日志是为了方便记录程序的各种异常情况，方便以后对程序的维护的修补，一个程序不可能做到百分百健壮和完美，所以有必要在代码中保存日志，方便维护。Java线程类提供了一个接口UncaughtExceptionHandler，Thread.setDefaultUncaughtExceptionHandler(handler)设置当线程由于未捕获到异常而突然终止，并且没有为该线程定义其他处理程序时所调用的默认处理程序。

   所以我们可以继承UncaughtExceptionHandler， 在handler实现对日志的读写

   public class CrashHandler implements UncaughtExceptionHandler {
	// 系统默认的UncaughtException处理
	private Thread.UncaughtExceptionHandler mDefaultHandler;

	public CrashHandler() {
		mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
	}

	@Override
	public void uncaughtException(Thread thread, Throwable ex) {
		try {
			// 创建日志文件
			File file = createCreashLogFile();

			// 写入日志文件
			if (file != null && file.exists()) {
				writeLog(file, ex);
			}
		} catch (Exception e) {
		    LogUtils.w("", e);
		}

		// 将异常抛给系统处??
		mDefaultHandler.uncaughtException(thread, ex);
	}

	private void writeLog(File logFile, Throwable ex) {
		PrintStream printStream = null;
		FileOutputStream fos = null;

		// 写入日志文件
		try {
			fos = new FileOutputStream(logFile);
			printStream = new PrintStream(fos);
			ex.printStackTrace(printStream);
		} catch (Exception e) {
		    LogUtils.w("", e);
		} finally {
			closeQuietly(printStream);
			closeQuietly(fos);
		}
	}

	private void closeQuietly(OutputStream os) {
		if (os != null) {
			try {
				os.close();
			} catch (IOException e) {
			    LogUtils.w("", e);
			}
		}
	}

	/** 创建??个空白的崩溃日志文件 */
	public static File createCreashLogFile() throws IOException {
		if (!isExternalStorageAvaliable()) { // ??查存储是否可??
			return null;
		}

		File directory = new File(Environment.getExternalStorageDirectory()
				+ "/ViolationQuery/crash_log");
		if (!directory.exists()) {
			directory.mkdirs();
		}
		File file = new File(directory, createCrashLogFileName());
		if (file.exists()) {
			file.delete();
		}
		file.createNewFile();

		return file;
	}

	/** 存储是否可用 */
	public static boolean isExternalStorageAvaliable() {
		String state = Environment.getExternalStorageState();
		if (Environment.MEDIA_MOUNTED.equals(state)) {
			return true;
		} else {
			return false;
		}
	}

	private static String createCrashLogFileName() {
		String dateString = new SimpleDateFormat("yyyyMMdd_HHmmss",
				Locale.getDefault()).format(new Date());
		return "CrashLog_" + dateString + ".txt";
	}
}

<pre name="code" class="java">public class CrashManager {
	public static void start() {
		// 设置异常处理实例
		CrashHandler handler = new CrashHandler();
		Thread.setDefaultUncaughtExceptionHandler(handler);
	}
}

 然后在Application中调用Application中CrashManager.start();这样就大功告成了

android 处理程序crash日志