LogcatHelper.java

package com.tencent.wstt.gt.log.logcat;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class LogcatHelper {

	public static final String BUFFER_MAIN = "main";
	public static final String BUFFER_EVENTS = "events";
	public static final String BUFFER_RADIO = "radio";

	public static Process getLogcatProcess(String buffer) throws IOException {

		List<String> args = getLogcatArgs(buffer);
		Process process = RuntimeHelper.exec(args);

		return process;
	}

	private static List<String> getLogcatArgs(String buffer) {
		List<String> args = new ArrayList<String>(Arrays.asList("logcat", "-v", "time"));

		// for some reason, adding -b main excludes log output from
		// AndroidRuntime runtime exceptions,
		// whereas just leaving it blank keeps them in. So do not specify the
		// buffer if it is "main"
		if (!buffer.equals(BUFFER_MAIN)) {
			args.add("-b");
			args.add(buffer);
		}

		return args;
	}

	public static String getLastLogLine(String buffer) {
		Process dumpLogcatProcess = null;
		BufferedReader reader = null;
		String result = null;
		try {

			List<String> args = getLogcatArgs(buffer);
			args.add("-d"); // -d just dumps the whole thing

			dumpLogcatProcess = RuntimeHelper.exec(args);
			reader = new BufferedReader(new InputStreamReader(dumpLogcatProcess.getInputStream()), 8192);

			String line;
			while ((line = reader.readLine()) != null) {
				result = line;
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (dumpLogcatProcess != null) {
				RuntimeHelper.destroy(dumpLogcatProcess);
			}
			// post-jellybean, we just kill the process, so there's no need
			// to close the bufferedReader. Anyway, it just hangs.
			if (VersionHelper.getVersionSdkIntCompat() < VersionHelper.VERSION_JELLYBEAN && reader != null) {
				try {
					reader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}

		return result;
	}
}