Comments on: Android application backwards compatibility

By: Ondrej Cermak

Ondrej Cermak — Wed, 11 May 2011 19:16:25 +0000

Thanks for that wrap class trick. I was stuck with reflection which is too slow for what I need to do…

By: Martin

Martin — Fri, 06 May 2011 10:01:29 +0000

Thanks!! Very useful, you just saved me from stripping out loads of functionality from an app I am working on that has to support all the way back to 1.1, works nicely

By: Edwin Evans

Edwin Evans — Mon, 03 Jan 2011 00:28:01 +0000

Thanks!! Just what I needed, now I’ll release w/multi-touch for Bubbles Deluxe

By: Nona Mills

Nona Mills — Wed, 22 Dec 2010 17:20:21 +0000

“Simply referencing the class name somewhere in the code does not count as class use, and does not produce a class verification.” Unfortunately, this doesn’t appear to be the case with 1.6 (see error below). I have a program that conditionally uses TrafficStats, which is only available on 2.2. I test BUILD.VERSION.SDK before referencing TrafficStats, but this causes the program to crash running on 1.6 when the class that contains the conditional reference to TrafficStats is loaded. Strangely, when running on 2.1, it behaves as expected. E/dalvikvm( 1980): Could not find class ‘android.net.TrafficStats’, referenced f rom method com.iPass.MobileConnect.Wlan.WiFiManager.logTrafficStats W/dalvikvm( 1980): VFY: unable to resolve new-instance 45 (Landroid/net/TrafficS tats;) in Lcom/iPass/MobileConnect/Wlan/WiFiManager; W/dalvikvm( 1980): VFY: rejecting opcode 0×22 at 0x000a W/dalvikvm( 1980): VFY: rejected Lcom/iPass/MobileConnect/Wlan/WiFiManager;.log TrafficStats ()V W/dalvikvm( 1980): Verifier rejected class Lcom/iPass/MobileConnect/Wlan/WiFiMan ager;

By: Mitja

Mitja — Tue, 07 Dec 2010 09:01:51 +0000

Thank you for the article. Was very helpful! Now my app works also on 1.6

By: Pedro

Pedro — Wed, 22 Sep 2010 19:47:37 +0000

“Simply referencing the class name somewhere in the code does not count as class use, and does not produce a class verification.”

Unfortunately, this doesn’t appear to be the case with 1.6 (see error below). I have a program that conditionally uses TrafficStats, which is only available on 2.2. I test BUILD.VERSION.SDK before referencing TrafficStats, but this causes the program to crash running on 1.6 when the class that contains the conditional reference to TrafficStats is loaded. Strangely, when running on 2.1, it behaves as expected.

E/dalvikvm( 1980): Could not find class ‘android.net.TrafficStats’, referenced f
rom method com.iPass.MobileConnect.Wlan.WiFiManager.logTrafficStats
W/dalvikvm( 1980): VFY: unable to resolve new-instance 45 (Landroid/net/TrafficS
tats;) in Lcom/iPass/MobileConnect/Wlan/WiFiManager;
W/dalvikvm( 1980): VFY: rejecting opcode 0×22 at 0x000a
W/dalvikvm( 1980): VFY: rejected Lcom/iPass/MobileConnect/Wlan/WiFiManager;.log
TrafficStats ()V
W/dalvikvm( 1980): Verifier rejected class Lcom/iPass/MobileConnect/Wlan/WiFiMan
ager;

By: Guy Siverson

Guy Siverson — Tue, 03 Aug 2010 14:47:30 +0000

“I am an Android application developer. ”

I just had too. LOL – After all, you started this great post with that request.

The truth is I’m a mere user of what other people develop. From the user side of the coin I don’t like it when developers don’t make items backward compatible. What reasons are there for not making applications backward compatible?

I’m admittedly on the other side of the coin on this one, but certainly curious none the less.

By: Artem

Artem — Wed, 23 Jun 2010 14:27:19 +0000

This is exactly workaround that I googled for!

By: Alex

Alex — Wed, 23 Jun 2010 10:15:37 +0000

Very nice trick. The advantage of using java reflection is that one can then make an ant-build target which compiles against the old SDK-version (the version listed in minSdk), and if it compiles against the minSDK version, well then at least we probably havn’t accidentily started using new non-minSDK methods since our last release.

By: Daniel

Daniel — Sun, 06 Jun 2010 18:01:16 +0000

Thank you! Had been trying different solutions for over an hour when I found this.