(cssLink);

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HTML: Removing spaces between inline-block elements

Given this HTML:

<p>
    <span> Foo </span>
    <span> Bar </span>
</p>

and this CSS:

span { 
    display:inline-block;
    width:100px;
}

as a result, there will be a 4px wide space between the SPAN elements. Demo: http://jsfiddle.net/dGHFV/

I understand why this happens, and I also know that I could get rid of that space by removing the white-space between the SPAN elements in the HTML source code, like so:

<p>
    <span> Foo </span><span> Bar </span>
</p>

However, I was hoping for a CSS solution that doesn't require the HTML source code to be tampered with.

I know how to solve this with JavaScript - by removing the Text nodes from the container element (the paragraph), like so:

// jQuery
$('p').contents().filter(function() { return this.nodeType === 3; }).remove();

Answer:

Since this answer has become rather popular, I'm rewriting it significantly.

Let's not forget the actual question that was asked:

How to remove the space between inline-block elements? I was hoping for a CSS solution that doesn't require the HTML source code to be tampered with. Can this issue be solved with CSS alone?

It is possible to solve this problem with CSS alone, but there are no completely robust CSS fixes.

The solution I had in my initial answer was to add font-size: 0 to the parent element, and then declare a sensible font-size on the children.

http://jsfiddle.net/thirtydot/dGHFV/1361/

This works in recent versions of all modern browsers. It works in IE8. It does not work in Safari 5, but it does work in Safari 6. Safari 5 is nearly a dead browser (1.49%, July 2013).

Most of the possible issues with relative font sizes are not complicated to fix.

However, while this is a reasonable solution if you specifically need a CSS only fix, it's not what I recommend if you're free to change your HTML (as most of us are).

This is what I, as a reasonably experienced web developer, actually do to solve this problem:

<p>
    <span>Foo</span><span>Bar</span>
</p>

Yes, that's right. I remove the whitespace in the HTML between the inline-block elements.

It's easy. It's simple. It works everywhere. It's the pragmatic solution.

You do sometimes have to carefully consider where whitespace will come from. Will appending another element with jQuery add whitespace? No, not if you do it properly.

Let's go on a magical journey of different ways to remove the whitespace, with some new HTML:

<ul>
    <li>Item 1</li>
    <li>Item 2</li>
    <li>Item 3</li>
</ul>

You can do this, as I usually do:

<ul>
    <li>Item 1</li><li>Item 2</li><li>Item 3</li> 

</ul>

http://jsfiddle.net/thirtydot/dGHFV/1362/

Or, this:

<ul>
    <li>Item 1</li
    ><li>Item 2</li
    ><li>Item 3</li>
</ul>

Or, use comments:

<ul>
    <li>Item 1</li><!--
    --><li>Item 2</li><!--
    --><li>Item 3</li>
</ul>

Or, you can even skip certain closing tags entirely (all browsers are fine with this):

<ul>
    <li>Item 1
    <li>Item 2
    <li>Item 3
</ul>

Now that I've gone and bored you to death with "one thousand different ways to remove whitespace, by thirtydot", hopefully you've forgotten all about font-size: 0.

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CSS: How to align horizontally one div inside another div

How do I horizontally center a div in a div with CSS (if it's possible at all)? The outer div has 100%:

<div id="outer" style="width:100%">  
    <div id="inner">Foo foo</div>
</div>

In this example the outter div have 100% width, to align horizontally the inner div we can apply this code in the inner div:

#inner {
    width: 50%;
    margin: 0 auto;
}

Of course, you don't have to set the width to 50%. Any width less than the containing div will work. The margin: 0 auto is what does the actual centering.

If you are targeting IE8+, it might be better to have this instead:

#inner {
    display: table;
    margin: 0 auto;
}

It will make the inner element center horizontally and it works without setting a specific width.

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Android: Unfortunately MyApp has stoped

The Problem

Your application quit because an uncaught RuntimeException was thrown.
The most common of these is the NullPointerException.

How to solve it?

Every time an Android application crashes (or any Java application for that matter), a Stack trace is written to the console (in this case, logcat). This stack trace contains vital information for solving your problem.

Android Studio

In the bottom bar of the window, click on the Android button. Alternatively, you can press alt+6. Make sure your emulator or device is selected in the Devices panel. Next, try to find the stack trace, which is shown in red. There may be a lot of stuff logged into logcat, so you may need to scroll a bit. An easy way to find the stack trace is to clear the logcat (using the recycle bin on the right), and let the app crash again.

Eclipse

In the top right corner, click the DDMS button. If it is not there, you might need to add it first using the Open Perspective button to the left of the Java button. You will find the logcat pane at the bottom. First, make sure your device is selected in the topleft devices panel. Next, try to find the stack trace, which is shown in red. Again, there may be a lot of stuff logged into logcat, so you may need to scroll a bit. An easy way to find the stack trace here is to clear the logcat (using the clear log button on the top right), and let the app crash again. You should also click on the package name of your app, if it is not already selected. This will filter out only the log message made by your app.

I have found the stack trace, now what?
Yay! You're halfway to solving your problem.
You only need to find out what exactly made your application crash, by analyzing the stack trace.

I still can't solve my problem!
If you've found your Exception and the line where it occurred, and still cannot figure out how to fix it, don't hesitate to ask a question on StackOverflow.

Try to be as concise as possible: post the stack trace, and the relevant code (e.g. a few lines up to the line which threw the Exception).

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Angular JS: How to pass variables between controllers

One way to share variables across multiple controllers is to create a service and inject it in any controller where you want to use it.

Simple service example:

angular.module('myApp', [])
    .service('sharedProperties', function () {
        var property = 'First';

        return {
            getProperty: function () {
                return property;
            },
            setProperty: function(value) {
                property = value;
            }
        };
    });

Using the service in a controller:

function Ctrl2($scope, sharedProperties) {
    $scope.prop2 = "Second";
    $scope.both = sharedProperties.getProperty() + $scope.prop2;
}

This is described very nicely in this blog (Lesson 2 and on in particular).

I've found that if you want to bind to these properties across multiple controllers it works better if you bind to an object's property instead of a primitive type (boolean, string, number) to retain the bound reference.

Example: var property = { Property1: 'First' }; instead of var property = 'First';.

UPDATE: To (hopefully) make things more clear here is a fiddle that shows an example of:

Binding to static copies of the shared value (in myController1)

• Binding to a primitive (string)
• Binding to an object's property (saved to a scope variable)

Binding to shared values that update the UI as the values are updated (in myController2)

• Binding to a function that returns a primitive (string)
• Binding to the object's property
• Two way binding to an object's property

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Objective-C: How to make UIText move up when keyboard is visible

With the iPhone SDK:

I have a UIView with UITextFields that brings up a keyboard. I need it to be able to:

Allow scrolling of the contents of the UIScrollView to see the other text fields once the keyboard is brought up

Automatically "jump" (by scrolling up) or shortening

I know that I need a UIScrollView. I've tried changing the class of my UIView to a UIScrollView but I'm still unable to scroll the textboxes up or down.

Do I need both a UIView and a UIScrollView? Does one go inside the other? [EDIT: I now know that you want a UIView inside of a UIScrollView, and the trick is to programatically set the content size of the UIScrollView to the frame size of the UIView.]

Then what needs to be implemented in order to automatically scroll to the active text field?

Ideally as much of the setup of the components as possible will be done in Interface Builder. I'd like to only write code for what needs it.

Note: the UIView (or UIScrollView) that I'm working with is brought up by a tabbar (UITabBar), which needs to function as normal.

Edit: I am adding the scroll bar just for when the keyboard comes up. Even though it's not needed, I feel like it provides a better interface because then the user can scroll and change textboxes, for example.

I've got it working where I change the frame size of the UIScrollView when the keyboard goes up and down. I'm simply using:

-(void)textFieldDidBeginEditing:(UITextField *)textField { 
    //Keyboard becomes visible
    scrollView.frame = CGRectMake(scrollView.frame.origin.x, 
                     scrollView.frame.origin.y, 
scrollView.frame.size.width,
scrollView.frame.size.height - 215 + 50);   //resize
}

-(void)textFieldDidEndEditing:(UITextField *)textField {
   //keyboard will hide
    scrollView.frame = CGRectMake(scrollView.frame.origin.x, 
       scrollView.frame.origin.y, 
     scrollView.frame.size.width,
      scrollView.frame.size.height + 215 - 50); //resize
}

However this doesn't automatically "move up" or center the lower text fields in the visible area, which is what I would really like.

Solution

1. You will need a scroll view if the contents you have now does not fit in the iPhone screen. (If you are adding the scroll view just to make the textfield scroll up when keyboard comes up, then it's not needed.)
2. For showing the textfields without being hidden by the keyboard, the standard way is to move up/down the view having textfields whenever the keyboard is shown.

#define kOFFSET_FOR_KEYBOARD 80.0

-(void)keyboardWillShow {
    // Animate the current view out of the way
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)keyboardWillHide {
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
    if ([sender isEqual:mailTf])
    {
        //move the main view, so that the keyboard does not hide it.
        if  (self.view.frame.origin.y >= 0)
        {
            [self setViewMovedUp:YES];
        }
    }
}

//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3]; // if you want to slide up the view

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        // 1. move the view's origin up so that the text field that will be hidden come above the keyboard 
        // 2. increase the size of the view so that the area behind the keyboard is covered up.
        rect.origin.y -= kOFFSET_FOR_KEYBOARD;
        rect.size.height += kOFFSET_FOR_KEYBOARD;
    }
    else
    {
        // revert back to the normal state.
        rect.origin.y += kOFFSET_FOR_KEYBOARD;
        rect.size.height -= kOFFSET_FOR_KEYBOARD;
    }
    self.view.frame = rect;

    [UIView commitAnimations];
}


- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    // register for keyboard notifications
    [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillShow)
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillHide)
                                             name:UIKeyboardWillHideNotification
                                           object:nil];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    // unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillHideNotification
                                           object:nil];
}

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