Flutter常見(jiàn)問(wèn)題匯總

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目錄

1. Mac os 10.15 運(yùn)行‘idevice_id’無(wú)法驗(yàn)證開(kāi)發(fā)者
2. json數(shù)據(jù)轉(zhuǎn)換
3. TextField鍵盤(pán)顯示隱藏
4. 橫豎屏設(shè)置
5. TextField光標(biāo)文字焦點(diǎn)不對(duì)齊問(wèn)題
6. ios打包白屏
7. 圖片充滿父視圖
8. 運(yùn)行報(bào)錯(cuò)：Unhandled Exception: ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.
9. showModalBottomSheet頂部圓角
10. 限制TextField輸入長(zhǎng)度（使用maxLength會(huì)有counter控件）
11. 背景圖會(huì)被鍵盤(pán)頂起
12. ios Cocoapods報(bào)錯(cuò)： NoMethodError - undefined method `size' for nil:NilClass
13. setState更新數(shù)據(jù)，PageView、ListView等子控件沒(méi)更新

解決方案

• 1. Mac os 10.15 運(yùn)行‘idevice_id’無(wú)法驗(yàn)證開(kāi)發(fā)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

替換為自己的路徑

• 2. json數(shù)據(jù)轉(zhuǎn)換
     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();

• 3. TextField鍵盤(pán)顯示隱藏

// 顯示鍵盤(pán)
focusNode.requestFocus();
// 隱藏鍵盤(pán)
focusNode.unfocus();

• 4. 橫豎屏設(shè)置

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

• 5. TextField光標(biāo)文字焦點(diǎn)不對(duì)齊問(wèn)題

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

• 6. ios打包白屏

1. 在項(xiàng)目下終端運(yùn)行：
flutter build ios --release
2. 在Xcode中打開(kāi)項(xiàng)目， Product -> Archive 即可 

7. 圖片充滿父視圖

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

8. 運(yùn)行報(bào)錯(cuò)：Unhandled Exception: ServicesBinding.defaultBinaryMessenger was accessed before the binding was initialized.

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

9. showModalBottomSheet頂部圓角

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

10. 限制TextField輸入長(zhǎng)度（使用maxLength會(huì)有counter控件）

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

11. 背景圖會(huì)被鍵盤(pán)頂起

Scaffold中設(shè)置：
resizeToAvoidBottomInset: false,

12. ios Cocoapods報(bào)錯(cuò)： 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 /// 加上這個(gè)

13. setState更新數(shù)據(jù)，PageView、ListView等子控件沒(méi)更新
    詳見(jiàn)：http://www.itdecent.cn/p/977e1448f95d