1.使用第三方框架sdWebImage 下载的图片,要计算出他的大小,使用
#import <SDImageCache.h>
NSUInteger cacheSize = [[SDImageCache sharedImageCache]getSize];
获取文件夹缓存原理:
1.获取文件夹路径
2.遍历子文件,拼接全文件名
3.通过文件管理类获取文件信息 dict.fileSize
-(unsigned long long)getFileSize:(NSString *)directoryPath
{
//1.获取缓存文件夹
NSString * cachePath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
//2.拼接文件夹路径
NSString * filePath = [cachePath stringByAppendingPathComponent:directoryPath];
//3.判断是否文件夹 是 遍历子文件夹,算出文件总大小; 否 算出当前文件夹
NSFileManager * mgr = [NSFileManager defaultManager];
unsigned long long cacheSize = 0;
BOOL isDirectory = NO;
BOOL isExist= [mgr fileExistsAtPath:filePath isDirectory:&isDirectory];
if ( ! isExist)
{
NSException * exception = [NSException exceptionWithName:@"非法路径" reason:@"路径不存在" userInfo:nil];
[exception raise];
}
if (isDirectory) {
NSDirectoryEnumerator * enumerator = [mgr enumeratorAtPath:filePath];
for (NSString * subPath in enumerator) {
NSString * fullPath = [filePath stringByAppendingPathComponent:subPath];
NSDictionary * dict = [mgr attributesOfItemAtPath:fullPath error:nil];
cacheSize += dict.fileSize;
}
}
else {
cacheSize = [mgr attributesOfItemAtPath:filePath error:nil].fileSize;
}
return cacheSize;
}
处理不同cell共存,将清除缓存的cell抽成自定义cell
static NSString * const LMClearCellID = @"LMClearCellID";
@implementation LMSettingController
- (void)viewDidLoad {
[super viewDidLoad];
[self.tableView registerClass:[LMClearCell class]forCellReuseIdentifier:LMClearCellID];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
return [tableView dequeueReusableCellWithIdentifier:LMClearCellID];
}
换算单位
-(NSString *) cacheStr
{
if (_cacheStr == nil) {
if (_cacheSize > pow(10, 9)) {
_cacheStr = [NSString stringWithFormat:@"清除缓存(%.2fGB)",_cacheSize / pow(10, 9)];
}
else if (_cacheSize > pow(10, 6)){
_cacheStr = [NSString stringWithFormat:@"清除缓存(%.2fMB)",_cacheSize / pow(10, 6)];
}
else if (_cacheSize > pow(10, 3)){
_cacheStr = [NSString stringWithFormat:@"清除缓存(%.2fKB)",_cacheSize / pow(10, 3)];
}
else
{
_cacheStr = [NSString stringWithFormat:@"清除缓存(%zdB)",_cacheSize];
}
}
return _cacheStr;
}
开启子线程计算大小
-(instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
if (self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
self.textLabel.text = @"正在计算大小...";
self.userInteractionEnabled = NO;
__weak typeof (self) weakSelf = self;
//开启子线程计算大小
dispatch_async(dispatch_get_global_queue(0, 0), ^{
sleep(5);
NSString * cachePath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
NSString * filePath = [cachePath stringByAppendingPathComponent:@"default"];
weakSelf.cacheSize = [LMFileCacheManger getFileSize:filePath];
if (weakSelf == nil) return ;
dispatch_async(dispatch_get_main_queue(), ^{
weakSelf.textLabel.text = weakSelf.cacheStr;
weakSelf.userInteractionEnabled = YES;
});
});
}
return self;
}
点击cell删除缓存
1.先删除SDWebImage的缓存,再删除自己的缓存
2.根据需要重新创建自己的文件夹
(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell * cell = [tableView cellForRowAtIndexPath:indexPath];
if ([cell isKindOfClass:[LMClearCell class]]) {
LMClearCell * clearCell = (LMClearCell *)cell;
[clearCell clearCache];
}
}
---
-(void)clearCache
{
//先删除SDWebImage的缓存
[[SDImageCache sharedImageCache] clearDiskOnCompletion:^{
NSString * path = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
NSLog(@"%@",path);
NSString* fullpath = [path stringByAppendingPathComponent:@"custom"];
[LMFileCacheManger clearFileCache:fullpath]; //删除自己的文件夹
dispatch_async(dispatch_get_main_queue(),^{//回到主线程刷新UI
self.textLabel.text = @"清除缓存(0B)";
});
}];
}
---
+(void)clearFileCache:(NSString *)filePath
{
[SVProgressHUD showWithStatus:@"正在删除"];
[SVProgressHUD setDefaultMaskType:SVProgressHUDMaskTypeBlack];
NSFileManager * mgr = [NSFileManager defaultManager];
dispatch_async(dispatch_get_global_queue(0, 0), ^{
[mgr removeItemAtPath:filePath error:nil];
dispatch_async(dispatch_get_main_queue(), ^{
[SVProgressHUD showSuccessWithStatus:@"删除成功"];
});
});
}
用户体验细节
1.如果缓存文件非常大,那么应该开启子线程下载
2.当前正在计算过程中,cell不能被点击
3.当用户在计算缓存过程中,点击返回按钮,退出当前控制器,那么无需再回到主线程刷新UI
// 如果cell已经销毁了, 就直接返回
if (weakSelf == nil) return;
遇到的bug
1.设置cell默认的文字(如果设置文字之前userInteractionEnabled=NO, 那么文字会自动变成浅灰色)
self.textLabel.text = @"清除缓存(正在计算缓存大小...)";
self.userInteractionEnabled = NO;
2.block 强引用(block会对外部对象进行强引用,直到block执行完才会销毁)
__weak typeof(self) weakSelf = self; //__weak修饰
相关博客:
http://www.jianshu.com/p/76614766b2ea
http://www.cnblogs.com/pengyingh/articles/2350345.html
