Use MusicBrainz in iOS（三）查詢專輯的完整資訊

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本文討論下通過專輯名擷取專輯的完整資訊。包含歌曲列表。藝術家列表，發行時間和地區等。

因為是通過專輯名搜尋專輯資訊。所以搜尋出來的結果可能較多，比如一個“Violin Concertos”就可能包括多個搜尋結果，而本文僅僅是顯示專輯的完整資訊，並不進行進一步的匹配工作，因此以第一個搜尋結果為例。

代碼例如以下：

#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:@"錯誤：%@", [error localizedDescription]];        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"警告"                                                            message:message                                                           delegate:nil                                                  cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];        [alertView show];    };}- (void)alertWithMessage:(NSString *)message {    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"警告" message:message delegate:nil cancelButtonTitle:@"確定" 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];                // 專輯的mbid        _resultController.mbid = (release.Id) ? release.Id : UnknownString;        if (!release.Id) {            [self alertWithMessage:@"搜尋失敗"];            return;        }                // 專輯名        _resultController.title = (release.Title) ? release.Title : UnknownString;                // 專輯狀態        _resultController.status = (release.Status) ? release.Status : UnknownString;                // 專輯音質        _resultController.quality = (release.Quality) ? release.Quality : UnknownString;                MBTextRepresentation *textRepresentation = release.TextRepresentation;                // 專輯語言        _resultController.language = (textRepresentation.Language) ? textRepresentation.Language : UnknownString;                // 專輯劇本語言        _resultController.script = (textRepresentation.Script) ? textRepresentation.Script : UnknownString;                MBArtistCredit *artistCredit = release.ArtistCredit;        NSUInteger nameCount = (artistCredit.elementCount) ? artistCredit.elementCount : UnknownInteger;                // 專輯藝術家列表        _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(@"發行組織類型 = %@", group.Type);        NSLog(@"發行組織名稱 = %@", group.Title);                // 專輯發行日期        _resultController.date = (release.Date) ? release.Date : UnknownString;                // 專輯發行國家        _resultController.country = (release.Country) ? release.Country : UnknownString;                NSLog(@"專輯條碼 = %@", release.Barcode);        NSLog(@"Asin 標準識別碼，來自卓越亞馬遜 = %@", release.Asin);                MBList *mediumList = release.MediumList;        MBMedium *medium = [mediumList elementAtIndex:1];                // 專輯發行形式        _resultController.format = medium.Format;                NSLog(@"專輯中的音樂個數 = %d", medium.TrackList.Count.integerValue);                // 用一個列表顯示出專輯的具體資訊        [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:@"搜尋失敗"];        }    };        [conn enqueueRequest:req onSuccess:successBlock onFailure:self.failureBlock];}@end

其實，這和Use MusicBrainz in iOS（二）中的搜尋方法是一樣的。僅僅是搜尋的類型是MBEntityRelease。在搜尋並擷取到列表中的第一個結果後，我們選取其mbid進行進一步的查詢，由於僅僅有通過mbid的查詢才幹尋找到該專輯中包括什麼歌曲等資訊。

在查詢成功後。用一個表格來載入這些資料。ResultViewController類代碼例如以下：

#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 @"音樂列表";        case 1:            return @"藝術家";        case 2:            return @"基本資料";        case 3:            return @"附加資訊";        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:@"發行日期：%@", self.date];                break;            case 1:                text = [NSString stringWithFormat:@"發行地區：%@", self.country];                break;            case 2:                text = [NSString stringWithFormat:@"發行形式：%@", self.format];                break;            case 3:                text = [NSString stringWithFormat:@"語言：%@", 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:@"品質：%@", self.quality];                break;            case 1:                text = [NSString stringWithFormat:@"狀態：%@", self.status];                break;            default:                break;        }        cell.textLabel.text = text;    }        return cell;}@end

執行結果例如以下：

程式可能會繼續改動，看看明天有什麼進一步的需求提出來吧。

Use MusicBrainz in iOS（三）查詢專輯的完整資訊