ios - 将数据插入属于自定义对象的 NSMutableArray

Question

我有两个自定义对象:Movie 和 MovieTheater。在 MovieTheater 中，我有一个 NSMutableArray，我需要用它来添加电影。这是我的代码:

// theater 1
    MovieTheater* tempTh1 = [[MovieTheater alloc]init];
    Movie* tempMv1 = [[Movie alloc]init];

    if (tempTh1 != nil) {

        // set up a theather
        tempTh1.theaterName = @"Regal";
        tempTh1.theaterLocation = @"35335 Riverside,CA 92506";
        tempTh1.theaterImage = [UIImage imageNamed:@"theatremain.ashx.jpg"];

        // set up movie 1 ------------------------------------------------------------------


        if (tempMv1 != nil) {

            tempMv1.movieName = @"The Zero Theorem";
            tempMv1.movieTime = @"SAT 18:30";
            tempMv1.movieImage = [UIImage imageNamed:@"zerotheorem.jpg"];
            tempMv1.movieTrailer = [NSURL URLWithString:@"http://youtu.be/XpsJPOMfGSo"];

            // add movie to theater array
            [tempTh1.theaterMovies insertObject:tempMv1 atIndex:0];
        }



        // set up movie 2 ------------------------------------------------------------------
        Movie* tempMv2 = [[Movie alloc]init];

        if (tempMv2 != nil) {

            tempMv2.movieName = @"Welcome to the Jungle";
            tempMv2.movieTime = @"TH 16:30";
            tempMv2.movieImage = [UIImage imageNamed:@"welcometothejungle.jpg"];
            tempMv2.movieTrailer = [NSURL URLWithString:@"http://youtu.be/kRzSImxqQtA"];
        }

        // add movie to theater array
        [tempTh1.theaterMovies insertObject:tempMv2 atIndex:1];

        // set up movie 3 ------------------------------------------------------------------
        Movie* tempMv3 = [[Movie alloc]init];

        if (tempMv3 != nil) {

            tempMv3.movieName = @"The Bag Man";
            tempMv3.movieTime = @"TUE 15:30";
            tempMv3.movieImage = [UIImage imageNamed:@"bagman.jpg"];
            tempMv3.movieTrailer = [NSURL URLWithString:@"http://youtu.be/mKBLfwVEKP8"];
        }

        // add movie to theater array
        [tempTh1.theaterMovies insertObject:tempMv3 atIndex:2];

        // set up movie 4 ------------------------------------------------------------------
        Movie* tempMv4 = [[Movie alloc]init];

        if (tempMv4 != nil) {

            tempMv4.movieName = @"Better Living Through Chemistry";
            tempMv4.movieTime = @"MO 16:45";
            tempMv4.movieImage = [UIImage imageNamed:@"betterlivingthroughchemistry.jpg"];
            tempMv4.movieTrailer = [NSURL URLWithString:@"http://youtu.be/qxHPqHIl11w"];
        }

        // add movie to theater array
        [tempTh1.theaterMovies insertObject:tempMv4 atIndex:3];

        // set up movie 5 ------------------------------------------------------------------
        Movie* tempMv5 = [[Movie alloc]init];

        if (tempMv5 != nil) {

            tempMv5.movieName = @"Blood Ties";
            tempMv5.movieTime = @"FR 19:00";
            tempMv5.movieImage = [UIImage imageNamed:@"bloodties.jpg"];
            tempMv5.movieTrailer = [NSURL URLWithString:@"http://youtu.be/DI86othXjho"];
        }

        // add movie to theater array
        [tempTh1.theaterMovies insertObject:tempMv5 atIndex:4];


        // add the theater to the global array
        [cinemas insertObject:tempTh1 atIndex:0];

        NSLog(@"%@", tempTh1.theaterMovies);
    }

我遇到的问题是 [tempTh1.theaterMovies insertObject:tempMv1 atIndex:0];不添加任何东西。 NSLog 显示数组 theaterMovies nil。我究竟做错了什么？

Answer 1

在 MovieTheater 的 init 方法中初始化 tempTh1.theaterMovies，或者在您开始添加具有空 NSMutableArray 的对象之前，例如

tempTh1.theaterMovies = [NSMutableArray array];