public class CrashHandler implements Thread.UncaughtExceptionHandler {
    private static final String PATH = Environment.getExternalStorageDirectory().getPath()+"/CrashTest/log";
    private static final String FILE_NAME="Crash";
    private static final String FILE_NAME_SUFFIX=".txt";
    private static CrashHandler crashHandler=new CrashHandler();
    private Thread.UncaughtExceptionHandler mDefaultHandler;
    private static final boolean DEBUG=true;
    private Context mContext;
    private CrashHandler()
    {
    }
    public static CrashHandler getInstance()
    {
        return crashHandler;
    }
    public void init(Context context)
    {
        mDefaultHandler=Thread.getDefaultUncaughtExceptionHandler();
        Thread.setDefaultUncaughtExceptionHandler(this);
        mContext=context;
    }
//最重要的重写的方法在这里处理错误
    @Override
    public void uncaughtException(Thread t, Throwable e) {
        try {
            dumpExceptionToSDcard(e);
        } catch (PackageManager.NameNotFoundException e1) {
            e1.printStackTrace();
        }
        uploadExceptionToserver();
        e.printStackTrace();
        if(mDefaultHandler!=null)
        {
            mDefaultHandler.uncaughtException(t,e);
        }else
        {
            Process.killProcess(Process.myPid());
        }
    }
    private void dumpExceptionToSDcard(Throwable e) throws PackageManager.NameNotFoundException {
        if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            if (DEBUG)
            {
                Log.w("CrashHandrler", "dumpExceptionToSDcard: SDcard unmounted,skip dump exception");
                return;
            }
        }
        File dir=new File(PATH);
        if(!dir.exists())
            dir.mkdirs();
        long current=System.currentTimeMillis();
        String time=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(current));
        File file=new File(PATH+FILE_NAME+FILE_NAME_SUFFIX);
        try {
            PrintWriter writer=new PrintWriter(new BufferedWriter(new FileWriter(file)));
            writer.print(time);
            dumpPhoneInfo(writer);
            writer.println();
            e.printStackTrace(writer);
            writer.close();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }
    private void dumpPhoneInfo(PrintWriter writer) throws PackageManager.NameNotFoundException{
        PackageManager manager=mContext.getPackageManager();
        PackageInfo info=manager.getPackageInfo(mContext.getPackageName(),PackageManager.GET_ACTIVITIES);
        writer.print("APP Version");
        writer.print(info.versionName);
        writer.print("_");
        writer.print(info.versionCode);
        writer.print("OS Version:");
        writer.print(Build.VERSION.RELEASE);
        writer.print("_");
        writer.print(Build.VERSION.SDK_INT);
        writer.print("Vendor:");//手机制造商
        writer.print(Build.MANUFACTURER);
        writer.print("Model: ");//手机型号
        writer.print(Build.MODEL);
        writer.print("CUP ABi");//CPU型号
        writer.print(Build.CPU_ABI);
    }
    private void uploadExceptionToserver() {
    }
}

• 然后在MyApplication里面的OnCreate
  CrashHandler crashHandler=CrashHandler.getInstance();
  crashHandler.init(this);
• 还有加上读写的权限