file.createNewFile() show the exception?

Question

In my project,I need gather the crash messages.The following is my demo,the code goes to file.createNewFile() it will throw the exception,said that not such file or directory,please help me. I don't know why this is.

public class MainActivity extends AppCompatActivity {
    private Button mButton;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mButton = (Button)findViewById(R.id.button);
        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                throw new RuntimeException("Myself throw a exception……");
            }
        });
    }
}

public class MyApplication extends Application {
    private static MyApplication sMyApplication;
    @Override
    public void onCreate() {
        super.onCreate();
        // 在这里为应用设置异常处理，然后程序才能获取未处理的异常
        CrashHandler crashHandler = CrashHandler.getInstance();
        crashHandler.init(this);
    }
    public static MyApplication getInstance(){
        return sMyApplication;
    }
}

    public class CrashHandler implements Thread.UncaughtExceptionHandler {

    private static final String TAG = "CrashHandler";
    private static final boolean DEBUG = true;

    private static final String PATH = Environment.getExternalStorageDirectory().getPath() + "/CrashTest/log/";
    private static final String FILE_NAME = "crash";
    private static final String FILE_NAME_SUFFIX = ".trace";

    private static CrashHandler sCrashHandler = new CrashHandler();
    private Thread.UncaughtExceptionHandler mDefaultCrashHandler;
    private Context mContext;


    private CrashHandler(){}

    // 单例模式
    public static CrashHandler getInstance(){
        return sCrashHandler;
    }

    public void init(Context context){
        mDefaultCrashHandler = Thread.getDefaultUncaughtExceptionHandler();
        Thread.setDefaultUncaughtExceptionHandler(this);
        mContext = context.getApplicationContext();
    }

    /**
     * 这是最关键的函数，当程序中有未捕获的异常，系统将会自动调用此方法
     * @param thread  为出现未捕获异常的线程
     * @param exception 未捕获的异常，有了此异常，我们就能得到异常信息
     */
    @Override
    public void uncaughtException(Thread thread, Throwable exception) {
        try {
            //save exception message to sdcard
            saveExceptionToSDCard(exception);
            //upload exception message to web server
            uploadExceptionToServer(exception);
        } catch (IOException e) {
            e.printStackTrace();
        }

        // 如果系统提供了默认的异常处理器，就交给系统自己处理，否则就自己结束掉自己
        if (mDefaultCrashHandler!=null){
            mDefaultCrashHandler.uncaughtException(thread,exception);
        }else {
            Process.killProcess(Process.myPid());
        }
    }


    // 将异常信息保存到SDCard
    private void saveExceptionToSDCard(Throwable ex) throws IOException {
        // 如果SD卡不存在或无法使用，则无法写入异常信息，给与提示
        if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
            if (DEBUG){
                Log.w(TAG,"sdcard unmounted , skip save exception"); //sd卡未安装好，跳出存储异常
            }
            return;
        }
        // 文件存储路径
        File dir = new File(PATH);
        if (!dir.exists()){
            dir.mkdir();
        }
        // 获取当前时间
        long current = System.currentTimeMillis();
        String time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(current));
        // 创建存储异常信息的文件
        File file = new File(dir.getAbsolutePath()+"/"+FILE_NAME+time+FILE_NAME_SUFFIX);
        if (!file.exists()){
            try {
                file.createNewFile();     //I debug when code goes to here will throw exception
            }catch (Exception e){
                e.printStackTrace();
            }

        }

        try {
            PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(file)));
            pw.print(time);
            savePhoneInfo(pw);
            pw.println();
            ex.printStackTrace(pw);   //输出异常信息
            pw.close();
        }catch (PackageManager.NameNotFoundException e){
            Log.e(TAG,"save crash info failed");
        }

    }

    // 保存手机的信息
    private void savePhoneInfo(PrintWriter pw) throws PackageManager.NameNotFoundException {
        PackageManager pm = mContext.getPackageManager();
        PackageInfo pi = pm.getPackageInfo(mContext.getPackageName(),PackageManager.GET_ACTIVITIES);

        // APP的版本信息
        pw.print("APP Version:");
        pw.print(pi.versionName);
        pw.print('_');
        pw.print(pi.versionCode);

        // Android 手机版本号
        pw.print("OS Version:");
        pw.print(Build.VERSION.RELEASE);
        pw.print('_');
        pw.print(Build.VERSION.SDK_INT);

        // 手机制造商
        pw.print("Vendor:");
        pw.print(Build.MANUFACTURER);

        // 手机型号
        pw.print("Model:");
        pw.print(Build.MODEL);

        // CPU架构
        pw.print("CUP ABI:");
        pw.print(Build.CPU_ABI);
    }

    // 将异常信息上传到服务器
    private void uploadExceptionToServer(Throwable ex){

    }
}

Answer 1

in saveExceptionToSDCard() change dir.mkdir() to dir.mkdirs()