控制进度条的移动，我采用的是NSTimer，添加了一个定时器，并且在不需要它的地方都做了相应的移除操作。
这里开发的时候，遇到了一个问题是，我拖动滑块的时候，发现歌曲播放的进度是不正确的。代码中可以看到：
//得到挪动距离
CGPoint point = [sender translationInView:sender.view];
//将translation清空，免得重复叠加
[sender setTranslation:CGPointZero inView:sender.view];
在使用translation的时候，一定要记住，每次处理过后，一定要将translation清空，以免它不断叠加。
我使用的是ZYLrcView来展示歌词界面的，需要注意的是，它继承自UIImageView，所以要将userInteractionEnabled属性设置为Yes。
代码：
#import <UIKit/UIKit.h>
@interface ZYLrcView : UIImageView
@property (nonatomic, assign) NSTimeInterval currentTime;
@property (nonatomic, copy) NSString *fileName;
@end
#import "ZYLrcView.h"
#import "ZYLrcLine.h"
#import "ZYLrcCell.h"
#import "UIView+AutoLayout.h"
@interface ZYLrcView () <UITableViewDataSource, UITableViewDelegate>
@property (nonatomic, weak) UITableView *tableView;
@property (nonatomic, strong) NSMutableArray *lrcLines;
/**
* 记录当前显示歌词在数组里面的index
*/
@property (nonatomic, assign) int currentIndex;
@end
@implementation ZYLrcView
#pragma mark ----settergeter方法
- (NSMutableArray *)lrcLines
{
if (_lrcLines == nil) {
_lrcLines = [ZYLrcLine lrcLinesWithFileName:self.fileName];
}
return _lrcLines;
}
- (void)setFileName:(NSString *)fileName
{
if ([_fileName isEqualToString:fileName]) {
return;
}
_fileName = [fileName copy];
[_lrcLines removeAllObjects];
_lrcLines = nil;
[self.tableView reloadData];
}
- (void)setCurrentTime:(NSTimeInterval)currentTime
{
if (_currentTime > currentTime) {
self.currentIndex = 0;
}
_currentTime = currentTime;
int minute = currentTime / 60;
int second = (int)currentTime % 60;
int msecond = (currentTime - (int)currentTime) * 100;
NSString *currentTimeStr = [NSString stringWithFormat:@"%02d:%02d.%02d", minute, second, msecond];
for (int i = self.currentIndex; i < self.lrcLines.count; i++) {
ZYLrcLine *currentLine = self.lrcLines[i];
NSString *currentLineTime = currentLine.time;
NSString *nextLineTime = nil;
if (i + 1 < self.lrcLines.count) {
ZYLrcLine *nextLine = self.lrcLines[i + 1];
nextLineTime = nextLine.time;
}
if (([currentTimeStr compare:currentLineTime] != NSOrderedAscending) && ([currentTimeStr compare:nextLineTime] == NSOrderedAscending) && (self.currentIndex != i)) {
NSArray *reloadLines = @[
[NSIndexPath indexPathForItem:self.currentIndex inSection:0],
[NSIndexPath indexPathForItem:i inSection:0]
];
self.currentIndex = i;
[self.tableView reloadRowsAtIndexPaths:reloadLines withRowAnimation:UITableViewRowAnimationNone];
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForItem:self.currentIndex inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
}
}
#pragma mark ----初始化方法
- (instancetype)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
[self commitInit];
}
return self;
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder
{
if (self = [super initWithCoder:aDecoder]) {
[self commitInit];
}
return self;
}
- (void)commitInit
{
self.userInteractionEnabled = YES;
self.image = [UIImage imageNamed:@"28131977_1383101943208"];
self.contentMode = UIViewContentModeScaleToFill;
self.clipsToBounds = YES;
UITableView *tableView = [[UITableView alloc] init];
tableView.delegate = self;
tableView.dataSource = self;
tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
tableView.backgroundColor = [UIColor clearColor];
self.tableView = tableView;
[self addSubview:tableView];
[self.tableView autoPinEdgesToSuperviewEdgesWithInsets:UIEdgeInsetsMake(0, 0, 0, 0)];
}
#pragma mark ----UITableViewDataSource
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.lrcLines.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
ZYLrcCell *cell = [ZYLrcCell lrcCellWithTableView:tableView];
cell.lrcLine = self.lrcLines[indexPath.row];
if (indexPath.row == self.currentIndex) {
cell.textLabel.font = [UIFont boldSystemFontOfSize:16];
}
else{
cell.textLabel.font = [UIFont systemFontOfSize:13];
}
return cell;
}
- (void)layoutSubviews
{
[super layoutSubviews];
// NSLog(@"++++++++++%@",NSStringFromCGRect(self.tableView.frame));
self.tableView.contentInset = UIEdgeInsetsMake(self.frame.size.height / 2, 0, self.frame.size.height / 2, 0);
}
@end
