之前Flutter項目都妥妥的，升級Xcode11.4後卻報錯。
error: Building for iOS, but the linked and embedded framework 'App.framework' was built for iOS Simulator. (in target 'Runner' from project 'Runner')
別急，首先Clean下項目，在項目根目錄下：
flutter clean
然後刪除ios/Flutter/App.framework：
rm -rf ios/Flutter/App.framework
再次運行，應該就OK了。
如果還是不行的話，雙擊ios/Runner.xcworkspace。在Xcode左側Navigator中，刪除App.framework和Flutter.framework。
在Runner Target -> Build Phases -> Link Binary With Libraries和Embed Frameworks中，確認下圖紅框中沒有App.framework和Flutter.framework。
將Build Phases -> Thin Binary中的腳本改爲如下：
/bin/sh "$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh" embed
/bin/sh "$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh" thin
切換到Runner Target的Build Settings面板，雙擊Other Linker Flags項，在彈出窗口中點擊**+**號，並輸入：
$(inherited) -framework Flutter
