所以我试图用 Swift 为学校项目制作一个应用程序。（我对这种语言完全陌生）该应用程序应该允许您倾斜您的设备，并通过这样做使一个正方形下降到屏幕底部。这就是 ip 现在使用的内容：
func gravityUpdated(){
if let data = motionManager.deviceMotion {
let gravity = data.gravity
Zwaartekracht.gravityDirection = CGVectorMake(CGFloat(gravity.x), CGFloat(gravity.y))
}
}
gravityUpdated()
当我在我的 iPhone 6 上运行它时，构建是成功的，但后来我看到了这个：（对不起，很长的帖子）：
libswiftCore.dylib`function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded, Arg[2] = Dead, Arg[3] = Dead> of Swift._fatalErrorMessage (Swift.StaticString, Swift.StaticString, Swift.StaticString, Swift.UInt) -> ():
0x100171448 <+0>: stp x29, x30, [sp, #-16]!
0x10017144c <+4>: mov x29, sp
0x100171450 <+8>: sub sp, sp, #16
0x100171454 <+12>: and w8, w2, #0x1
0x100171458 <+16>: tbnz w8, #0, 0x100171478 ; <+48>
0x10017145c <+20>: tbnz x1, #63, 0x100171568 ; <+288>
0x100171460 <+24>: add x1, x0, x1
0x100171464 <+28>: mov x2, x3
0x100171468 <+32>: mov x3, x4
0x10017146c <+36>: mov x4, x5
0x100171470 <+40>: bl 0x1001a1334 ; function signature specialization <Arg[0] = Exploded, Arg[1] = Exploded> of Swift.(_fatalErrorMessage (Swift.StaticString, Swift.StaticString, Swift.StaticString, Swift.UInt) -> ()).(closure #2)
-> 0x100171474 <+44>: brk #0x1
0x100171478 <+48>: str xzr, [sp, #8]
0x10017147c <+52>: cmp x0, w0, uxtw
0x100171480 <+56>: b.ne 0x100171620 ; <+472>
0x100171484 <+60>: lsr w8, w0, #11
0x100171488 <+64>: cmp w8, #27
0x10017148c <+68>: b.ne 0x1001714b4 ; <+108>
0x100171490 <+72>: adr x0, #584602 ; "fatal error"
0x100171494 <+76>: nop
0x100171498 <+80>: adr x3, #586600 ; "high- and low-surrogate code points are not valid Unicode scalar values"
0x10017149c <+84>: nop
0x1001714a0 <+88>: movz w1, #0xb
0x1001714a4 <+92>: orr w2, wzr, #0x2
0x1001714a8 <+96>: movz w4, #0x47
0x1001714ac <+100>: orr w5, wzr, #0x2
0x1001714b0 <+104>: bl 0x100171448 ; <+0>
0x1001714b4 <+108>: lsr w10, w0, #16
0x1001714b8 <+112>: cmp w10, #16
0x1001714bc <+116>: b.hi 0x1001714ec ; <+164>
0x1001714c0 <+120>: cmp w0, #128
0x1001714c4 <+124>: b.lo 0x100171510 ; <+200>
0x1001714c8 <+128>: orr w8, wzr, #0x80
0x1001714cc <+132>: bfxil x8, x0, #0, #6
0x1001714d0 <+136>: cmp w0, #2047
0x1001714d4 <+140>: b.hi 0x10017158c ; <+324>
0x1001714d8 <+144>: movz x11, #0
0x1001714dc <+148>: movz x10, #0
0x1001714e0 <+152>: lsr w9, w0, #6
0x1001714e4 <+156>: orr w9, w9, #0xffffffc0
0x1001714e8 <+160>: b 0x1001715e8 ; <+416>
0x1001714ec <+164>: adr x0, #584510 ; "fatal error"
0x1001714f0 <+168>: nop
0x1001714f4 <+172>: adr x3, #586588 ; "value is outside of Unicode codespace"
0x1001714f8 <+176>: nop
0x1001714fc <+180>: movz w1, #0xb
0x100171500 <+184>: orr w2, wzr, #0x2
0x100171504 <+188>: movz w4, #0x25
0x100171508 <+192>: orr w5, wzr, #0x2
0x10017150c <+196>: bl 0x100171448 ; <+0>
0x100171510 <+200>: movz x10, #0
0x100171514 <+204>: movz x9, #0
0x100171518 <+208>: mov x8, x0
0x10017151c <+212>: orr w11, wzr, #0x8
0x100171520 <+216>: umulh x11, x9, x11
0x100171524 <+220>: cmp xzr, x11
0x100171528 <+224>: cset w11, ne
0x10017152c <+228>: tbnz w11, #0, 0x100171620 ; <+472>
0x100171530 <+232>: lsl x11, x9, #3
0x100171534 <+236>: cmp x11, #63
0x100171538 <+240>: b.hi 0x100171624 ; <+476>
0x10017153c <+244>: and x8, x8, #0xff
0x100171540 <+248>: lsl x8, x8, x11
0x100171544 <+252>: orr x8, x8, x10
0x100171548 <+256>: str x8, [sp, #8]
0x10017154c <+260>: cmn x9, #2
0x100171550 <+264>: b.le 0x100171568 ; <+288>
0x100171554 <+268>: add x8, sp, #8
0x100171558 <+272>: add x8, x9, x8
0x10017155c <+276>: add x1, x8, #1
0x100171560 <+280>: add x0, sp, #8
0x100171564 <+284>: b 0x100171464 ; <+28>
0x100171568 <+288>: adr x0, #584386 ; "fatal error"
0x10017156c <+292>: nop
0x100171570 <+296>: adr x3, #584656 ; "UnsafeBufferPointer with negative count"
0x100171574 <+300>: nop
0x100171578 <+304>: movz w1, #0xb
0x10017157c <+308>: orr w2, wzr, #0x2
0x100171580 <+312>: movz w4, #0x27
0x100171584 <+316>: orr w5, wzr, #0x2
0x100171588 <+320>: bl 0x100171448 ; <+0>
0x10017158c <+324>: orr w9, wzr, #0xffffff80
0x100171590 <+328>: bfxil w9, w0, #6, #6
0x100171594 <+332>: cbnz w10, 0x1001715ac ; <+356>
0x100171598 <+336>: movz x11, #0
0x10017159c <+340>: movz x12, #0
0x1001715a0 <+344>: lsr w10, w0, #12
0x1001715a4 <+348>: orr w10, w10, #0xffffffe0
0x1001715a8 <+352>: b 0x1001715d0 ; <+392>
0x1001715ac <+356>: lsr w10, w0, #18
0x1001715b0 <+360>: orr w11, w10, #0xf0
0x1001715b4 <+364>: cmp w11, w11, uxtb
0x1001715b8 <+368>: b.ne 0x100171620 ; <+472>
0x1001715bc <+372>: orr w10, wzr, #0xffffff80
0x1001715c0 <+376>: bfxil w10, w0, #12, #6
0x1001715c4 <+380>: and x12, x11, #0xff
0x1001715c8 <+384>: str x12, [sp, #8]
0x1001715cc <+388>: orr w11, wzr, #0x1
0x1001715d0 <+392>: and x10, x10, #0xff
0x1001715d4 <+396>: lsl x13, x11, #3
0x1001715d8 <+400>: lsl x10, x10, x13
0x1001715dc <+404>: orr x10, x10, x12
0x1001715e0 <+408>: str x10, [sp, #8]
0x1001715e4 <+412>: add x11, x11, #1
0x1001715e8 <+416>: orr w12, wzr, #0x8
0x1001715ec <+420>: umulh x12, x11, x12
0x1001715f0 <+424>: cmp xzr, x12
0x1001715f4 <+428>: cset w12, ne
0x1001715f8 <+432>: tbnz w12, #0, 0x100171620 ; <+472>
0x1001715fc <+436>: lsl x12, x11, #3
0x100171600 <+440>: cmp x12, #64
0x100171604 <+444>: b.hs 0x100171624 ; <+476>
0x100171608 <+448>: and x9, x9, #0xff
0x10017160c <+452>: lsl x9, x9, x12
0x100171610 <+456>: orr x10, x9, x10
0x100171614 <+460>: str x10, [sp, #8]
0x100171618 <+464>: add x9, x11, #1
0x10017161c <+468>: tbz x9, #63, 0x10017151c ; <+212>
0x100171620 <+472>: brk #0x1
0x100171624 <+476>: adr x0, #584198 ; "fatal error"
0x100171628 <+480>: nop
0x10017162c <+484>: adr x3, #584228 ; "shift amount is larger than type size in bits"
0x100171630 <+488>: nop
0x100171634 <+492>: movz w1, #0xb
0x100171638 <+496>: orr w2, wzr, #0x2
0x10017163c <+500>: movz w4, #0x2d
0x100171640 <+504>: orr w5, wzr, #0x2
0x100171644 <+508>: bl 0x100171448 ; <+0>
在底部它还指出：fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)
我不知道这是怎么发生的
有人可以帮忙吗？谢谢！