edu-saas-ios/MusicGradeExam/MusicGradeExam/UI/ExamLibrary/Controller/OpenFileViewController.m

//
//  OpenFileViewController.m
//  MusicGradeExam
//
//  Created by Kyle on 2020/7/21.
//  Copyright © 2020 DayaMusic. All rights reserved.
//

#import "OpenFileViewController.h"
#import <QuickLook/QuickLook.h>

@interface OpenFileViewController ()<QLPreviewControllerDataSource, QLPreviewControllerDelegate>

@property (nonatomic, strong) QLPreviewController *previewCtrl;


@property (nonatomic, strong) NSMutableArray *fileArray;


@end

@implementation OpenFileViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    [self allocTitle:[NSString returnNoNullStringWithString:self.fileName]];
    [self addChildViewController:self.previewCtrl];
}


- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [self requestFileSource];
    [self.previewCtrl addObserver:self forKeyPath:@"currentPreviewItemIndex" options:NSKeyValueObservingOptionNew context:nil];
}

- (void)requestFileSource { // 如果缓存中有，不会再次下载
    
    [MBProgressHUD ksShowHUDWithText:@"数据加载中......"];
    NSArray *urlArray = [self.urlString containsString:@","] ? [self.urlString componentsSeparatedByString:@","] : @[self.urlString];
    [KSRequestManager mutiDownloadFileRequest:urlArray progress:^(int64_t bytesRead, int64_t totalBytes) {
        
    } success:^(NSArray * _Nonnull dics) {
        [MBProgressHUD ksHideHUD];
        self.fileArray = [NSMutableArray arrayWithArray:dics];
        [self.view addSubview:self.previewCtrl.view];
        [self.previewCtrl refreshCurrentPreviewItem];
    } faliure:^(NSError * _Nonnull error) {
        [MBProgressHUD ksHideHUD];
    }];
}

#pragma mark ------ QLPreviewControllerDataSource
- (id<QLPreviewItem>)previewController:(QLPreviewController *)controller previewItemAtIndex:(NSInteger)index {
    return self.fileArray[index];
}

- (BOOL)previewController:(QLPreviewController *)controller shouldOpenURL:(NSURL *)url forPreviewItem:(id<QLPreviewItem>)item {
    return NO;
}
- (NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)previewController {
    return self.fileArray.count;
}

- (QLPreviewController *)previewCtrl {
    if (!_previewCtrl) {
        _previewCtrl = [[QLPreviewController alloc] init];
        _previewCtrl.view.frame = CGRectMake(0, 0, kScreenWidth, kScreenHeight - kNaviBarHeight - iPhoneXSafeBottomMargin);
        _previewCtrl.delegate = self;
        _previewCtrl.dataSource = self;
        _previewCtrl.currentPreviewItemIndex = 0;
        _previewCtrl.navigationController.navigationBar.userInteractionEnabled = NO;
    }
    return _previewCtrl;
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context {
    NSInteger currentIndex = [[change objectForKey:@"new"] integerValue];
    self.navigationController.interactivePopGestureRecognizer.enabled = (currentIndex == 0);
    [self rightButtonTitle:[NSString stringWithFormat:@"%zd/%zd", (currentIndex+1),self.fileArray.count]];
}


- (void)dealloc {
    [self.previewCtrl removeObserver:self forKeyPath:@"currentPreviewItemIndex"];
}
/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end