Android logcat Application Guide

Android is an open-source mobile phone operating system launched by Google based on the Linux platform. It has been launched to reach out to the favorite of the majority of programmers. Here, we will first have an in-depth understanding of the Android logcat application to facilitate our practical application.

Options and descriptions

1. -S: sets the filter by default.
2. -F file output to log file
3. -C clear logs
4. -D. Obtain logs.
5. -G: Get the log size.
6. For the-v format setting log, see the following format print format)

-V format and example

 
 

  
  
brief W/tag ( 876): message   
  
  
process W( 876) message (tag)   
  
  
tag W/tag : message   
  
  
thread W( 876:0x37c) message   
  
  
raw message   
  
  
time 09-08 05:40:26.729 W/tag ( 876): message   
  
  
threadtime 09-08 05:40:26.729 876 892 W tag : message   
  
  
long [ 09-08 05:40:26.729 876:0x37c W/tag ] message  
 
 

Code example:

AndroidManifest. xml: Add read permission

 
 

  
  
< uses-permission android:name=
"android.permission.READ_LOGS" />   
  
  
< uses-permission android:name=
"android.permission.READ_LOGS" /> 
 
 

Clear logs

 
 

  
  
try {   
  
  
Runtime.getRuntime().exec("logcat -c");   
  
  
} catch(Exception e) {   
  
  
try {  
  
  
Runtime.getRuntime().exec("logcat -c");  
  
  
} catch(Exception e) {  
  
  
} 
 
 

Get logs

 
 

  
  
try {   
  
  
ArrayList< String> commandLine = new ArrayList< String>();   
  
  
commandLine.add( "logcat");   
  
  
commandLine.add( "-d");   
  
  
commandLine.add( "-v");   
  
  
commandLine.add( "time");   
  
  
commandLine.add( "-s");   
  
  
commandLine.add( "tag:W");   
  
  
Process process = Runtime.getRuntime().exec
( commandLine.toArray( new String[commandLine.size()]));   
  
  
BufferedReader bufferedReader = new BufferedReader
( new InputStreamReader(process.getInputStream()), 1024);   
  
  
String line = bufferedReader.readLine();   
  
  
while ( line != null) {   
  
  
log.append(line);   
  
  
log.append("\n")   
  
  
}   
  
  
} catch ( IOException e) {   
  
  
}   
  
  
try {  
  
  
ArrayList< String> commandLine = new ArrayList< String>();  
  
  
commandLine.add( "logcat");  
  
  
commandLine.add( "-d");  
  
  
commandLine.add( "-v");  
  
  
commandLine.add( "time");  
  
  
commandLine.add( "-s");  
  
  
commandLine.add( "tag:W");  
  
  
Process process = Runtime.getRuntime().exec
( commandLine.toArray( new String[commandLine.size()]));  
  
  
BufferedReader bufferedReader = new BufferedReader
( new InputStreamReader(process.getInputStream()), 1024);  
  
  
String line = bufferedReader.readLine();  
  
  
while ( line != null) {  
  
  
log.append(line);  
  
  
log.append("\n")  
  
  
}  
  
  
} catch ( IOException e) {  
  
  
} 
 
 

Result:

 
 

  
  
09-08 09:44:42.267 W/tag ( 754): message1   
  
  
09-08 09:44:42.709 W/tag ( 754): message2   
  
  
09-08 09:44:43.187 W/tag ( 754): message3   
  
  
09-08 09:44:45.295 E/tag ( 754): message8