Develop Reference

Is it necessary to perform API if-else check when using AppCompat

Previously, I'm using SherlockActionBar library. The following code will work, across Android 2.3 till Android 5.
this.searchMenuItem.collapseActionView();
However, after migrating to AppCompat, we need to migrate to the following code
MenuItemCompat.collapseActionView(JStockFragmentActivity.this.searchMenuItem);
When I look at the documentation http://developer.android.com/guide/topics/ui/actionbar.html#ActionView, it states that
On API level 11 or higher
Get the action view by calling getActionView() on the corresponding
MenuItem:
menu.findItem(R.id.action_search).getActionView()
I was wondering, is it necessary that I need to write my migrated code in the following way?
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
this.searchMenuItem.collapseActionView();
} else {
MenuItemCompat.collapseActionView(this.searchMenuItem);
}

Android app for all devices

I'm working on an app that is targeted for version 2.3 so that it will run on my sister's phone. However, I can run 4.0 on my phone. I want to add some swipe animations and such but I don't run the animations to run on her phone.
Is this even possible?

Yes, simply put the API specific code in a if/else block, so it is only called when the system supports it:
Like this:
if (currentapiVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
//do things that are only supported on JellyBean
} else {
//do the other stuff
}

You can use a ViewPager and FragmentPagerAdapter to provide swipe functionality among various Fragments. All of which are available in the support library.
ViewPager(Note, don't do anything with the ActionBar, as they are not yet in the support library):
http://developer.android.com/reference/android/support/v4/view/ViewPager.html
FragmentPagerAdapter(pretty much the example code you will need):
http://developer.android.com/reference/android/support/v13/app/FragmentPagerAdapter.html
Fragment:
http://developer.android.com/reference/android/support/v4/app/Fragment.html

Conditional compiling in Android?

Is there any kind of conditional compiling for Android?
I had to make my project for Android 3 (API 11) just because ExifInterface has almost no useful attributes in Android 2.3 (API 10), despite the fact that it appeared in API 5 (!!??). I don't want to restrict my app to ICS users.
Thanks!

You can check dynamically the current API version of the device and do different stuff depending on that:
if(Build.VERSION.SDK_INT < 14) {
// Crappy stuff for old devices
}
else {
// Do awesome stuff on ICS
}
But be careful that if you need to instantiate classes that are not available for all APIs then you should do it in a runnable or in a separate wrapper class, e.g:
if(Build.VERSION.SDK_INT < 14) {
// Crappy stuff for old devices
}
else {
// Do awesome stuff on ICS
new Runnable() {
new AmazingClassAvailableOnICS();
(...)
}.run();
}

import android.annotation.TargetApi;
and then use annotations:
#TargetApi(11)
public void methodUsesAPI11()
{
...
Using this trick does a very simple thing: it allows compiling some code which contains API level 11 calls (classes, methods, etc) and still set android:minSdkVersion="8" in the manifest. Nothing more, nothing else.
The rest is up to you. You must check platform version before you call methodUsesAPI11() or you handle exceptions in order to prevent app crash and perform other action on older platforms.

Checking Build.VERSION.SDK_INT or using annotations should suffice, however, this link I'd bookmarked might be relevant to your case:
http://android-developers.blogspot.com/2010/07/how-to-have-your-cupcake-and-eat-it-too.html?m=1
You can use what they describe there to have classes that may not be compatible, but will never be loaded. It's not conditional compilation, but it may be what you need, however, it is a bit more complex.

Action Bar Sherlock has deprecated methods

I downloaded the ActionBarSherlock version 4.1.0.0, and added a the Android Project library into Eclipse 4.2 on my Win7 java 1.6 update 24 machine. I used an Eclipse Project Build Target of Android 4.1 in Project | Properties | Project Build Target. I want to incorporate the ActionBar functionality into an existing app that has minSdkVersion="7". I noted the code from the ActionBarSherlock library appears to have some deprecated methods, and an error:
Example 1: ActionBarContainer.java, ActionBarContextView.java, ScrollingTabContainerView.java - uses setBackgroundDrawable - The method setBackgroundDrawable(Drawable) from the type View is deprecated
public ActionBarContainer(Context context, AttributeSet attrs) {
super(context, attrs);
setBackgroundDrawable(null);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.SherlockActionBar);
mBackground = a.getDrawable(R.styleable.SherlockActionBar_background);
mStackedBackground = a.getDrawable(
R.styleable.SherlockActionBar_backgroundStacked);
if (getId() == R.id.abs__split_action_bar) {
mIsSplit = true;
mSplitBackground = a.getDrawable(
R.styleable.SherlockActionBar_backgroundSplit);
}
a.recycle();
setWillNotDraw(mIsSplit ? mSplitBackground == null :
mBackground == null && mStackedBackground == null);
}
Quick fix shows as Add #SupressWarnings 'deprecation' for ActionBarContainer
Example 2:
IcsProgressBar.java uses animationResolution which shows as deprecated, same quick fix as above
private static final int[] ProgressBar = new int[] {
...
android.R.attr.animationResolution
Also, I have an error in ActivityChooserView.java:
private static class SetActivated {
public static void invoke(View view, boolean activated) {
view.setActivated(activated);
}
}
Error is on SetActivated - Call requires API 11 (current min is 7). This makes sense based on the manifest:
<uses-sdk android:minSdkVersion="7" android:targetSdkVersion="15"/>
Shouldn't API 7 be fine, since Action Bar Sherlock should work at at Andriod 2.x? Have others experienced this, and if so, what is the recommended action? Supress/ignore the deprecation? What about the error on SetActivated? I reviewed the readme and did some net searches but did not come up with anything on this. Thanks for any suggestions.
Thanks!

It is just fine. The code is 2.x compatible and even some methods are deprecated as of 4.x, they are still there. It also do not mean on 4.x these deprecated methods will be used. The source is 2.x-4.x so there's no other way (not to mention reflection, but that'd hurt performance, and is for now not necessary). So it is safe to just ignore this. It would probably be better to turn depreciation off for certain files but it is not there. So do not worry.

This is doesn't really answer the question but I ran into the same issue when I had to have a minSdkVersion 9 and I wanted to have ActionBarSherlock but I was getting the same error of the actionBar requires minSdkVersion 11.
Apparently in ADT 21.1 you make a values-v11/styles.xml and put the actionBar in there.
https://code.google.com/p/android/issues/detail?id=48283

Strategies for Honeycomb & backward compatibility

So we've seen the preview sdk and the neat new stuff like ActionBar and Fragments. Making a lot of method calls will be unavoidable to make use of these, so what strategies are there for maintaining 1 version of the app, which will let me use all the snazzy new stuff but also work on devices running 2.3 or below? My app targets 1.5 - 2.3 at the moment.

The same fragment APIs are now available as a static library for use with older versions of Android; it's compatible right back to Android 1.6.
There are a few tricks you can use to see if the various new APIs are available to your app. Generally speaking, you'll probably want to create two alternative sets of Activities, one that uses the fancy new APIs (ActionBar, Animators, etc.) -- and another set that don't.
The following code shows how you can use reflection and exception catching to determine the availability of the Fragment APIs, and version checking to confirm if the other Honeycomb APIs are available.
private static boolean shinyNewAPIsSupported = android.os.Build.VERSION.SDK_INT > 10;
private static boolean fragmentsSupported = false;
private static void checkFragmentsSupported() throws NoClassDefFoundError {
fragmentsSupported = android.app.Fragment.class != null;
}
static {
try {
checkFragmentsSupported();
} catch (NoClassDefFoundError e) {
fragmentsSupported = false;
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent startActivityIntent = null;
if (!shinyNewAPIsSupported)
startActivityIntent = new Intent(this, MainNonActionBarActivity.class);
else
startActivityIntent = new Intent(this, MainActionActivity.class);
startActivity(startActivityIntent);
finish();
}
Generally speaking you can use the same layout definitions. Where Fragments are available you'll inflate each layout within a different Fragment, where they aren't you'll probably want to use <include> tags to embed several of them into a more complex Activity layout.
A more detailed work through of how to write the code to support backwards compatibility on Honeycomb can be found here: http://blog.radioactiveyak.com/2011/02/strategies-for-honeycomb-and-backwards.html

Conveniently, Google's Dianne Hackborne has posted a blog entry covering this exact topic. Google say they'll be providing static libraries so older versions of Android will also be able to use fragments.

You might find Reto Meier's article on backwards-compatibility useful, specifically the section headed "Dealing with missing classes".
I've yet to look at the Honeycomb SDK myself but I, like you, am hoping it's pretty easy and hassle-free to make use the new features without jeopardising compatibility with older devices.

Well google just announced honeycomb will be tablet only: http://www.pcmag.com/article2/0,2817,2379271,00.asp
So if your device is meant for mobile only this may not even be an issue.

Official Android sample that will help you achieve ActionBar from 1.6 to 4.x