Flutter常见问题汇总

欢迎加群交流（qq:839981465）

Mac os 10.15 运行‘idevice_id’无法验证开发者
json数据转换
TextField键盘显示隐藏
横竖屏设置
TextField光标文字焦点不对齐问题
ios打包白屏
图片充满父视图
运行报错：Unhandled Exception: ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.
showModalBottomSheet顶部圆角
限制TextField输入长度（使用maxLength会有counter控件）
背景图会被键盘顶起
ios Cocoapods报错： NoMethodError - undefined method `size' for nil:NilClass
setState更新数据，PageView、ListView等子控件没更新

解决方案

1. Mac os 10.15 运行‘idevice_id’无法验证开发者
  
  1576138438797.jpg

sudo xattr -d com.apple.quarantine [your_path]/flutter/bin/cache/artifacts/libimobiledevice/idevice_id
sudo xattr -d com.apple.quarantine [your_path]/flutter/bin/cache/artifacts/libimobiledevice/ideviceinfo
sudo xattr -d com.apple.quarantine [your_path]/flutter/bin/cache/artifacts/libimobiledevice/idevicesyslog
sudo xattr -d com.apple.quarantine [your_path]/flutter/bin/cache/artifacts/usbmuxd/iproxy

替换为自己的路径

1. json数据转换
  json_to_dart

// 使用范例：
var list = json.decode(widget.itemBean.formDefaultValue);
  var items = (list as List).cast().map((value) {
  return Bean.formJson(value);
}).toList();

1. TextField键盘显示隐藏

// 显示键盘
focusNode.requestFocus();
// 隐藏键盘
focusNode.unfocus();

1. 横竖屏设置

SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown
  ]);
runApp(MyApp());

1. TextField光标文字焦点不对齐问题

TextField(
   style: TextStyle(textBaseline: TextBaseline.alphabetic),
)

1. ios打包白屏

1. 在项目下终端运行：
flutter build ios --release
2. 在Xcode中打开项目， Product -> Archive 即可

图片充满父视图

ConstrainedBox(
        child: Image.asset(
                  AssetImages.start2,
                  fit: BoxFit.cover,
                  ),
        constraints: new BoxConstraints.expand(),
       )

运行报错：Unhandled Exception: ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.

void main() {
  // 加上这句即可
  WidgetsFlutterBinding.ensureInitialized();
  //
  runApp(MyApp());
}

showModalBottomSheet顶部圆角

    showModalBottomSheet(
      context: context,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(10),
      ),
      builder: (context) {
        return Container();
      },
    )

限制TextField输入长度（使用maxLength会有counter控件）

inputFormatters: <TextInputFormatter>[
          LengthLimitingTextInputFormatter(6)
        ],

背景图会被键盘顶起

Scaffold中设置：
resizeToAvoidBottomInset: false,

ios Cocoapods报错： NoMethodError - undefined method `size' for nil:NilClass

flutter clean
rm -Rf ios/Pods
rm -Rf ios/.symlinks
rm -Rf ios/Flutter/Flutter.framework
rm -Rf ios/Flutter/Flutter.podspec
rm -Rf ios/Podfile.lock /// 加上这个

setState更新数据，PageView、ListView等子控件没更新
详见：https://www.jianshu.com/p/977e1448f95d

Flutter常见问题汇总

Flutter常见问题汇总

目录

解决方案