android开发之自定义log工具

前言

原理剖析

public final class BuildConfig {
    public final static boolean DEBUG = true;
}

Logger

public class Logger {

    public Logger() { }

    public void v(String format, Object... args)  { }

    public void d(String format, Object... args)  { }

    public void i(String format, Object... args)  { }

    public void w(String format, Object... args)  { }

    public void w(Throwable tr, String format, Object... args)  { }

    public void e(String format, Object... args)  { }

    public void e(Throwable tr, String format, Object... args)  { }

    public void wtf(String format, Object... args)  { }

    public void wtf(Throwable tr, String format, Object... args)  { }
}

LogManager

public class LogManager {
    public static final String Default_Tag = "TAGINFO";

    private static Logger Logger;
    private static HashMap<String,Logger> LoggerMap = null;

    public static Logger getLogger() {
        return getLogger(null);
    }

    public static Logger getLogger(String tag) {
        if(BuildConfig.DEBUG) {
            return getDebugLogger(tag);         
        } else {
            if (Logger == null) {
                Logger = new Logger();
            }
            return Logger;
        }
    }

    private static Logger getDebugLogger(String tag) {
        if(null == tag) tag = Default_Tag;

        Logger logger;
        if(null == LoggerMap) {
            synchronized (LogManager.class) {
                if(null == LoggerMap) LoggerMap = new HashMap<String,Logger>(); 
            }
        }

        if (LoggerMap.containsKey(tag))
            logger = LoggerMap.get(tag);
        else {
            logger = new DebugLogger(tag);
            LoggerMap.put(tag, logger);
        }
        return logger;
    }

    private static class DebugLogger extends Logger {
        private String tag;

        private DebugLogger(String tag) {    

            if(null != this.tag && tag == this.tag) return;     
            this.tag = null == tag? LogManager.Default_Tag:tag;
        }

        @Override
        public void v(String format, Object... args) {
            Log.v(tag, buildSimpleMessage(format, args));
        }

        @Override
        public void d(String format, Object... args) {
            Log.d(tag, buildSimpleMessage(format, args));
        }

        @Override
        public void i(String format, Object... args) {
            Log.i(tag, buildSimpleMessage(format, args));
        }

        @Override
        public void w(String format, Object... args) {
            Log.w(tag, buildMessage(format, args));
        }

        @Override
        public void w(Throwable tr, String format, Object... args) {
            Log.w(tag, buildMessage(format, args), tr);
        }

        @Override
        public void e(String format, Object... args) {
            Log.e(tag, buildMessage(format, args));
        }

        @Override
        public void e(Throwable tr, String format, Object... args) {
            Log.e(tag, buildMessage(format, args), tr);
        }

        @Override
        public void wtf(String format, Object... args) {
            Log.wtf(tag, buildMessage(format, args));
        }

        @Override
        public void wtf(Throwable tr, String format, Object... args) {
            Log.wtf(tag, buildMessage(format, args), tr);
        }

        private String buildSimpleMessage(String format, Object... args) {
            return (args == null) ? format : String.format(Locale.US, format, args);
        }
        private String buildMessage(String format, Object... args) {
            String msg = buildSimpleMessage(format, args);
            StackTraceElement[] trace = new Throwable().fillInStackTrace().getStackTrace();

            String caller = "<unknown>";
            for (int i = 2; i < trace.length; i++) {
                Class<?> clazz = trace[i].getClass();
                if (!clazz.equals(DebugLogger.class)) {
                    String callingClass = trace[i].getClassName();
                    callingClass = callingClass.substring(callingClass.lastIndexOf('.') + 1);
                    callingClass = callingClass.substring(callingClass.lastIndexOf('$') + 1);

                    caller = callingClass + "." + trace[i].getMethodName();
                    break;
                }
            }
            return String.format(Locale.US, "[%d] %s: %s",
                    Thread.currentThread().getId(), caller, msg);
        }
    }
}

使用

LogManager.getLogger().d("keyvalues: %s, keyvalues: %s",values, values);

上述中, %s 设置以字符串格式输出，keyvalues自定数据串标识，values表示和keyvalues对应的实体数据

总结

log日志如何使用直接决定了项目开发的效率，这个和注释是一个样子的。虽然很基础的东西，但是往往都是在项目开发过程中最重要的东西。以网络请求为例，请求的接口地址，参数，返回数据，等一系列数据，通过log输出后，不需要进行UI验证，直接通过数据就验证了业务的精准性。在logcat中，以自定义的TAG为自定义过滤的TAG，直接将数据输出出来，方便开发，方便维护。并且通过这种方式，在测试阶段日志正常输出，但是一旦签名之后，即便设备root之后，通过shell采集数据，这个也一样不会输出。

忠告

敬告各位同行，研发无小事，慎重对待每一个细节。