example4, loadmore 会触发多次，加载完成后 “加载中不消失”

[zhangjianlin77]

环境如下
[✓] Flutter (Channel master, v0.7.0, on Mac OS X 10.12.6 16G29, locale zh-Hans-CN)
[✓] Android toolchain - develop for Android devices (Android SDK 28.0.0-rc1)
[!] iOS toolchain - develop for iOS devices (Xcode 9.2)
✗ libimobiledevice and ideviceinstaller are not installed. To install, run:
brew install --HEAD libimobiledevice
brew install ideviceinstaller
✗ ios-deploy not installed. To install:
brew install ios-deploy
! CocoaPods out of date (1.5.0 is recommended).
CocoaPods is used to retrieve the iOS platform side's plugin code that responds to your plugin usage on the Dart side.
Without resolving iOS dependencies with CocoaPods, plugins will not work on iOS.
For more info, see https://flutter.io/platform-plugins
To upgrade:
brew upgrade cocoapods
pod setup
[✓] Android Studio (version 2.3)
✗ Flutter plugin version 12.1 - the recommended minimum version is 16.0.0
[!] VS Code (version 1.26.1)
[✓] Connected devices (1 available)

example4加载更多有几个bug

! Doctor found issues in 2 categories.

[zhangjianlin77]

加个这样的可以解决 上滑也会触发 loadmore问题

//check user is pulling up
bool _isPullUp(ScrollNotification noti) {
print("_isPullUp $noti");
return noti.metrics.extentBefore == 0.0 &&
noti.metrics.pixels < 0;
}

//check user is pulling down
bool _isPullDown(ScrollNotification noti) {
print("_isPullUp $noti");
return noti.metrics.extentAfter == 0.0 &&
noti.metrics.pixels > 0;
}

[nanchaodong]

bool _isPullUp(ScrollNotification noti) {
print("_isPullUp $noti");
return noti.metrics.extentBefore == 0.0 &&
noti.metrics.pixels < 0;
}

ScrollNotification 从哪里来的