1.Flutter 设置
在 main 函数 加载app前添加以下代码
SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ])添加后的结果
void main() async {
  WidgetsBinding widgetsBinding = WidgetsFlutterBinding.ensureInitialized();
   
    // 在此处添加代码
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);
  runApp(App());
}*上面的代码 可以应对很多情况,但是在ipad 中 可能会失效。android pad 没问题。 为了避免出现问题可以在adnroid、ios 系统层面设置
Android - app-> main- > src -> AndroidManifest.xml
在activity 标签中增加
android:screenOrientation="portrait"添加后的样子
<activity
            android:name=".MainActivity"
            android:exported="true"
            android:launchMode="singleTop"
            android:screenOrientation="portrait"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:windowSoftInputMode="adjustResize">
.......Ios - Runner -> Info.plist
Iphone: 在 <key>UISupportedInterfaceOrientations</key> 标签中增加
<array>
			<!-- <string>UIInterfaceOrientationPortrait</string>
			<string>UIInterfaceOrientationLandscapeLeft</string>
			<string>UIInterfaceOrientationLandscapeRight</string> -->
			<string>UIInterfaceOrientationPortraitUpsideDown</string>
		</array>如果已经存在 你要注释掉 左右 标签。
Ipad <key>UISupportedInterfaceOrientations~ipad</key> 此标签 是设置ipad 屏幕转向的
<array>
			<!-- <string>UIInterfaceOrientationPortrait</string> -->
			<string>UIInterfaceOrientationPortraitUpsideDown</string>
			<!-- <string>UIInterfaceOrientationLandscapeLeft</string>
			<string>UIInterfaceOrientationLandscapeRight</string> -->
		</array>以上标签,没有的添加上 已经存在的 进行修改即可。
最终样子:
<key>UISupportedInterfaceOrientations</key>
		<array>
			<!-- <string>UIInterfaceOrientationPortrait</string>
			<string>UIInterfaceOrientationLandscapeLeft</string>
			<string>UIInterfaceOrientationLandscapeRight</string> -->
			<string>UIInterfaceOrientationPortraitUpsideDown</string>
		</array>
		<key>UISupportedInterfaceOrientations~ipad</key>
		<array>
			<!-- <string>UIInterfaceOrientationPortrait</string> -->
			<string>UIInterfaceOrientationPortraitUpsideDown</string>
			<!-- <string>UIInterfaceOrientationLandscapeLeft</string>
			<string>UIInterfaceOrientationLandscapeRight</string> -->
		</array>