这是一个从XUtils3中摘抄出来的打印日志工具类。这个类打印日志比较详细，可以打印类名、方法名。
isDebug为打印日志开关，初始化的时候可以使用LogUtils.isDebug(boolean b)来控制开关状态。

public class LogUtils { public static String customTagPrefix = "x_log"; private static boolean isDebug = true; private LogUtils() { } public static void isDebug(boolean b) { isDebug = b; } private static String generateTag() { StackTraceElement caller = new Throwable().getStackTrace()[2]; String tag = "%s.%s(L:%d)"; String callerClazzName = caller.getClassName(); callerClazzName = callerClazzName.substring(callerClazzName.lastIndexOf(".") + 1); tag = String.format(tag, callerClazzName, caller.getMethodName(), caller.getLineNumber()); tag = TextUtils.isEmpty(customTagPrefix) ? tag : customTagPrefix + ":" + tag; return tag; } public static void d(String content) { if (!isDebug) return; String tag = generateTag(); Log.d(tag, content); } public static void d(String content, Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.d(tag, content, tr); } public static void e(String content) { if (!isDebug) return; String tag = generateTag(); Log.e(tag, content); } public static void e(String content, Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.e(tag, content, tr); } public static void i(String content) { if (!isDebug) return; String tag = generateTag(); Log.i(tag, content); } public static void i(String content, Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.i(tag, content, tr); } public static void v(String content) { if (!isDebug) return; String tag = generateTag(); Log.v(tag, content); } public static void v(String content, Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.v(tag, content, tr); } public static void w(String content) { if (!isDebug) return; String tag = generateTag(); Log.w(tag, content); } public static void w(String content, Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.w(tag, content, tr); } public static void w(Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.w(tag, tr); } public static void wtf(String content) { if (!isDebug) return; String tag = generateTag(); Log.wtf(tag, content); } public static void wtf(String content, Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.wtf(tag, content, tr); } public static void wtf(Throwable tr) { if (!isDebug) return; String tag = generateTag(); Log.wtf(tag, tr); }}