how to turn off log cat output after making release apk when minifyenabled is true in android

Question

First of all please dont take it as a duplicate question as I have tried all the solution from this forum but failed to get my answer.

From my gradle.build file I have made:

minifyenabled to true and then write this line of code in my project's proguard-rules.pro file:

-assumenosideeffects class android.util.Log {
    public static *** d(...);
    public static *** e(...);
    public static *** i(...);
    public static *** w(...);
    public static *** v(...);
}

but this doesnt change anything in my project, when I make a release version apk and run on my device all log still shows! Is there anything new that I have to do now?

Answer 1

-assumenosideeffects is skipped when -dontoptimize is set (relevant documentation), which I believe is the default for the standard ProGuard configuration file provided by Android.

If you'd like to use -assumenosideeffects then you will have to use the proguard-android-optimize.txt configuration file from the {your-sdk-dir}/tools/proguard/ directory. This will be also applied to any libraries which you use in your application project, so their logging will be stripped as well if you're worried about that.

As an alternative you could use a wrapper class for Android's Log, wrapping all calls in conditions checking the BuildConfig.DEBUG flag, which is nicer since you will have a single access point for these checks as opposed to littering them all over your classes.

It is however worth noting that for the latter solution you will not get a performance improvement for release builds, as if you have lots of logging where you concatenate strings for your messages these will still be evaluated at runtime for the method calls (even if they will never be printed out).

Answer 2

In the app I work on, we ended up using a different approach. We look carefully at our logging statements, most are used only during initial development. We remove those once a feature is done.

For the logging statements that we want to keep, we use this approach:

import com.mycompany.mypackage.BuildConfig;
import android.util.Log;

public class SomeClass {

    public void someMethod() {
        if (BuildConfig.DEBUG) {
            Log.i("SomeClass", "Some logging");
        }
    }
}

What happens is that the BuildConfig.DEBUG field is a public static final boolean that is generated by the build process. In release builds this boolean is generated as false, which means that you get if (false) { /* logging */ }. The java compiler is smart enough to see that this code will never run, and leaves it out of the Java byte code entirely. When this byte code is then dexed and put into the APK, the logging is simply not there.

We're not using the -assumenosideeffects marker at all.