由于Flutter 的渲染机制。直接使用FlutterViewController去显示界面 会造成2M左右的内存无法释放问题。每次显示 关闭都会出现这个问题。内存泄漏。
使用单例对FlutterViewController进行全局化 会解决这个问题。一旦生成则不会被释放

原生与Flutter 代码的Channel通道代码需要一直

使用
 [[JWFlutterManager shareInstance] pushViewControllerTag:@"页面名字" viewController:self];
 
.h
#import <Flutter/Flutter.h>

NS_ASSUME_NONNULL_BEGIN

@interface JWFlutterManager : NSObject
+(instancetype)shareInstance;
//  所需要显示的页面名
-(void)pushViewControllerTag:(NSString*)tag pushViewControllerTag:(UIViewController*)controller;
@end
 


.m
#import "JWFlutterManager.h"
#import <Flutter/Flutter.h>
#import <FlutterPluginRegistrant/GeneratedPluginRegistrant.h>
#import "JWFlutterViewController.h"
@interface JWFlutterManager()
@property(nonatomic, strong) FlutterEngine* flutterEngine;
@property(nonatomic, strong) JWFlutterViewController * flutterVc;
@property(nonatomic, strong) FlutterMethodChannel * myMethodChannel;
@property(nonatomic, strong) FlutterBasicMessageChannel* messageChannel;
@end
@implementation JWFlutterManager
+(instancetype)shareInstance{
    static JWFlutterManager *flutterManager = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        flutterManager = [JWFlutterManager new];
        [flutterManager flutterConfiger];
    });
    return flutterManager;
}
-(void)flutterConfiger{
    self.flutterVc = [[JWFlutterViewController alloc] initWithEngine:self.flutterEngine nibName:nil bundle:nil];
    self.flutterVc.title = @"我的任务";
    self.flutterVc.modalPresentationStyle = 0;
    
    self.messageChannel = [FlutterBasicMessageChannel messageChannelWithName:@"接收点击消息Tag" binaryMessenger:self.flutterVc];
    // 接收消息监听
    __weak typeof(self) weakSelf = self;
    [self.messageChannel setMessageHandler:^(id message, FlutterReply callback) {
        NSString *messageId = message;
        NSLog(@"收到flutter传递的消息：%@",messageId);
        
    }];
      
}
   
-(void)pushViewControllerTag:(NSString*)tag pushViewControllerTag:(UIViewController*)controller{
    [self.messageChannel sendMessage:[self baseParams]];
    
    FlutterMethodChannel * methodChannel = [FlutterMethodChannel methodChannelWithName:@"页面间的消息Tag" binaryMessenger:self.flutterVc];
    [methodChannel invokeMethod:tag arguments:nil];
    _myMethodChannel = methodChannel;
    [self.flutterVc flutterViewController:tag];
    self.flutterVc.myMethodChannel = _myMethodChannel;
     
  [controller.navigationController pushViewController:self.flutterVc animated:YES];
  
}
 
 
// 网络配置
-(NSDictionary*)baseParams{
    
    // 获取参数
    NSMutableDictionary *params = @{};
     
    NSDictionary *dic = @{@"baseURL":@"",
                          @"baseParam":params
    }; 
    return dic; 
}
-(FlutterEngine *)flutterEngine
{
    if (_flutterEngine == nil) {
        FlutterEngine * flutterEngine = [[FlutterEngine alloc] initWithName:@"flutter_engine"];
        [flutterEngine runWithEntrypoint:nil];
        [GeneratedPluginRegistrant registerWithRegistry:flutterEngine];
        _flutterEngine = flutterEngine;
    }
    return _flutterEngine;
}
@end


// JWFlutterManager.h 继承 FlutterViewController 可控性大
.h
#import <Flutter/Flutter.h>
#import "JWFlutterManager.h"
NS_ASSUME_NONNULL_BEGIN

@interface JWFlutterViewController : FlutterViewController
@property(nonatomic, strong) FlutterMethodChannel * myMethodChannel;
-(void)flutterViewController:(NSString*)pageName; 
@end


.m

#import "JWFlutterViewController.h"
@interface JWFlutterViewController ()
@property (nonatomic,copy) NSString *pageName;

@end

@implementation JWFlutterViewController
  
-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    if(self.pageName){
      // 页面刷新
        [self.myMethodChannel invokeMethod:self.pageName arguments:nil];
    }
     
}
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
     
}
-(void)flutterViewController:(NSString*)pageName{
    self.pageName = pageName;
}
  
-(void)dealloc{
    NSLog(@"------JWFlutterViewController-----dealloc------");
}
@end