Flutter 控制屏幕旋轉(zhuǎn)的實(shí)現(xiàn)

更新時間：2020年09月18日 15:30:53 作者：一天清晨

這篇文章主要介紹了Flutter 控制屏幕旋轉(zhuǎn)的實(shí)現(xiàn)，文中通過示例代碼介紹的非常詳細(xì)，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

最近需要做個平板的項(xiàng)目，然后需要直接橫屏，有2種實(shí)現(xiàn)方式。

1, 隨著屏幕旋轉(zhuǎn)，布局自動調(diào)整。做橫豎屏適配

2，強(qiáng)制屏幕橫屏，不隨著屏幕去調(diào)整

第一種方式這里就不做說明了。代碼做適配就可以。下面說一下第二種實(shí)現(xiàn)方式

Flutter 自帶方式

flutter 為我們提供了方法來控制系統(tǒng)的橫豎屏顯示

 SystemChrome.setPreferredOrientations([
   DeviceOrientation.landscapeLeft,
   DeviceOrientation.landscapeRight,
   DeviceOrientation.portraitUp,
   DeviceOrientation.portraitDown
  ]).then((_) {
  });

包含的方向類型。 ?。。?！但是但是但是這個方法只適用于android在iOS上沒有效果，上網(wǎng)查資料有大神封裝的 flutter插件orientation ,flutter插件auto_orientation 在iOS上都起不到效果，所以打算自己寫一個原生文件與flutter進(jìn)行通訊，實(shí)現(xiàn)屏幕旋轉(zhuǎn)。也是筆者在查詢資料之后做的一個整合和解釋說明

iOS端實(shí)現(xiàn)屏幕旋轉(zhuǎn)

創(chuàng)建iOS原生文件

創(chuàng)建iOS原生文件來實(shí)現(xiàn)交互，首先要創(chuàng)建個原生文件。命名為FlutterIOSDevicePlugin。創(chuàng)建文件

創(chuàng)建一個命名為FlutterIOSDevicePlugin.h 和命名為FlutterIOSDevicePlugin.m文件，說明一下： FlutterIOSDevicePlugin.h文件選擇圖片里面的header File模塊創(chuàng)建即可。

創(chuàng)建之后，一起看一下FlutterIOSDevicePlugin.h里面的代碼

#ifndef FlutterIOSDevicePlugin_h
#define FlutterIOSDevicePlugin_h

#import <Flutter/Flutter.h>

@interface FlutterIOSDevicePlugin : NSObject<FlutterPlugin>
+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar flutterViewController:(FlutterViewController*) controller;
- (instancetype)newInstance:(NSObject<FlutterPluginRegistrar>*)registrar flutterViewController:(FlutterViewController*) controller;
@end
#endif /* FlutterIOSDevicePlugin_h */

這個不需要過多說明了看一下FlutterIOSDevicePlugin.m的代碼

#import <Foundation/Foundation.h>
#import "FlutterIOSDevicePlugin.h"

@interface FlutterIOSDevicePlugin () {
  NSObject<FlutterPluginRegistrar> *_registrar;
  FlutterViewController *_controller;
}
@end

static NSString* const CHANNEL_NAME = @"flutter_ios_device";
static NSString* const METHOD_CHANGE_ORIENTATION = @"change_screen_orientation";
static NSString* const ORIENTATION_PORTRAIT_UP = @"portraitUp";
static NSString* const ORIENTATION_PORTRAIT_DOWN = @"portraitDown";
static NSString* const ORIENTATION_LANDSCAPE_LEFT = @"landscapeLeft";
static NSString* const ORIENTATION_LANDSCAPE_RIGHT = @"landscapeRight";

@implementation FlutterIOSDevicePlugin
+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
  FlutterMethodChannel* channel = [FlutterMethodChannel
                   methodChannelWithName:CHANNEL_NAME
                   binaryMessenger:[registrar messenger]];
  FlutterIOSDevicePlugin* instance = [[FlutterIOSDevicePlugin alloc] newInstance:registrar flutterViewController:nil];
  [registrar addMethodCallDelegate:instance channel:channel];
}

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar flutterViewController:(FlutterViewController*) controller {
  FlutterMethodChannel* channel = [FlutterMethodChannel
                   methodChannelWithName:CHANNEL_NAME
                   binaryMessenger:[registrar messenger]];
  FlutterIOSDevicePlugin* instance = [[FlutterIOSDevicePlugin alloc] newInstance:registrar flutterViewController:controller];
  [registrar addMethodCallDelegate:instance channel:channel];
}

- (instancetype)newInstance:(NSObject<FlutterPluginRegistrar>*)registrar flutterViewController:(FlutterViewController*) controller{
  _registrar = registrar;
  _controller = controller;
  return self;
}

- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
  if ([METHOD_CHANGE_ORIENTATION isEqualToString:call.method]) {
    NSArray *arguments = call.arguments;
    NSString *orientation = arguments[0];
    NSNumber *index = [NSNumber numberWithInt: [call.arguments[0] intValue]];
    NSInteger iOSOrientation;
     if ([orientation isEqualToString:ORIENTATION_LANDSCAPE_LEFT]){
           iOSOrientation = UIDeviceOrientationLandscapeLeft;
         }else if([orientation isEqualToString:ORIENTATION_LANDSCAPE_RIGHT]){
           iOSOrientation = UIDeviceOrientationLandscapeRight;
         }else if ([orientation isEqualToString:ORIENTATION_PORTRAIT_DOWN]){
           iOSOrientation = UIDeviceOrientationPortraitUpsideDown;
         }else{
           iOSOrientation = UIDeviceOrientationPortrait;
         }

    [[UIDevice currentDevice] setValue:@(iOSOrientation) forKey:@"orientation"];
//    [[NSNotificationCenter defaultCenter] postNotificationName:@"FlutterIOSDevicePlugin" object:nil userInfo:@{@"orientationMask": index}];
//    [UIViewController attemptRotationToDeviceOrientation];

    result(nil);
  } else {
    result(FlutterMethodNotImplemented);
  }
}
@end

以上是全部的代碼，其中嘗試了用通知的方式去做屏幕旋轉(zhuǎn)，后來發(fā)現(xiàn)其實(shí)沒有那么麻煩，直接采用的是

[[UIDevice currentDevice] setValue:@(iOSOrientation) forKey:@"orientation"];

方式做的。其中遇到的問題：

問題1:iphone手機(jī)上可以正常旋轉(zhuǎn)，ipad上不行

這個問題主要原因是info。plist文件里面的iphone和ipad不一致，且勾選Requires full screen 即可

回到正軌哈

注冊原生插件文件

iOS 工程種有個GeneratedPluginRegistrant.m文件，直接注冊就可以了。如果你項(xiàng)目引入了其他第三方插件，也是統(tǒng)一在這個地方注冊的

#import "GeneratedPluginRegistrant.h"

#if __has_include(<auto_orientation/AutoOrientationPlugin.h>)
#import <auto_orientation/AutoOrientationPlugin.h>
#else
@import auto_orientation;
#endif

#if __has_include(<orientation/OrientationPlugin.h>)
#import <orientation/OrientationPlugin.h>
#else
@import orientation;
#endif
#import "FlutterIOSDevicePlugin.h"

@implementation GeneratedPluginRegistrant

+ (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry {
 [AutoOrientationPlugin registerWithRegistrar:[registry registrarForPlugin:@"AutoOrientationPlugin"]];
 [OrientationPlugin registerWithRegistrar:[registry registrarForPlugin:@"OrientationPlugin"]];
//  [registry registrarForPlugin:@"FlutterIOSDevicePlugin"];
  

  [FlutterIOSDevicePlugin registerWithRegistrar: [registry registrarForPlugin:@"FlutterIOSDevicePlugin"]];
}

@end

代碼中的這個片段是自己寫的插件注冊的方法，其他的AutoOrientationPlugin，OrientationPlugin是引用第三方插件自動生成的代碼。

[FlutterIOSDevicePlugin registerWithRegistrar: [registry registrarForPlugin:@"FlutterIOSDevicePlugin"]];

AppDelegate文件中的設(shè)置

import UIKit
import Flutter



@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
 var orientationMask: UIInterfaceOrientationMask = .all;
  
 override func application(
  _ application: UIApplication,
  didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
 ) -> Bool {
  NotificationCenter.default.addObserver(self, selector: #selector(changeLandscape(center:)), name:NSNotification.Name(rawValue: "FlutterIOSDevicePlugin"), object: nil)
  GeneratedPluginRegistrant.register(with: self);
  return super.application(application, didFinishLaunchingWithOptions: launchOptions)
 }
  override func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
    return orientationMask;
  }
  
  @objc func changeLandscape(center: Notification){
    let index: NSNumber = (center.userInfo?["orientationMask"] ?? 5) as! NSNumber
    var mask : UIInterfaceOrientationMask = .all
    switch index {
    case 0:
      mask = .portrait
      break
    case 1:
      mask = .landscapeLeft
      break
    case 2:
      mask = .landscapeRight
      break
    case 3:
      mask = .portraitUpsideDown
      break
    case 4:
      mask = .landscape
      break
    case 5:
      mask = .all
      break
    case 6:
      mask = .allButUpsideDown
      break
    
    default:
      mask = .all
      break
    }
    orientationMask = mask;
    _ = application(UIApplication.shared, supportedInterfaceOrientationsFor: UIApplication.shared.keyWindow)
  }
}

其中changeLandscape方法是控制監(jiān)聽的事件的方法，目前沒什么用。主要代碼是這一段，這個是在發(fā)出屏幕旋轉(zhuǎn)的時候回調(diào)的方法，這里面設(shè)置的是全部的方向都可以。

  override func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
    return orientationMask;
  }

問題2:程序不走該方法

具體原因是因?yàn)閕nfo.plist文件問題。參考上面設(shè)置就沒問題

flutter 原生代碼使用

這個地方是針對于iOS平臺去做的區(qū)別。

MethodChannel _channel = const MethodChannel('flutter_ios_device');

@override
 void initState() {
  SystemChrome.setPreferredOrientations([
   DeviceOrientation.landscapeLeft,
   DeviceOrientation.landscapeRight,
   DeviceOrientation.portraitUp,
   DeviceOrientation.portraitDown
  ]).then((_) {
   if (Platform.isIOS) {
    this.changeScreenOrientation(DeviceOrientation.landscapeLeft);
   }
  });
  super.initState();
 }
 
Future<void> changeScreenOrientation(DeviceOrientation orientation) {
  String o;
  switch (orientation) {
   case DeviceOrientation.portraitUp:
    o = 'portraitUp';
    break;
   case DeviceOrientation.portraitDown:
    o = 'portraitDown';
    break;
   case DeviceOrientation.landscapeLeft:
    o = 'landscapeLeft';
    break;
   case DeviceOrientation.landscapeRight:
    o = 'landscapeRight';
    break;
  }
  return _channel.invokeMethod('change_screen_orientation', [o]);
 }

代碼不用過多說明了，有不了解的可以留言

問題3: 啟動程序自動旋轉(zhuǎn)

SystemChrome.setPreferredOrientations需要設(shè)置全部內(nèi)容。不然會默認(rèn)旋轉(zhuǎn)。有點(diǎn)小坑，

以上基本上可以實(shí)現(xiàn)屏幕旋轉(zhuǎn)的問題，如果有小伙伴還是不行，可以試一下用iOS原生通知的方式去完成。這個我做的是平板的項(xiàng)目，暫時沒有問題，更多相關(guān)Flutter 控制屏幕旋轉(zhuǎn)內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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