在扫描了关于这个主题的所有线程之后，没有一个建议可以解决这个问题。奇怪的是，这个问题只是突然浮出水面，似乎没有明显的原因。昨晚效果很好。
导航基本上是：
/-Navigation Controller -> View -> View (this last connection doesn't fire. Pushing the "next" button results in nothing.
/
TabBarController ---- Navigation Controller -> View -> View (works)
\
\
\-Same as above. (works)
据我所知，设置是相同的，我已经完成了删除/清理/重建有问题的视图和连接的繁忙工作，但没有成功。
这是我的故事板 XML 中的（希望是）相关部分
<!--TDC2-->
<scene sceneID="ing-Ye-PVs">
<objects>
<viewController id="dNt-CQ-X0M" customClass="TDC2" sceneMemberID="viewController">
<view key="view" contentMode="scaleToFill" id="ZIK-gx-Nq4">
<rect key="frame" x="0.0" y="20" width="320" height="460"/>
<autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
<subviews>
<textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" borderStyle="line" placeholder="Trip Number" textAlignment="center" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="xbU-au-gtQ">
<constraints>
<constraint firstAttribute="height" constant="43" id="iMS-ez-xo8"/>
</constraints>
<fontDescription key="fontDescription" type="system" pointSize="14"/>
<textInputTraits key="textInputTraits" keyboardType="numberPad"/>
<connections>
<outlet property="delegate" destination="dNt-CQ-X0M" id="DU2-gu-IxO"/>
</connections>
</textField>
<textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" borderStyle="line" placeholder="Departure" textAlignment="center" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="B5M-Ti-5nL">
<constraints>
<constraint firstAttribute="height" constant="43" id="aUt-lR-eT8"/>
</constraints>
<fontDescription key="fontDescription" type="system" pointSize="14"/>
<textInputTraits key="textInputTraits"/>
<connections>
<outlet property="delegate" destination="dNt-CQ-X0M" id="XyV-Of-fnR"/>
</connections>
</textField>
<textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" borderStyle="line" placeholder="Out Fuel" textAlignment="center" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="yxx-QE-lRo">
<constraints>
<constraint firstAttribute="height" constant="43" id="i11-f6-Kco"/>
</constraints>
<fontDescription key="fontDescription" type="system" pointSize="14"/>
<textInputTraits key="textInputTraits"/>
<connections>
<outlet property="delegate" destination="dNt-CQ-X0M" id="SPC-XB-pOD"/>
</connections>
</textField>
<textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" borderStyle="line" placeholder="Start Hobbs" textAlignment="center" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="wAx-ux-6y5">
<constraints>
<constraint firstAttribute="height" constant="43" id="la9-aF-SWs"/>
</constraints>
<fontDescription key="fontDescription" type="system" pointSize="14"/>
<textInputTraits key="textInputTraits" keyboardType="numberPad"/>
<connections>
<outlet property="delegate" destination="dNt-CQ-X0M" id="4UI-cl-zxC"/>
</connections>
</textField>
<segmentedControl opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="top" segmentControlStyle="plain" selectedSegmentIndex="0" translatesAutoresizingMaskIntoConstraints="NO" id="PXM-z4-ndS">
<segments>
<segment title="PIC"/>
<segment title="SIC"/>
</segments>
</segmentedControl>
<label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" text="Who is flying?" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="frD-Qe-Ib9">
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" text="Trip" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Fuc-2m-9Zy">
<constraints>
<constraint firstAttribute="width" constant="30" id="7cK-5c-HM9"/>
</constraints>
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" text="Depart" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="uvI-4w-aME">
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" text="Fuel" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="fY7-7H-utj">
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
<nil key="highlightedColor"/>
</label>
<label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" text="Hobbs" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="WI2-MH-Xfw">
<fontDescription key="fontDescription" type="system" pointSize="17"/>
<color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
<nil key="highlightedColor"/>
</label>
</subviews>
<color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
<gestureRecognizers/>
<constraints>
<constraint firstItem="fY7-7H-utj" firstAttribute="centerY" secondItem="yxx-QE-lRo" secondAttribute="centerY" type="default" id="33E-Ci-sZT"/>
<constraint firstAttribute="trailing" secondItem="B5M-Ti-5nL" secondAttribute="trailing" constant="20" symbolic="YES" type="default" id="4YK-YK-l5r"/>
<constraint firstItem="fY7-7H-utj" firstAttribute="baseline" secondItem="yxx-QE-lRo" secondAttribute="baseline" type="default" id="4eX-Xh-6rd"/>
<constraint firstItem="wAx-ux-6y5" firstAttribute="top" secondItem="yxx-QE-lRo" secondAttribute="bottom" constant="8" symbolic="YES" type="default" id="4pq-KW-vdv"/>
<constraint firstItem="B5M-Ti-5nL" firstAttribute="top" secondItem="xbU-au-gtQ" secondAttribute="bottom" constant="8" symbolic="YES" type="default" id="6Dc-8Z-L4q"/>
<constraint firstItem="yxx-QE-lRo" firstAttribute="top" secondItem="B5M-Ti-5nL" secondAttribute="bottom" constant="8" symbolic="YES" type="default" id="7HV-va-Jwi"/>
<constraint firstItem="Fuc-2m-9Zy" firstAttribute="leading" secondItem="ZIK-gx-Nq4" secondAttribute="leading" constant="42" id="90D-A5-UCb"/>
<constraint firstItem="frD-Qe-Ib9" firstAttribute="centerX" secondItem="PXM-z4-ndS" secondAttribute="centerX" type="default" id="9Df-Ov-WRu"/>
<constraint firstItem="frD-Qe-Ib9" firstAttribute="top" secondItem="wAx-ux-6y5" secondAttribute="bottom" constant="8" symbolic="YES" type="default" id="ERP-rE-3ih"/>
<constraint firstAttribute="trailing" secondItem="yxx-QE-lRo" secondAttribute="trailing" constant="20" symbolic="YES" type="default" id="Ibi-pB-iAX"/>
<constraint firstItem="WI2-MH-Xfw" firstAttribute="centerY" secondItem="wAx-ux-6y5" secondAttribute="centerY" type="default" id="JXF-d6-wg8"/>
<constraint firstAttribute="trailing" secondItem="PXM-z4-ndS" secondAttribute="trailing" constant="20" symbolic="YES" type="default" id="K0y-pX-ZFf"/>
<constraint firstItem="wAx-ux-6y5" firstAttribute="leading" secondItem="WI2-MH-Xfw" secondAttribute="trailing" constant="8" symbolic="YES" type="default" id="P6r-KM-Uj7"/>
<constraint firstItem="Fuc-2m-9Zy" firstAttribute="centerY" secondItem="xbU-au-gtQ" secondAttribute="centerY" type="default" id="RhF-sp-4Ru"/>
<constraint firstItem="xbU-au-gtQ" firstAttribute="leading" secondItem="B5M-Ti-5nL" secondAttribute="leading" type="default" id="Rx5-ms-1N7"/>
<constraint firstAttribute="trailing" secondItem="wAx-ux-6y5" secondAttribute="trailing" constant="20" symbolic="YES" type="default" id="Tth-zq-zVg"/>
<constraint firstItem="PXM-z4-ndS" firstAttribute="leading" secondItem="ZIK-gx-Nq4" secondAttribute="leading" constant="20" symbolic="YES" type="default" id="Z1c-rB-axa"/>
<constraint firstItem="Fuc-2m-9Zy" firstAttribute="baseline" secondItem="xbU-au-gtQ" secondAttribute="baseline" type="default" id="aU1-zo-HBe"/>
<constraint firstItem="xbU-au-gtQ" firstAttribute="top" secondItem="ZIK-gx-Nq4" secondAttribute="top" constant="20" symbolic="YES" type="default" id="e3G-YD-OOE"/>
<constraint firstItem="wAx-ux-6y5" firstAttribute="leading" secondItem="yxx-QE-lRo" secondAttribute="leading" type="default" id="fpp-at-Fis"/>
<constraint firstItem="yxx-QE-lRo" firstAttribute="leading" secondItem="fY7-7H-utj" secondAttribute="trailing" constant="8" symbolic="YES" type="default" id="ifT-MI-4hR"/>
<constraint firstAttribute="trailing" secondItem="xbU-au-gtQ" secondAttribute="trailing" constant="20" symbolic="YES" type="default" id="jNt-zD-oTI"/>
<constraint firstItem="uvI-4w-aME" firstAttribute="baseline" secondItem="B5M-Ti-5nL" secondAttribute="baseline" type="default" id="kmY-Ol-p7p"/>
<constraint firstItem="yxx-QE-lRo" firstAttribute="leading" secondItem="B5M-Ti-5nL" secondAttribute="leading" type="default" id="mI4-Zu-iNP"/>
<constraint firstItem="PXM-z4-ndS" firstAttribute="top" secondItem="frD-Qe-Ib9" secondAttribute="bottom" constant="8" symbolic="YES" type="default" id="qGW-ek-yZd"/>
<constraint firstItem="uvI-4w-aME" firstAttribute="top" secondItem="ZIK-gx-Nq4" secondAttribute="top" constant="81" id="uaR-8Y-5QN"/>
<constraint firstItem="xbU-au-gtQ" firstAttribute="leading" secondItem="Fuc-2m-9Zy" secondAttribute="trailing" constant="8" symbolic="YES" type="default" id="ujE-gd-4M9"/>
<constraint firstItem="uvI-4w-aME" firstAttribute="leading" secondItem="ZIK-gx-Nq4" secondAttribute="leading" constant="20" symbolic="YES" type="default" id="w3k-jd-ax9"/>
</constraints>
</view>
<navigationItem key="navigationItem" id="2nj-Ip-nf5">
<barButtonItem key="leftBarButtonItem" title="Back" id="tVS-8H-FUI"/>
<barButtonItem key="rightBarButtonItem" title="Next" id="1JK-F2-zOK"/>
</navigationItem>
<connections>
<outlet property="departure" destination="B5M-Ti-5nL" id="AWa-Ws-aD3"/>
<outlet property="outFuel" destination="yxx-QE-lRo" id="K6r-M4-Rlz"/>
<outlet property="startHobbs" destination="wAx-ux-6y5" id="Dyn-O8-9Hh"/>
<outlet property="tripNumber" destination="xbU-au-gtQ" id="AZA-T4-Izz"/>
<outlet property="whosFlying" destination="PXM-z4-ndS" id="VKX-zm-stJ"/>
<segue destination="VZ0-Ck-hG8" kind="push" id="pCS-hs-xSz"/>
</connections>
</viewController>
<placeholder placeholderIdentifier="IBFirstResponder" id="Gtn-Vk-tyE" userLabel="First Responder" sceneMemberID="firstResponder"/>
</objects>
<point key="canvasLocation" x="1133" y="740"/>
</scene>
<!--View Controller-->
<scene sceneID="6on-A1-vuU">
<objects>
<viewController id="VZ0-Ck-hG8" sceneMemberID="viewController">
<view key="view" contentMode="scaleToFill" id="YmM-zs-zBh">
<rect key="frame" x="0.0" y="20" width="320" height="460"/>
<autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
<color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
</view>
<navigationItem key="navigationItem" id="g9K-Xz-a2H"/>
</viewController>
<placeholder placeholderIdentifier="IBFirstResponder" id="UYI-Pa-J93" userLabel="First Responder" sceneMemberID="firstResponder"/>
</objects>
<point key="canvasLocation" x="1670" y="745"/>
</scene>