View the log output of any app on iPhone or iPad

Here's another tip using the great libimobiledevice library http://www.libimobiledevice.org/, originally built to manage iOS devices on Linux.

This method shows you how you can view the log output (e.g. what you see in Xcode when running in debug mode) on any app, whether it's an AppStore build or an AdHoc build.

Some apps are more talkative than others - it all depends on how careful the developers were to remove log messages in release builds.

I find this most useful for debugging issues in release versions of our apps. If a user reports a sequence of actions causes a crash, you can try this out while watching the log from your app.

Here's how:

• Grab the libimobiledevice binary for Mac OS X from my github account athttps://github.com/benvium/libimobiledevice-macosx/zipball/master
• Follow the install instructions here:
  https://github.com/benvium/libimobiledevice-macosx/blob/master/README.md

Connect your device, open up Terminal.app and type:

idevicesyslog

Up pops a real-time display of the device's system log.

With it being a console app, you can filter the log using unix commands, such as grep


For instance, see all log messages from a particular app:

idevicesyslog | grep myappname

Install iPhone / iPad / iOS App IPA without iTunes or Xcode

Using the great libimobiledevice library http://www.libimobiledevice.org/, originally built to manage iOS devices on Linux, it's possible to do a bunch of cool things, including installing an app directly on a connected device without needing to use iTunes or Xcode.

Here's how:

• Grab the libimobiledevice binary for Mac OS X from my github account at https://github.com/benvium/libimobiledevice-macosx/zipball/master
• Follow the install instructions here:
  https://github.com/benvium/libimobiledevice-macosx/blob/master/README.md

Now connect your iDevice, open Terminal.app and type:

ideviceinstaller -i myApp.ipa

Note: Your IPA will need to have a valid code signature and mobileprovision file for the install to succed. This system is NOT a way around iOSs security!

AppCode Delegate Pattern Live Template

Here's a Live Template to generate a common delegate pattern in AppCode, JetBrain's Objective-C IDE.

Script to automatically create retina and non-retina versions of images

I often get sets of files from graphic designers for iOS apps. Ensuring that the standard and @2x versions of all the files are present and correct is a bit of a pain, for the artist and for myself. The number of times there's been a mispelling in one of the images has been.. well .. many.
Instead I now ask them to send only the retina versions of the images, without the @2x tag in the filename (this has caused confusion).

I then run this script on the whole folder of files, and out pops a folder containing all the files properly renamed and resized. I use the incredible useful 'sips' command-line application that comes with OSX.

The fiddly bit of this script was working out the new size of non-retina images. Yes, they're half the size, but sips doesn't support percentages.
Credit to (person on superuser.com who I'll find eventually) for the neat sed command to extract the pixel size from the output of sips.
Note: clearly the file extension part can be done better. But it works for me right now.

Get version number of live app on App Store in Phonegap app

A nice feature you might want to add to your iOS app is to notify the user when a new version is available on the App Store. Of course the user can go to the App Store manually and install the update, but we've noticed quite a few users don't do this very often. Some carefully-judged prompting is bound to help.

It turns out there's an API that Apple run that can return, in a handy JSON or JSONP format, the metadata for a particular app on the app store. This includes both the version number of the app, and even better, the 'what's new in this version' text.

You can use this information on your app's startup to check if a new version is available, and tell the user what's in it, and then finally, link them to the update page for the app.

Here's some bare-bones bits of example code to get you going. You'll need to know your app's Apple ID (e.g. 387022138). You can find this in the iTunes Connect interface). I'm also assuming that you're using jQuery or Zepto in your app.

The below also works in the browser.

// Alert the version number and release notes of an app.

    $.ajax({
        url:"http://itunes.apple.com/lookup?id=<APPLE ID HERE>&callback=?",
        success:function(data) {
            if (data && data.results && data.results.length) {
                alert(data.results[0].version);
                alert(data.results[0].releaseNotes);
            }
        }
    });

Here's the full list of data you might want to use:

Screengrab showing properties of the response from the API call. Click to view full size.

To open iTunes looking at your App's update page open the following URL:

itms-apps://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftwareUpdate?id=<APPLE ID HERE>&mt=8

How to link to unreleased App Store apps

For a client I'm making an app that comes in 'full' and 'lite' versions. The client wanted to have a button in the lite version that opens the full version in the App Store on the device.  Now this was a little bit tricky because both the full and lite versions were in progress and hadn't been released yet. They didn't even have names.. I needed to release both apps at the same time so testing the link worked seemed impossible.

The solution was to have the 'upgrade' button link to simply open an html page on a site I own in Safari on the device. Doing this meant I could alter what the link actually did at any time.

Once the client had set up the apps in iTune Connect, I asked for the Apple ID of the full version of the apps (shown in iTunes connect on the App Info Page).

I then updated the HTML page that was opened by the app to contain the following (replacing the 123456789 with the real app ID of course).

<script type="text/javascript">

window.location = "itms-apps://itunes.apple.com/app/id123456789?mt=8"

</script>

Now when that button is pressed, Safari flashes up briefly (but doesn't actually display the page) and then the App Store app opens and displays the app. Voila!

Ah, I hear you say. Can't I just use the app name rather than the Apple ID? Well, yes you can. Here's a load of different ways of linking to apps on the app store.

For me though, these options weren't so good as my solution because:

• There a fairly fiddly way the actual name is converted to a url-friendly name. Easy to get wrong.
• My app names weren't finalized at the time of writing anyway.
• If the client changes the name of the app, the link will break.

Vertically Centering Multi-Line text in CSS

There are many, many blog posts on this subject already, but I've struggled to get many of the methods to work so I'm saving this for posterity.

<div class="label">
    <div class="label-inner">
        foobar<br>baz
    </div>
</div>

.label {
    display: table;
    width: 300px;
    height: 200px;
    border: 1px solid black;
}

.label-inner {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
}

Result