Flutter的plugin中对AppDelegate中的方法进行拦截_ios registrar addapplicationdelegate:instance

如果在Plugin中增加下面的代码，增加对AppDelegate中方法的拦截：
 [registrar addApplicationDelegate:instance];

需要在应用的AppDelegate中注意

一、如果应用的AppDelegate是继承自FlutterAppDelegate:
@interface AppDelegate : FlutterAppDelegate

@implementation LoginPlugin

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {

FlutterMethodChannel* channel = [FlutterMethodChannel

methodChannelWithName:@"login_plugin"

binaryMessenger:[registrar messenger]];

LoginPlugin* instance = [[LoginPlugin alloc] init];

//注册Appdelegate的回调。

[registrar addApplicationDelegate:instance];

[registrar addMethodCallDelegate:instance channel:channel];

}

 

 

则需要注意：
1、如果在AppDelegate中增加了AppDelegate中回调的方法。

如果回调方法没有返回值，不需要加调用supper方法的代码。

如果在AppDelegate中没有实现对应的方法，也是不影响Plugin中注册的回调方法的调用的。

     如果此回调方法有返回值，则需要在增加的方法中要调用supper方法，
     如下：

- (BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey,id> *)launchOptions {
    
    [super application:application willFinishLaunchingWithOptions:launchOptions];
    
    return YES;
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey,id> *)launchOptions {
   
    [super application:application didFinishLaunchingWithOptions:launchOptions];
    
    return YES;
}

二、如果AppDelegate没有继承自FlutterAppDelegate,
     则在AppDelegate中的每一个回调方法中，都要加入对
     _lifeCycleDelegate 的调用。

参考：
https://flutter.cn/docs/development/add-to-app/ios/add-flutter-screen?tab=engine-objective-c-tab

例如：
content_copy
@import Flutter;
@import UIKit;
@import FlutterPluginRegistrant;

@interface AppDelegate : UIResponder <UIApplicationDelegate, FlutterAppLifeCycleProvider>
@property (strong, nonatomic) UIWindow *window;
@property (nonatomic,strong) FlutterEngine *flutterEngine;
@end
在具体实现中，应该最大化地委托给 FlutterPluginAppLifeCycleDelegate：

content_copy
@interface AppDelegate ()
@property (nonatomic, strong) FlutterPluginAppLifeCycleDelegate* lifeCycleDelegate;
@end

@implementation AppDelegate

- (instancetype)init {
    if (self = [super init]) {
        _lifeCycleDelegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
    }
    return self;
}

- (BOOL)application:(UIApplication*)application
didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey, id>*))launchOptions {
    self.flutterEngine = [[FlutterEngine alloc] initWithName:@"io.flutter" project:nil];
    [self.flutterEngine runWithEntrypoint:nil];
    [GeneratedPluginRegistrant registerWithRegistry:self.flutterEngine];
    return [_lifeCycleDelegate application:application didFinishLaunchingWithOptions:launchOptions];
}