android捕获异常并保存到sd卡文件目录里

/**
 * UncaughtException处理类,当程序发生Uncaught异常的时候,有该类来接管程序,并记录发送错误报告.
 * 
 * @author user
 */
public class CrashHandler implements UncaughtExceptionHandler
{
    /** tag */
    public static final String TAG = "CrashHandler";

    // CrashHandler实例
    private static CrashHandler instance = new CrashHandler();

    private final int sleepDuration = 3000;

    // 系统默认的UncaughtException处理类
    private Thread.UncaughtExceptionHandler mDefaultHandler;

    // 程序的Context对象
    private Context mContext;

    // 用来存储设备信息和异常信息
    private Map<String, String> infos = new HashMap<String, String>();

    // 用于格式化日期,作为日志文件名的一部分
    private DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");

    /** 保证只有一个CrashHandler实例 */
    private CrashHandler()
    {
    }

    /**
     * 获取CrashHandler实例 ,单例模式
     *
     * @return CrashHandler实例
     */
    public static CrashHandler getInstance()
    {
        return instance;
    }

    /**
     * 初始化
     * 
     * @param context
     *            上下文
     */
    public void init(Context context)
    {
        mContext = context;
        // 获取系统默认的UncaughtException处理器
        mDefaultHandler = Thread.getDefaultUncaughtExceptionHandler();
        // 设置该CrashHandler为程序的默认处理器
        Thread.setDefaultUncaughtExceptionHandler(this);
    }

    /**
     * 当UncaughtException发生时会转入该函数来处理
     */
    @Override
    public void uncaughtException(Thread thread, Throwable ex)
    {
        LogUtil.w(TAG, "uncaughtException");
        if (!handleException(ex) && mDefaultHandler != null)
        {
            // 如果用户没有处理则让系统默认的异常处理器来处理
            mDefaultHandler.uncaughtException(thread, ex);
        }
        else
        {
            try
            {
                Thread.sleep(sleepDuration);
            }
            catch (InterruptedException e)
            {
                LogUtil.e(TAG, "error : ", e);
            }
            // 退出程序
            android.os.Process.killProcess(android.os.Process.myPid());
            System.exit(1);
        }
    }

    /**
     * 自定义错误处理,收集错误信息 发送错误报告等操作均在此完成.
     * 
     * @param ex 错误信息
     * @return true:如果处理了该异常信息;否则返回false.
     */
    private boolean handleException(Throwable ex)
    {
        LogUtil.w(TAG, "handleException");
        if (ex == null)
        {
            return false;
        }
        ex.printStackTrace();
        // 使用Toast来显示异常信息
        new Thread()
        {
            @Override
            public void run()
            {
                Looper.prepare();
                Toast.makeText(mContext, "很抱歉,程序出现异常,即将退出.", Toast.LENGTH_LONG)
                        .show();
                Looper.loop();
            }
        }.start();
        // 收集设备参数信息
        collectDeviceInfo(mContext);
        // 保存日志文件
        saveCrashInfoToFile(ex);
        return true;
    }

    /**
     * 收集设备参数信息
     * 
     * @param ctx
     *            上下文
     */
    public void collectDeviceInfo(Context ctx)
    {
        LogUtil.w(TAG, "collectDeviceInfo");
        try
        {
            PackageManager pm = ctx.getPackageManager();
            PackageInfo pi = pm.getPackageInfo(ctx.getPackageName(),
                    PackageManager.GET_ACTIVITIES);
            if (pi != null)
            {
                String versionName = pi.versionName == null ? "null"
                        : pi.versionName;
                String versionCode = pi.versionCode + "";
                infos.put("versionName", versionName);
                infos.put("versionCode", versionCode);
            }
        }
        catch (NameNotFoundException e)
        {
            LogUtil.e(TAG, "an error occured when collect package info", e);
        }
        Field[] fields = Build.class.getDeclaredFields();
        for (Field field : fields)
        {
            try
            {
                field.setAccessible(true);
                infos.put(field.getName(), field.get(null).toString());
                LogUtil.d(TAG, field.getName() + " : " + field.get(null));
            }
            catch (Exception e)
            {
                LogUtil.e(TAG, "an error occured when collect crash info", e);
            }
        }
    }

    /**
     * 保存错误信息到文件中
     * 
     * @param ex
     * @return 返回文件名称,便于将文件传送到服务器
     */
    private String saveCrashInfoToFile(Throwable ex)
    {
        LogUtil.w(TAG, "saveCrashInfo2File");
        StringBuffer sb = new StringBuffer();
        for (Map.Entry<String, String> entry : infos.entrySet())
        {
            String key = entry.getKey();
            String value = entry.getValue();
            sb.append(key + "=" + value + "\n");
        }

        Writer writer = new StringWriter();
        PrintWriter printWriter = new PrintWriter(writer);
        ex.printStackTrace(printWriter);
        Throwable cause = ex.getCause();
        while (cause != null)
        {
            cause.printStackTrace(printWriter);
            cause = cause.getCause();
        }
        printWriter.close();
        String result = writer.toString();
        sb.append(result);
        try
        {
            long timestamp = System.currentTimeMillis();
            String time = formatter.format(new Date());
            String fileName = "crash-" + time + "-" + timestamp + ".log";
            if (Environment.getExternalStorageState().equals(
                    Environment.MEDIA_MOUNTED))
            {
                String path = "保存路径";
                File dir = new File(path);
                if (!dir.exists())
                {
                    dir.mkdirs();
                }
                FileOutputStream fos = new FileOutputStream(path + fileName);
                fos.write(sb.toString().getBytes());
                fos.close();
            }
            return fileName;
        }
        catch (Exception e)
        {
            LogUtil.e(TAG, "an error occured while writing file...", e);
        }
        return null;
    }
}