ios-檔案預覽-QLPreViewController
最近在做的專案中有相關pdf檔案預覽的功能,所以瞭解了一下相關的資料。基本上網上給出來的方法有兩種,分別是用UIWebVie和CGContextDrawPDFPage,可以點選檢視,但是本文所要講的是另外一種方式-----使用QLPreViewController進行預覽,QLPreViewController不僅支援PDF,還支援其他多種檔案的預覽,可謂功能強大。
先看下官方文件的說法:
A displayed preview includes a title taken from the last path component of the item URL. You can override this by implementing a previewItemTitle
accessor
for the preview item.
A Quick Look preview controller can display previews for the following items:
-
iWork documents
-
Microsoft Office documents (Office ‘97 and newer)
-
Rich Text Format (RTF) documents
-
PDF files
-
Images
-
Text files whose uniform type identifier (UTI) conforms to the
public.text
-
Comma-separated value (csv) files
使用方式:
1.首先新建一個QLPreviewController物件preview;
2.遵循協議QLPreviewControllerDataSource,設定代理;
3.實現協議方法:返回文件數量方法- (NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)controller;
返回URL的方法 - (id <QLPreviewItem>)previewController:(QLPreviewController *)controller previewItemAtIndex:(NSInteger)index;
4.模態或push出QLPreviewController的物件preview。
關鍵程式碼:
#pragma mark -QLPreviewControllerDataSource
- (NSInteger)numberOfPreviewItemsInPreviewController:(QLPreviewController *)controller {
return 1;
}
- (id<QLPreviewItem>)previewController:(QLPreviewController *)controller previewItemAtIndex:(NSInteger)index {
NSString *filePath = [[HKClassRoomManager sharedInstance] getFilePath:self.classFile];
NSAssert(filePath, @"preview nil item");
NSFileManager* fileManager = [NSFileManager defaultManager];
NSError* error = nil;
if ([fileManager fileExistsAtPath:filePath]) {
NSDictionary* fileInfo = [fileManager attributesOfItemAtPath:filePath
error:&error];
NSInteger fileSize = [[fileInfo objectForKey:NSFileSize] integerValue];
if (fileSize >= 1024 * 1024 * 10) {
[NSObject showHudTipStr:@"檔案較大,載入可能需要一段時間,請等待...."];
}
}
NSData *fileData = [NSData dataWithContentsOfFile:filePath];
//判斷是UNICODE編碼
NSString *isUNICODE = [[NSString alloc] initWithData:fileData encoding:NSUTF8StringEncoding];
//還是ANSI編碼
NSString *isANSI = [[NSString alloc] initWithData:fileData encoding:-2147482062];
if (isUNICODE) {
NSString *retStr = [[NSString alloc]initWithCString:[isUNICODE UTF8String] encoding:NSUTF8StringEncoding];
NSData *data = [retStr dataUsingEncoding:NSUTF16StringEncoding];
NSError *error = nil;
[data writeToFile:filePath options:NSDataWritingAtomic error:&error];
}
else if(isANSI){
NSData *data = [isANSI dataUsingEncoding:NSUTF16StringEncoding];
NSError *error = nil;
[data writeToFile:filePath options:NSDataWritingAtomic error:&error];
}
NSURL *fileURL = [NSURL fileURLWithPath:filePath];
return fileURL;
}