简单实现判断本地是否存在已经下载视频

前言：最近笔者在做视频播放器，所以，写的东西，都和这个有些关系，希望对大家有所帮助。废话不多说，进入主题。

1.首先播放页面需要写个属性接收本地的FileName，然后传递链接的时候做判断，这样第一步就完成了

NSURL *playURL;
    if (self.playName != nil) {
        playURL = [NSURL fileURLWithPath:self.playName];
    }else{
        playURL = [NSURL URLWithString:self.dailySelected.playUrl];
    }

2.关于传递的FileName，是一个放在数据库的全部不变量，所以我们必须为此建一个表，并且新建一个Model。如果不是不变量，会存在退出后，在点相同页面时，传值丢失问题

//下载按钮
    [self.playView.downloadButton addTarget:self action:@selector(downloadMovie) forControlEvents:(UIControlEventTouchUpInside)];

- (void)downloadMovie
{
    
    self.downloadPercent = [[ProgressView alloc] initWithURL:[NSURL URLWithString:self.dailySelected.playUrl] progressViewWithFrame:(CGRectMake(self.playView.downloadButton.frame.origin.x + 30, self.playView.downloadButton.frame.origin.y + self.navigationController.navigationBar.frame.size.height + 20 + 10, 60, 20)) font:[UIFont fontWithName:@"Georgia-BoldItalic" size:12.0] color:[UIColor whiteColor] timeout:5.0 alive:YES radius:0 delegate:self];
    [self.view addSubview:self.downloadPercent];
    self.playView.downloadButton.userInteractionEnabled = NO;
}

- (void)progressView:(ProgressView *)progressView didFinishedWithData:(NSData *)data suggestedWithFileName:(NSString *)fileName
{
    [UIView animateWithDuration:0.5 animations:^{
        self.downloadPercent.alpha = 0;
    }];
    [self.downloadPercent performSelector:@selector(removeFromSuperview) withObject:nil afterDelay:0.5];
    self.playView.downloadButton.tintColor = [UIColor redColor];
    self.playView.downloadButton.userInteractionEnabled = NO;
    [[OpenEyeDataBase shareSqliteManager]insertDownloadWithModel:self.dailySelected];
    [[NSNotificationCenter defaultCenter]postNotificationName:@"downloadComplete" object:nil];
    self.fileName = fileName;
    //将路径插入数据库
    [[OpenEyeDataBase shareSqliteManager] insertDownloadWithModel:self.dailySelected fileName:fileName];
    //NSLog(@"%@",self.fileName);
}

注：上面代码有个小封装，在我另一个文章中有源码

3.最后就是在进入页面时，有个判断，通过遍历数据库来判断

- (void)viewWillAppear:(BOOL)animated
{
    for (DailySelected *dailySelected in [[OpenEyeDataBase shareSqliteManager] selectDownloadAllModel]) {
        NSString *string = [NSString stringWithFormat:@"%@",self.dailySelected.ID];
        if (string == dailySelected.ID) {
            self.playView.downloadButton.tintColor = [UIColor redColor];
            self.playView.downloadButton.userInteractionEnabled = NO;
            for (FileModel *fileModel in [[OpenEyeDataBase shareSqliteManager] selectDownloadFileNameAllModel]) {
                if (string == fileModel.ID) {
                    self.fileName = fileModel.fileName;
                }
            }
        }
    }
}

这些操作后，就能实现了，如果不明白可以留言，小弟一定详细及及时解释