Here is a quick put-together/drop-in that can be used for capturing all current, or all new (since a last request) log items.
You should modify/extend this, because you might want to return a continuous-stream rather than a LogCapture.
The Android LogCat "Manual": https://developer.android.com/studio/command-line/logcat.html
import android.util.Log;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.Stack;
/**
* Created by triston on 6/30/17.
*/
public class Logger {
// http://www.java2s.com/Tutorial/Java/0040__Data-Type/SimpleDateFormat.htm
private static final String ANDROID_LOG_TIME_FORMAT = "MM-dd kk:mm:ss.SSS";
private static SimpleDateFormat logCatDate = new SimpleDateFormat(ANDROID_LOG_TIME_FORMAT);
public static String lineEnding = "\n";
private final String logKey;
private static List<String> logKeys = new ArrayList<String>();
Logger(String tag) {
logKey = tag;
if (! logKeys.contains(tag)) logKeys.add(logKey);
}
public static class LogCapture {
private String lastLogTime = null;
public final String buffer;
public final List<String> log, keys;
LogCapture(String oLogBuffer, List<String>oLogKeys) {
this.buffer = oLogBuffer;
this.keys = oLogKeys;
this.log = new ArrayList<>();
}
private void close() {
if (isEmpty()) return;
String[] out = log.get(log.size() - 1).split(" ");
lastLogTime = (out[0]+" "+out[1]);
}
private boolean isEmpty() {
return log.size() == 0;
}
public LogCapture getNextCapture() {
LogCapture capture = getLogCat(buffer, lastLogTime, keys);
if (capture == null || capture.isEmpty()) return null;
return capture;
}
public String toString() {
StringBuilder output = new StringBuilder();
for (String data : log) {
output.append(data+lineEnding);
}
return output.toString();
}
}
/**
* Get a list of the known log keys
* @return copy only
*/
public static List<String> getLogKeys() {
return logKeys.subList(0, logKeys.size() - 1);
}
/**
* Platform: Android
* Get the logcat output in time format from a buffer for this set of static logKeys.
* @param oLogBuffer logcat buffer ring
* @return A log capture which can be used to make further captures.
*/
public static LogCapture getLogCat(String oLogBuffer) { return getLogCat(oLogBuffer, null, getLogKeys()); }
/**
* Platform: Android
* Get the logcat output in time format from a buffer for a set of log-keys; since a specified time.
* @param oLogBuffer logcat buffer ring
* @param oLogTime time at which to start capturing log data, or null for all data
* @param oLogKeys logcat tags to capture
* @return A log capture; which can be used to make further captures.
*/
public static LogCapture getLogCat(String oLogBuffer, String oLogTime, List<String> oLogKeys) {
try {
List<String>sCommand = new ArrayList<String>();
sCommand.add("logcat");
sCommand.add("-bmain");
sCommand.add("-vtime");
sCommand.add("-s");
sCommand.add("-d");
sCommand.add("-T"+oLogTime);
for (String item : oLogKeys) sCommand.add(item+":V"); // log level: ALL
sCommand.add("*:S"); // ignore logs which are not selected
Process process = new ProcessBuilder().command(sCommand).start();
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
LogCapture mLogCapture = new LogCapture(oLogBuffer, oLogKeys);
String line = "";
long lLogTime = logCatDate.parse(oLogTime).getTime();
if (lLogTime > 0) {
// Synchronize with "NO YEAR CLOCK" @ unix epoch-year: 1970
Calendar calendar = Calendar.getInstance();
calendar.setTime(new Date(oLogTime));
calendar.set(Calendar.YEAR, 1970);
Date calDate = calendar.getTime();
lLogTime = calDate.getTime();
}
while ((line = bufferedReader.readLine()) != null) {
long when = logCatDate.parse(line).getTime();
if (when > lLogTime) {
mLogCapture.log.add(line);
break; // stop checking for date matching
}
}
// continue collecting
while ((line = bufferedReader.readLine()) != null) mLogCapture.log.add(line);
mLogCapture.close();
return mLogCapture;
} catch (Exception e) {
// since this is a log reader, there is nowhere to go and nothing useful to do
return null;
}
}
/**
* "Error"
* @param e
*/
public void failure(Exception e) {
Log.e(logKey, Log.getStackTraceString(e));
}
/**
* "Error"
* @param message
* @param e
*/
public void failure(String message, Exception e) {
Log.e(logKey, message, e);
}
public void warning(String message) {
Log.w(logKey, message);
}
public void warning(String message, Exception e) {
Log.w(logKey, message, e);
}
/**
* "Information"
* @param message
*/
public void message(String message) {
Log.i(logKey, message);
}
/**
* "Debug"
* @param message a Message
*/
public void examination(String message) {
Log.d(logKey, message);
}
/**
* "Debug"
* @param message a Message
* @param e An failure
*/
public void examination(String message, Exception e) {
Log.d(logKey, message, e);
}
}
In your project which performs activity logging:
Logger log = new Logger("SuperLog");
// perform logging methods
When you want to capture everything you logged through "Logger"
LogCapture capture = Logger.getLogCat("main");
When you get hungry and you want to snack on more logs
LogCapture nextCapture = capture.getNextCapture();
You can get the capture as a string with
String captureString = capture.toString();
Or you can get the log items of the capture with
String logItem = capture.log.get(itemNumber);
There is no exact static method to capture foreign log keys but there is a way none the less
LogCapture foreignCapture = Logger.getLogCat("main", null, foreignCaptureKeyList);
Using the above will also permit you to call Logger.this.nextCapture on the foreign capture.
