🖥️
Log4think
  • Introduction
  • Archive
  • 2016-12-13 JavaScript 中几种不同的基于 prototype 继承方式的区别
  • 2014-09-02 Facebook的Dalvik运行期补丁
  • 2014-08-19 理解AnguarJS中的模板编译
  • 2014-08-13 在Android中使用OSGi框架(Knopflerfish)
  • 2014-08-13 在Android中使用OSGi框架(Apache Felix)
  • 2014-07-30 3rd-party apt-key list for Ubuntu
  • 2014-07-21 'Failed to clone a large git repository: The remote end hung up unexpectedly'
  • 2014-07-02 genymotion Qt error in Ubuntu
  • 2014-04-30 可自动安装依赖的Ubuntu离线包安装工具 gdebi
  • 2014-04-23 解决搜狗输入法Ubuntu 14.04下黑块状态条
  • 2014-04-08 Setup Ghost blog system on Ubuntu
  • 2014-03-28 Trace a process
  • 2014-03-25 Forecast::IO 599 Internal Exception
  • 2014-03-23 Mac Tips
  • 2014-01-17 LD_LIBRARY_PATH shouldn't contain the current directory
  • 2014-01-10 Python on vim
  • 2013-11-12 ibus-pinyin doesn't work in KUbuntu 13.10
  • 2013-11-11 phpMyAdmin login error to remote server
  • 2013-11-04 Get SNMP(v3) working on Ubuntu 12.04
  • 2013-10-30 Accessing Facebook by LWP
  • 2013-10-17 Log4perl多个Appender重复输出日志的问题解决办法
  • 2013-04-19 How to enable ORMLite internal log on Android
  • 2013-02-20 Bash Shortcuts
  • 2013-02-20 '"adb shell dumpsys" parameter list'
  • 2013-01-27 循环有序数组的二分查找
  • 2013-01-23 为Java运行环境导入根证书解决Eclipse的TFS插件的"PKIX path building failed"错误
  • 2013-01-21 ant 中通过重新定义 project.all.jars.path 在 classpath 中引入外部 jar 文件
  • 2012-09-22 Android的滚动条实现细节
  • 2012-02-05 hostname自动变成bogon的问题
  • 2011-07-09 代码段速记 gist.github.com
  • 2011-07-08 A perl Data.Dumper clone for Python
  • 2011-06-22 魔兽世界私服Trinity,从源码开始
  • 2011-06-13 魔兽世界3.3.5 13930登录数据包分析
  • 2011-06-13 魔兽世界 3.3.5 13930 Trinity 认证补丁
  • 2011-05-20 统一业务模型(UBM) in ERP5
  • 2011-03-08 制作ASCII字符动画
  • 2011-01-14 Ubuntu升级导致的udevd错误修复
  • 2011-01-09 行列有序矩阵求第K个数
  • 2011-01-09 字节按位逆序
  • 2011-01-01 编程之美 1.2 中国相帅问题的一个简洁解法
  • 2010-11-26 为Windows 7/Windows Server 2008添加IPX协议
  • 2010-11-12 How to debug with Android Logging
  • 2010-09-16 利用google-code-prettify做网页内源码的语法高亮
  • 2010-09-05 10 Ways We Hurt Our Romantic Relationships
  • 2010-08-30 利用ipkall+xlite+iptel.org开通google voice
  • 2010-08-27 避免Android开发中的ANR
  • 2010-08-27 在Eclipse中查看Android SDK的源代码
  • 2010-08-18 Git中判断一个commit是否在某个branch中
  • 2010-08-04 修正auto-excerpt产生带格式的摘要
  • 2010-03-31 Go 编程语言入门教程
  • 2010-03-13 利用外部VPS主机通过ssh隧道穿透防火墙连接内网
  • 2009-12-30 旋转矩阵
  • 2009-02-10 为什么cpio要比tar好
  • 2008-12-11 ThoughtWorks 的一道笔试题
  • 2008-11-18 长距离打车如何省钱?
  • 2007-02-08 ftp后台自动上传下载
  • 2006-06-12 vi cheatsheet
  • 2006-04-19 修正mysqlcc在MySQL 5.0上常报的 Table 'xxx' doesn't exist 错误
  • 2006-04-01 'Perl中不寻常的 ?: 运算符'
  • 2005-09-13 关于IoC、低耦合、配置文件及其本质意义的思考
  • 2005-09-13 Perl与数据库DBI快速入门
  • 2005-09-12 Perl无废话入门指南
  • 2005-07-16 Solaris 下安装Perl的DBD-mysql模块失败的原因以及解决办法
  • 2004-10-15 SharpDevelop的AddInTree View 插件
  • 2004-10-14 SharpDevelop源码分析 (完整版)
由 GitBook 提供支持
在本页
  • Logging interface For Java applications
  • Logging class Introduction
  • Logging interface For Native applications
  • Log command on Android

这有帮助吗?

2010-11-12 How to debug with Android Logging

![AP Logger Architecture]

The above image shows the architecture of Android logging system.It provides a java class for logging named android.util.Log. It also provides log macros for native C applications in liblog.

There are four log devices in the kernel. Three for user space log: /dev/log/main, /dev/log/radio, /dev/log/events. One for kernel space log: /dev/log/kernel.

For user space applications, those binary log messages will be written to /dev/log/events. Those log messages with the tag "HTC_RIL" "RILJ" "RILC" "RILD" "RIL" "AT" "GSM" "STK" will be written to /dev/log/radio. Other log messages will be written to /dev/log/main.

The log devices named /dev/log/kernel is for kernel log message collection. A console is registered in /dev/log/kernel and collect all the printk output to the device. It will output kernel log messages with the same log format as other log devices.Logcat is a tool provided by Android. It could read log messages from log devices and output to the console or to a file. You can find the detail usage later.

An aplog daemon is added for offline log. A filter is added to do some security checking.

Logging interface For Java applications

Logging class Introduction

Class Name: android.util.Log

General method:

 Log.v()
 Log.d()
 Log.i()
 Log.w()

The order in terms of verbosity, from least to most is ERROR, WARN, INFO, DEBUG, VERBOSE. VERBOSE should never be compiled into an application except during development. DEBUG logs are compiled in but stripped at runtime. ERROR, WARN and INFO logs are always kept.

TIP: A good convention is to declare a TAG constant in your class: private static final String TAG = "TAG_MyActivity";>and use that in subsequent calls to the log methods. Log.v(TAG, "index=" + i);When you're building the string to pass into Log.d, Java uses a StringBuilder and at least three allocations occur: the StringBuilder itself, the buffer, and the String object. Realistically, there is also another buffer allocation and copy, and even more pressure on the GC. That means that if your log message is filtered out, you might be doing significant work and incurring significant overhead.

Program Example

package com.android.hello;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.util.Log; /*import log class*/

private static final String TAG = "MyActivity"; /* define log tag*/

public class !HelloAndroid extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreaipte(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        TextView tv = new TextView(this);
        tv.setText("Hello, Android");
        setContentView(tv);

        Log.i(TAG, "this is a log.i message");
        Log.v(TAG, "test is a log.v message");
        Log.d(TAG, "test is a log.d message");
        Log.w(TAG, "test is a log.w message");
        Log.e(TAG, "test is a log.e message");
    }
}

Logging interface For Native applications

Header File include <cutils/log.h>###Logging Macros

Common Logging Macros

LOGV LOGD LOGI LOGW LOGE

Condition Logging Macros

LOGV_IF LOGD_IF LOGI_IF LOGW_IF LOGE_IF

The definition is as below:

#define CONDITION(cond) (__builtin_expect((cond)!=0,0))
#define LOGV_IF(cond, ...)   ( (CONDITION(cond)) ?((void)LOG(LOG_VERBOSE, LOG_TAG, VA_ARGS)) : (void)0 )

Logging Macros overview

API for sending log output.

NOTE:

  1. You should define LOG_TAG in your C source code firstly.

  2. To build out C/C++ applications outside android, you should add LOCAL_SHARED_LIBRARIES := liblog libcutils in your Android.mk file

Program Example

#include <stdio.h>
#include <cutils/log.h> /* log header file*/
#include <cutils/properties.h>

/* define log tag */
#ifdef LOG_TAG
#undef LOG_TAG
#define LOG_TAG "app"
#endif
int main()
{
    LOGV("Verbose: _app");
    LOGD("Debug: _app");
    LOGI("Info: _app");
    LOGW("Warn: _app");
    LOGE("Error: _app");
    printf("Hello Android.\n");
    return 0;
}

Log command on Android

Command location

/system/bin/log

Command usage

log [-p priorityChar] [-t tag] message

priorityChar should be one of : v, d, i, w, e## Log format on Android The format of a log messages is

tv_sec     tv_nsec     priority      pid     tid      tag      messageLen       Message
  • tag: log tag

  • tv_sec & tv_nsec: the timestamp of the log messages

  • pid: the process id of where log messages come from

  • tid: the thread id

  • Priority value is one of the following character values, ordered from lowest to highest priority:

    • V - Verbose (lowest priority)*

    • D - Debug*

    • I - Info*

    • W - Warning*

    • E - Error*

    • F - Fatal*

    • S - Silent (highest priority, on which nothing is ever printed)*

上一页2010-11-26 为Windows 7/Windows Server 2008添加IPX协议下一页2010-09-16 利用google-code-prettify做网页内源码的语法高亮

最后更新于5年前

这有帮助吗?

For more details, please visit

Android log reference