adb logcat教程
1.速查
$adb logcat -g //打印和缓冲区使用情况
$adb logcat -c main //清除main缓存区
$adb logcat -v threadtime -f /data/camera.log | grep -Ei "camera | daemon"
- -v threadtime 输出格式 ,默认是 brief
- -f /data/camera.log 保存到文件
- grep -Ei "camera | daemon" 是过滤,-i是忽略大小写,E是指定多个过滤字符串，logcat的自代过滤器（tag:优先级）不好用！
2.先要知道的第一件事
android把log输出到不同的缓冲区中，常见的几个log缓冲区：
| 缓冲区 | 描述 |
| radio | 输出通信系统的log |
| system | 输出系统组件的log |
| crash | 崩溃日志 |
| events | 输出event模块的log |
| main |
所有java层的log，以及不属于上面3层的log |
| all |
全部 |
3.先要知道的第二件事
- 有两个logcat ： adb logcat 与 adb shell logcat 命令不同，使用场景不同。
- logcat有很多参数：adb logcat --help 可查看。
4.参数详解
第１个参数：打印各日志缓冲区的大小并退出
$adb logcag -g
结果如下：
main: ring buffer is 256Kb (235Kb consumed), max entry is 5120b, max payload is 4076b system: ring buffer is 256Kb (238Kb consumed), max entry is 5120b, max payload is 4076b crash: ring buffer is 256Kb (242Kb consumed), max entry is 5120b, max payload is 4076b
第２个参数：打印某个缓冲区日志
$adb logcat -b system
默认是 -b main -b system -b crash.
第３个参数：设置log的输出格式
$adb logcat -v threadtime
threadtime是输出格式，常见输出格式：
|
格式 |
说明 |
| brief | 显示优先级/标记和过程的PID发出的消息（默认格式） |
| process | 只显示PID |
| tag | 只显示优先级/标记 |
| raw | 显示原始的日志消息，没有其他元数据字段 |
| time | 调用显示日期、时间、优先级/标签和过程的PID发出消息 |
| thread | 过滤线程 |
| threadtime | 调用显示日期、时间、优先级、标签以及PID TID线程发出的消息 |
| long | 显示所有元数据字段与空白行和单独的消息 |
第４个参数：设置过滤器[ tag名:优先级 ] ，默认是[*:I]
$adb logcat ActivityManager:I YourApp:D *:S
这个命令指定了３个过滤器：
- ActivityManager:I
- YourApp:D
- *:S
其中ActivityManager和YourApp是tag，Ｉ 、Ｄ 、S是优先级。优先级表如下：从低到高
| V | Verbose(最低优先级) |
| D | Debug |
| I | Info |
| W | Warning |
| E | Error |
| F | Fatal |
| S | Silent |
再来一个例子：
$adb logcat *:E
第５个参数：输出到文件（注意文件保存在设备上）
$adb logcat -v threadtime -f /data/camera.log
5.详解，有些参数可以合并一起，最好分开，如 -v xxx -f xxx
Usage: logcat [options] [filterspecs] options include: -s Set default filter to silent. Like specifying filterspec '*:s' -f <filename> Log to file. Default to stdout -r [<kbytes>] Rotate log every kbytes. (16 if unspecified). Requires -f -n <count> Sets max number of rotated logs to <count>, default 4 -v <format> Sets the log print format, where <format> is one of: brief process tag thread raw time threadtime long -c clear (flush) the entire log and exit -d dump the log and then exit (don't block) -t <count> print only the most recent <count> lines (implies -d) -t '<time>' print most recent lines since specified time (implies -d) -T <count> print only the most recent <count> lines (does not imply -d) -T '<time>' print most recent lines since specified time (not imply -d) count is pure numerical, time is 'MM-DD hh:mm:ss.mmm' -g get the size of the log's ring buffer and exit -b <buffer> Request alternate ring buffer, 'main', 'system', 'radio', 'events', 'crash' or 'all'. Multiple -b parameters are allowed and results are interleaved. The default is -b main -b system -b crash. -B output the log in binary. -S output statistics. -G <size> set size of log ring buffer, may suffix with K or M. -p print prune white and ~black list. Service is specified as UID, UID/PID or /PID. Weighed for quicker pruning if prefix with ~, otherwise weighed for longevity if unadorned. All other pruning activity is oldest first. Special case ~! represents an automatic quicker pruning for the noisiest UID as determined by the current statistics. -P '<list> ...' set prune white and ~black list, using same format as printed above. Must be quoted. filterspecs are a series of <tag>[:priority] where <tag> is a log component tag (or * for all) and priority is: V Verbose D Debug I Info W Warn E Error F Fatal S Silent (supress all output) '*' means '*:d' and <tag> by itself means <tag>:v If not specified on the commandline, filterspec is set from ANDROID_LOG_TAGS. If no filterspec is found, filter defaults to '*:I' If not specified with -v, format is set from ANDROID_PRINTF_LOG or defaults to "brief"
