小程序打开app分两种情况：

app直接打开微信小程序之后的返回app

WXLaunchMiniProgramReq *launchMiniProgramReq = [WXLaunchMiniProgramReq object];launchMiniProgramReq.userName = userName;launchMiniProgramReq.path =path;launchMiniProgramReq.miniProgramType = miniProgramType;[WXApi sendReq:launchMiniProgramReq];复制代码

这种情况下，在微信小程序点击打开app的时候走的函数是:

- (void)onResp:(BaseResp *)resp{    if ([resp isKindOfClass:[WXLaunchMiniProgramResp class]]) {        NSString *errMsg = [NSString stringWithFormat:@"errorcode:%@",((WXLaunchMiniProgramResp*)resp).extMsg];        NSLog(@"errcode:%@",errMsg);    }}复制代码

app分享到微信聊天，然后在聊天里面打开小程序，再跳转回app

WXMiniProgramObject *object = [WXMiniProgramObject object];object.webpageUrl = urlobject.userName = username;object.hdImageData = dataobject.path = pathWXMediaMessage *message = [WXMediaMessage message];message.title = title;message.description = descriptionStr;message.thumbData = nil;message.mediaObject = object;SendMessageToWXReq *req = [[SendMessageToWXReq alloc] init];req.bText = NO;req.message = message;req.scene = WXSceneSession;  //目前只支持会话[WXApi sendReq:req];复制代码

这种情况下打开app传参走的是

- (void)onReq:(BaseReq *)req{    NSLog(@"req is %@",req);    if ([req isKindOfClass:[LaunchFromWXReq class]]) {        LaunchFromWXReq *wxReq = (LaunchFromWXReq*)req;        WXMediaMessage *message =  wxReq.message;        NSString *messageExt = message.messageExt;        NSLog(@"ext message is %@",messageExt);    }}复制代码

通常我们走的是第二种方式，这里很坑，微信文档也没有写详细。