Debug logging class that enables ProGuard to remove all logging artifacts from the code

Dbug.java

/*
 * Copyright (C) 2011 Glowworm Software
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package mobi.glowworm.lib.utils.debug;

import android.util.Log;

/**
 * A Basic logging class that allows ProGuard to strip out all logging artifacts,
 * including string concatenation which is left in the app when using the default logging SDK.
 * <p/>
 * Works well with the following line inserted into <code>proguard-project.pro</code> file:
 * <ul>
 * <li>-assumenosideeffects class mobi.glowworm.lib.utils.debug.Dbug { public * ; }</li>
 * </ul>
 * <p>
 * Adapted from <a href="https://gist.github.com/mobiRic/9786897">mobiRic/Dbug.java on GitHub Gist</a>
 */
@SuppressWarnings({"WeakerAccess", "unused"})
public class Dbug {

    /**
     * Tag for logcat output.
     */
    public static final String TAG = Dbug.class.getSimpleName();

    /**
     * Convenient debug log method that uses the application's default log tag.
     * <p>
     * Based on techniques by Binu John on his blog post "Varargs and debug print"
     * (no longer available).
     *
     * @param text Array of Objects that create the debug message. This is preferable to
     *             concatenating many strings into a single parameter as that cannot be optimised
     *             away by ProGuard.
     */
    public static void log(Object... text) {
        logWithTag(TAG, text);
    }

    /**
     * Convenient debug log method that allows for custom log tags.
     *
     * @param tag  Custom tag to appear in logcat
     * @param text Array of Objects that create the debug message. This is preferable to
     *             concatenating many strings into a single parameter as that cannot be optimised
     *             away by ProGuard.
     * @see #log(Object...)
     */
    public static void logWithTag(String tag, Object... text) {

        // manually concatenate the various arguments
        StringBuilder sb = new StringBuilder();
        if (text != null) {
            for (Object object : text) {
                if (object != null) {
                    sb.append(object.toString());
                } else {
                    sb.append("<null>");
                }
            }
        }

        Log.d(tag, sb.toString());
    }

}

Android debug logging class, allowing easy optimised removal by ProGuard in production builds. By placing all string concatenation inside the methods rather than passing a single string, ProGuard is able to remove all logging artifacts. Without this, ProGuard would leave the string concatenation code when removing log calls.

Note: currently you have to configure the value of DEBUG_ON manually. This is due to bugs in various SDK implementations of the Build Debug flags.

This manual setting also allows for signed builds to contain full debug output, which has been shown useful in at least one production case.

rev 2:

• fix null pointer

/*

• Copyright (C) 2011 Glowworm Software
  *
• Licensed under the Apache License, Version 2.0 (the "License");
• you may not use this file except in compliance with the License.
• You may obtain a copy of the License at
  *

•  http://www.apache.org/licenses/LICENSE-2.0
  
• Unless required by applicable law or agreed to in writing, software
• distributed under the License is distributed on an "AS IS" BASIS,
• WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
• See the License for the specific language governing permissions and
• limitations under the License.
  */