常用的APP間通訊場景是支付和分享。接入支付寶等支付場景時需要跳轉到支付寶APP，完成支付后再將支付結果返回原來的APP，這樣就涉及APP間傳值。

新建App1和App2兩個應用，如果我想從App1調起App2，那么我需要添加App2的URL Scheme，不同于其他手機APPs的值，用來在App1發(fā)起openUrl方法時找到手機里的App2應用。

設置App2的URL Scheme為AppTwoScheme

App1想要調起App2時只需要通過如下方法即可

NSURL *url = [NSURL URLWithString: [NSString stringWithFormat: @"AppTwoScheme://com.zy.app1/subpath?para=%i&from=%@", 1, @"app1"]];
if ([[UIApplication sharedApplication] canOpenURL: url]) {
    NSLog(@"canOpenUrl");
    if (@available(iOS 10, *)) {
        NSDictionary *options = @{UIApplicationOpenURLOptionsSourceApplicationKey : @YES};
        [[UIApplication sharedApplication] openURL: url options: options completionHandler: nil];
    }else{
        [[UIApplication sharedApplication] openURL: url];
    }
}

從iOS 10開始，還需要在App1中添加白名單LSApplicationQueriesSchemes數組

在App2的AppDelegate代理方法中接收傳入的值，如果使用SceneDelegate類，則在-(void)scene:(UIScene *)scene openURLContexts:(NSSet<UIOpenURLContext *> *)URLContexts代理方法中接收。

-(BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options
{
    UIAlertController *alertVC = [UIAlertController alertControllerWithTitle: @"提示" message: @"收到一條從APP1傳來的簡訊" preferredStyle: UIAlertControllerStyleAlert];
    [self.window.rootViewController presentViewController: alertVC animated: YES completion: nil];
    NSLog(@"absoulteString: %@", url.absoluteString);
    NSLog(@"scheme: %@", url.scheme);
    NSLog(@"host: %@", url.host);
    NSLog(@"path: %@", url.path);
    NSLog(@"query: %@", url.query);
    NSLog(@"Url參數: %@", [self getURLParameters: url.absoluteString]);
    if ([url.host isEqualToString: @"com.zy.app1"]) {
        //從app1跳轉過來
    }
    return YES;
}

scheme、host和query等結果如下：

若需要將App2中的處理結果返回給App1，同樣的操作：設置App1的URL Scheme為AppOneScheme，添加App2的白名單為AppOneScheme，給App2一個觸發(fā)事件調用

UIAlertController *alertVC = [UIAlertController alertControllerWithTitle: @"提示" message: @"收到一條從APP1傳來的簡訊" preferredStyle: UIAlertControllerStyleAlert];
[alertVC addAction: [UIAlertAction actionWithTitle: @"確定" style: UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        NSURL *oneUrl = [NSURL URLWithString: [NSString stringWithFormat: @"AppOneScheme://com.zy.app2?result=1"]];
        if (@available(iOS 10, *)) {
            [[UIApplication sharedApplication] openURL: oneUrl options: @{} completionHandler: nil];
        }else{
            [[UIApplication sharedApplication] openURL: oneUrl];
        }
 }]];
 [self.window.rootViewController presentViewController: alertVC animated: YES completion: nil];

App1接收到的返回值為

-(void)scene:(UIScene *)scene openURLContexts:(NSSet<UIOpenURLContext *> *)URLContexts
{
    if (URLContexts.count > 0) {
        NSEnumerator *enumerator = [URLContexts objectEnumerator];
        UIOpenURLContext *urlContext = [enumerator nextObject];
        NSURL *url = urlContext.URL;
        NSLog(@"absoulteString: %@", url.absoluteString);
        NSLog(@"scheme: %@", url.scheme);
        NSLog(@"host: %@", url.host);
        NSLog(@"path: %@", url.path);
        NSLog(@"query: %@", url.query);
        NSLog(@"Url參數: %@", [self getURLParameters: url.absoluteString]);
        if ([url.host isEqualToString: @"com.zy.app2"]) {
            //從app2返回的數據
        }
    }
}

如此，即完成了一組App間的傳值。

但要注意，如果從左上角的返回按鈕回到App1則無法將結果返回，因為沒有調用openURL吧。