Android's logging information is accessed through logcat, usually usingadbThe command is as follows:
adb logcat [-option] [filter]
or
adb shell Enter the shell interface and enter: logcat [-option] [filter]
Information output method:
The default input logcat prints the default information, and its output is roughly as follows:
I/Applog(20054) : An Informational Log message .
illustrate:
1. Logs are recorded in brief mode by default.
2. I means that the message type is information.
3. Applog is the filtering flag, and 20054 represents the thread ID.
4. The colon is followed by the message body.
There is another commonly used method with date and time. You need to use -v to switch. Generally, the command is entered as follows: logcat -v time, and the output is as follows:
08-04 22:52:33 .565 I/Applog(20054) : An Informational Log message .
Note: There are more time and date items than the above information.
Filter log information
The filter of logcat is divided into two parts, one is tag name and the other is log level. Just follow the following format and just follow the logcat.
< tag name > : < Lowest log level to print >
General format: logcat Applog:I can filter out the above logs.
Key points:
1. When printing logs, you can use the * wildcard character to indicate that all contents are in line with each other. Before the colon, all tags are marked, and after the colon, all levels are printed. By default, no deletion is done, that is, the default is *.
2. The log level order from high to low is: no disturbance (Silent, S), fatal error (Fatal, F), error (Error, E), warning (Warning, W), information (Info, I), debug (Debug, D), and redundancy (Verbose, V).
3. Two filters can be used to work simultaneously, and the relationship is logical, that is, information that meets 2 conditions at the same time will be output.
For example: logcat -v time Applog:V *:S can generate information that only contains Applog tags.
Clear log
Use -c to clear the current information and prevent interference with the current printing. The format is as follows:
logcat -c
Save logs
Logs can be saved to Android devices or locally, and are carried out as follows:
Save locally: adb logcat -v time Applog:V *:S >>
Save to Android device: logcat -v time -f /sdcard/ Applog:V *:S
Access to secondary logs
Android also has several different logs, which are the main logs by default. To view other logs, you can use -b to view them. The following are 2 commonly used examples:
logcat -b event # Access event log.
logcat -b radio # Access the radio log.