Use MusicBrainz in iOS（三）查询专辑的完整信息
浏览数：29 /
时间：2015年06月11日
本文讨论下通过专辑名获取专辑的完整信息，包括歌曲列表，艺术家列表，发行时间和地区等。
由于是通过专辑名搜索专辑信息，所以搜索出来的结果可能较多，例如一个“Violin Concertos”就可能包含多个搜索结果，而本文只是显示专辑的完整信息，并不进行进一步的匹配工作，因此以第一个搜索结果为例。
代码如下：
#import "AlbumViewController.h"
#import "MB.h"
#import "ResultViewController.h"
#define UnknownString @"未知"
#define UnknownInteger 0
@interface AlbumViewController ()
@property (strong, nonatomic) ResultViewController *resultController;
@property (copy, nonatomic) RequestFailureBlock failureBlock;
@end
@implementation AlbumViewController
@synthesize resultController = _resultController;
- (void)viewDidLoad
{
[super viewDidLoad];
self.resultController = [[UIStoryboard storyboardWithName:@"Main" bundle:nil] instantiateViewControllerWithIdentifier:@"ResultViewController"];
self.failureBlock = ^(MBRequest *request, NSError *error, NSData *data) {
NSString *message = [NSString stringWithFormat:@"错误：%@", [error localizedDescription]];
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"警告"
message:message
delegate:nil
cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
[alertView show];
};
}
- (void)alertWithMessage:(NSString *)message {
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"警告" message:message delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
[alertView show];
}
- (IBAction)search:(id)sender {
MBConnection *conn = [MBConnection connection];
RequestSuccessBlock successBlock = ^(MBRequest *request, MBMetadata *metadata) {
MBList *list = metadata.ReleaseList;
MBRelease *release = [list elementAtIndex:0];
// 专辑的mbid
_resultController.mbid = (release.Id) ? release.Id : UnknownString;
if (!release.Id) {
[self alertWithMessage:@"搜索失败"];
return;
}
// 专辑名
_resultController.title = (release.Title) ? release.Title : UnknownString;
// 专辑状态
_resultController.status = (release.Status) ? release.Status : UnknownString;
// 专辑音质
_resultController.quality = (release.Quality) ? release.Quality : UnknownString;
MBTextRepresentation *textRepresentation = release.TextRepresentation;
// 专辑语言
_resultController.language = (textRepresentation.Language) ? textRepresentation.Language : UnknownString;
// 专辑剧本语言
_resultController.script = (textRepresentation.Script) ? textRepresentation.Script : UnknownString;
MBArtistCredit *artistCredit = release.ArtistCredit;
NSUInteger nameCount = (artistCredit.elementCount) ? artistCredit.elementCount : UnknownInteger;
// 专辑艺术家列表
_resultController.artists = [NSMutableArray array];
for (int i = 0; i < nameCount; i++) {
MBNameCredit *nameCredit = [artistCredit elementAtIndex:i];
[_resultController.artists addObject:nameCredit.Artist.Name];
}
MBReleaseGroup *group = release.ReleaseGroup;
NSLog(@"发行组织类型 = %@", group.Type);
NSLog(@"发行组织名称 = %@", group.Title);
// 专辑发行日期
_resultController.date = (release.Date) ? release.Date : UnknownString;
// 专辑发行国家
_resultController.country = (release.Country) ? release.Country : UnknownString;
NSLog(@"专辑条形码 = %@", release.Barcode);
NSLog(@"Asin 标准识别码，来自卓越亚马逊 = %@", release.Asin);
MBList *mediumList = release.MediumList;
MBMedium *medium = [mediumList elementAtIndex:1];
// 专辑发行形式
_resultController.format = medium.Format;
NSLog(@"专辑中的音乐个数 = %d", medium.TrackList.Count.integerValue);
// 用一个列表显示出专辑的详细信息
[self showAllData:release.Id];
};
MBRequest *req = [MBRequest searchForEntity:MBEntityRelease
query:@"Violin Concertos"
// query:@"不想放手"
limit:[NSNumber numberWithInteger:10]
offset:[NSNumber numberWithInteger:0]];
[conn enqueueRequest:req onSuccess:successBlock onFailure:self.failureBlock];
}
- (void)showAllData:(NSString *)mbid {
MBConnection *conn = [MBConnection connection];
MBRequest *req = [MBRequest lookupWithEntity:MBEntityRelease
mbid:mbid
incParameters:(MBIncParameterRecordings | MBIncParameterRecordingRels)];
void (^successBlock)(MBRequest *, MBMetadata *) = ^(MBRequest *request, MBMetadata *metadata) {
MBRelease *release = metadata.Release;
if (release) {
_resultController.tracks = [NSMutableArray array];
MBList *mediumList = release.MediumList;
MBMedium *medium = [mediumList elementAtIndex:0];
MBList *trackList = medium.TrackList;
for (MBTrack *track in trackList) {
[_resultController.tracks addObject:track.Recording.Title];
}
[self.navigationController pushViewController:_resultController animated:YES];
NSLog(@"Success");
}
else {
[self alertWithMessage:@"搜索失败"];
}
};
[conn enqueueRequest:req onSuccess:successBlock onFailure:self.failureBlock];
}
@end事实上，这和Use MusicBrainz in iOS（二）中的搜索方法是一样的，只是搜索的类型是MBEntityRelease。在搜索并获取到列表中的第一个结果后，我们选取其mbid进行进一步的查询，因为只有通过mbid的查询才能查找到该专辑中包含什么歌曲等信息。
在查询成功后，用一个表格来加载这些数据。ResultViewController类代码如下：
#import <UIKit/UIKit.h> @interface ResultViewController : UITableViewController @property (strong, nonatomic) NSMutableArray *tracks; @property (strong, nonatomic) NSMutableArray *artists; @property (copy, nonatomic) NSString *title; @property (copy, nonatomic) NSString *mbid; @property (copy, nonatomic) NSString *date; @property (copy, nonatomic) NSString *country; @property (copy, nonatomic) NSString *format; @property (copy, nonatomic) NSString *language; @property (copy, nonatomic) NSString *script; @property (copy, nonatomic) NSString *quality; @property (copy, nonatomic) NSString *status; @end
#import "ResultViewController.h"
@interface ResultViewController ()
@end
@implementation ResultViewController
- (void)viewDidLoad {
[super viewDidLoad];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.navigationItem.title = self.title;
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 4;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
switch (section) {
case 0:
return [self.tracks count];
case 1:
return [self.artists count];
case 2:
return 5;
case 3:
return 2;
default:
return 0;
}
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
switch (section) {
case 0:
return @"音乐列表";
case 1:
return @"艺术家";
case 2:
return @"基本信息";
case 3:
return @"附加信息";
default:
return @"";
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CellIdentifier" forIndexPath:indexPath];
if (indexPath.section == 0) {
cell.textLabel.text = self.tracks[indexPath.row];
}
else if (indexPath.section == 1) {
cell.textLabel.text = self.artists[indexPath.row];
}
else if (indexPath.section == 2) {
NSString *text;
switch (indexPath.row) {
case 0:
text = [NSString stringWithFormat:@"发行日期：%@", self.date];
break;
case 1:
text = [NSString stringWithFormat:@"发行地区：%@", self.country];
break;
case 2:
text = [NSString stringWithFormat:@"发行形式：%@", self.format];
break;
case 3:
text = [NSString stringWithFormat:@"语言：%@", self.language];
break;
case 4:
text = [NSString stringWithFormat:@"Script：%@", self.script];
break;
default:
break;
}
cell.textLabel.text = text;
}
else if (indexPath.section == 3) {
NSString *text;
switch (indexPath.row) {
case 0:
text = [NSString stringWithFormat:@"品质：%@", self.quality];
break;
case 1:
text = [NSString stringWithFormat:@"状态：%@", self.status];
break;
default:
break;
}
cell.textLabel.text = text;
}
return cell;
}
@end运行结果如下：
程序可能会继续修改，看看明天有什么进一步的需求提出来吧。
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