Question

我正在开发一个JavaFX应用程序。它处于最基本的阶段。但我一直遇到一个奇怪的错误，我无法解决。我已经在线查看，并遵循了建议。但是，问题是如此基本，我无法理解可能是什么问题。它一直告诉我该位置是必需的，即使位置正确并且已指定。

Caused by: java.lang.NullPointerException: Location is required.

它指向Parent root....行。

以下是我用来加载fxml文档的代码：

public static void main(String[] args) {
    launch(args);
}

public void start(Stage primaryStage) throws Exception{
  Parent root = FXMLLoader.load(getClass().getResource("ScheduleView.fxml"));
  primaryStage.setScene(new Scene(root, 500, 500));
  primaryStage.setTitle("Scheduler");
  primaryStage.show();
}

请注意，上面的代码位于计划驱动程序类中。

下面是文件struture

我尝试使用完全相同的FX代码/文档创建一个单独的JavaFX项目，并且它可以工作。任何帮助将不胜感激。

感谢。

Answer 1

将您的fxml文件放入 src / main / resources 目录。

加载它（添加斜杠）：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*Recursive Merge Sort to sort linked list of students in increasing order 
of their age*/
/*A structure dateofbirth is created to store date of birth of each 
student*/
struct dateofbirth {
    int date;
    int month;
    int year;
};

/*Another structure student is created whihc contains information about a 
student and it is also a nested structure that contains another structure 
dateofbirth*/
struct student {
    char firstname[64];
    struct dateofbirth d;
    int height;
    float weight;
    struct student *next;
};

/*Some pointers are made global as they will be used many a times in the 
programs*/
struct student *temp = NULL, *start = NULL, *end = NULL;

/*comparedob will take two dateofbirth structures and compare them which one 
is greater */
int comparison(struct dateofbirth d1,struct dateofbirth d2) {
    if (d1.year > d2.year)
        return 1;
    else if (d1.year < d2.year)
        return -1;
    else if (d1.month > d2.month)
        return 1;
    else if (d1.month < d2.month)
        return -1;
    else if (d1.date > d2.date)
        return 1;
    else if (d1.date < d2.date)
        return -1;
    else return 0;
}

/*It displays the linked list starting from the first till the last*/
void display() {
    temp = start;
    while (temp != NULL) {
        printf("%s, ", temp->firstname);
        if (temp->d.month < 10)
            printf("%d0%d%d,    ", temp->d.date, temp->d.month, temp->d.year);
        else
            printf("%d%d%d, ", temp->d.date, temp->d.month, temp->d.year);
        printf("%d, ", temp->height);
        printf("%.2f\n", temp->weight);
        temp = temp->next;
    }
}

/*It reads from the file*/
void readdata() {
    int a;

    if (start == NULL) { /*This case will be implemented when the first record is read 
from the file*/
        temp = (struct student*) malloc(sizeof(struct student));
        if (temp == NULL) {
            printf("\nNot enough memory");
        }
        scanf("%s", (*temp).firstname);
        scanf("%d", &a);
        (*temp).d.date =   a / 1000000;
        (*temp).d.month = (a % 1000000) / 10000;
        (*temp).d.year =   a % 10000;
        scanf("%d",  &(*temp).height);
        scanf("%lf", &(*temp).weight);
        temp->next = NULL;
        start = temp;
        end = temp;
    } else { /*For all subsequent records this case will be implemented*/
        temp = (struct student*) malloc(sizeof(struct student));
        if (temp == NULL) {
            printf("\nNot enough memory");
        }
        scanf("%s", (*temp).firstname);
        scanf("%d", &a);
        (*temp).d.date =   a / 1000000;
        (*temp).d.month = (a % 1000000) / 10000;
        (*temp).d.year =   a % 10000;
        scanf("%d",  &(*temp).height);
        scanf("%lf", &(*temp).weight);
        temp->next = NULL;
        end->next = temp;
        end = temp;
    }
}

/*This function will swap two student record with the help of pointers*/
void swap(struct student* s1,struct student* s2) {
    struct student s;

    strcpy(s.firstname, (*s1).firstname);
    strcpy((*s1).firstname, (*s2).firstname);
    strcpy((*s2).firstname, s.firstname);
    s.d.date = (*s1).d.date;
    (*s1).d.date = (*s2).d.date;
    (*s2).d.date = s.d.date;
    s.d.month = (*s1).d.month;
    (*s1).d.month = (*s2).d.month;
    (*s2).d.month = s.d.month;
    s.d.year = (*s1).d.year;
    (*s1).d.year = (*s2).d.year;
    (*s2).d.year = s.d.year;
    s.height= (*s1).height;
    (*s1).height = (*s2).height;
    (*s2).height = s.height;
    s.weight = (*s1).weight;
    (*s1).weight = (*s2).weight;
    (*s2).weight = s.weight;
}

/*This function is used to find the middle record in a linked list by making 
one pointer move at a double pace than the other*/
void middle(struct student* head, struct student** s1, struct student** s2) {
    struct student* x = NULL, *y = NULL;

    if (head == NULL || head->next == NULL) {
        *s1=head;
        *s2=NULL;
    } else {
        x = head;
        y = head->next;
        while (y != NULL) {
            y=y->next;
            if (y != NULL) {
                x = x->next;
                y = y->next;
            }
        }
        *s1 = head;
        *s2 = x->next;
        x->next = NULL;
    }
}

/*This function will combine both the independently sorted linked lists of 
records of student*/
struct student* merge(struct student* a,struct student* b) {
    struct student* final = NULL; // final will store the result of merging 'a' and 'b'

    if (a == NULL)
        return (b);
    else if (b == NULL)
        return (a);
    if (comparison((*a).d, (*(b)).d) == 1) {
        final = a;
        final->next = merge(a->next, b);
    } else {
        final=b;
        final->next = merge(a, b->next);
    }

    return (final);
}

/*Recursive merge sort*/
void mergesort(struct student** Ref) {
    struct student* base = *Ref; /*Ref is a pointer to pointer which will point to 
    the starting record so that we do not lose the reference of the starting 
    record in the process of merging*/
    struct student* a = NULL; //Variable pointer
    struct student* b = NULL; //Variable pointer

    if ((base == NULL) || (base->next == NULL))
        return;
    middle(base, &a, &b);
    mergesort(&a);
    mergesort(&b);
    *Ref = merge(a,b);
}

void main() {
    int m, i;

    scanf("%d", &m);
    printf("%d\n", m);

    for (i = 0; i < m; i++)
        readdata();
    mergesort(&start);
    display();
}

目录 src / main / java 不在类路径上。

需要JavaFX位置，找不到文件

1 个答案: