[英]iPhone app take a lot of memory while appending images and loading in uiwebview
我想顯示一個tiff文件,可以說25頁。 我必須通過滾動逐頁顯示tiff文件。 僅供參考,我不想使用來自github的NSTiffSplitter,我想下載下一頁,因為用戶向下滾動uiwebview的scrollview。 我正在下載第一頁字節(數組),將其轉換為.jpeg文件(image1.jpeg),並將其寫入文檔目錄,然后將下載的頁面加載到UIWebview中。 現在,當用戶在滾動視圖的末尾向下滑動時,我將tiff文件的第二頁下載為字節,將其轉換為.jpeg(image2.jpeg),將其保存到文檔目錄中,並附加第一頁(image1.jpeg),然后將附加的圖像加載到UIWebview。
可以說7頁,在8到10個應用上顯示內存警告和崩潰。 讓我也發布代碼。
我的想法是imageByCombiningImage正在消耗內存而不釋放內存。 需要專家咨詢。
-(void)saveAndDisplayFullImageiPad:(NSDictionary *)dicIn{
int pageNumber = [[dicIn objectForKey:@"SortNo"]intValue];//page number comes in web service response
self.currentFilePageCount = [[dicIn objectForKey:@"PagesCount"]intValue];
NSArray *arrayOfBytes = [dicIn objectForKey:@"FileBytes"];
if (arrayOfBytes != nil && [arrayOfBytes count] > 0) {
unsigned c = arrayOfBytes.count;
uint8_t *bytes = malloc(sizeof(*bytes) * c);
unsigned i;
for (i = 0; i < c; i++){
NSString *str = [arrayOfBytes objectAtIndex:i];
int byte = [str intValue];
bytes[i] = (uint8_t)byte;
}
NSData *data = [NSData dataWithBytes:(const void *)bytes length:sizeof(unsigned char)*c];
free(bytes);
NSString *fileNameCPath=[dicIn objectForKey:@"FilePath"];
NSString *fileNamePlusExtension = [[fileNameCPath componentsSeparatedByString:@"\\"] lastObject];
NSString *justFileName = [[fileNamePlusExtension componentsSeparatedByString:@"." ]firstObject];
self.standardTiffPageName = [justFileName stringByAppendingString:@"PageNumber"];
NSString *fileWithPageNum = [justFileName stringByAppendingString:[NSString stringWithFormat:@"PageNumber%d.jpeg",pageNumber]];
NSString *fileWithDirPath = [[[AppSettings sharedAppSettings]getDocumentDirectory] stringByAppendingPathComponent:fileWithPageNum];//document directory path appended
NSLog(@"filePathWritten = %@",fileWithDirPath);
[data writeToFile:fileWithDirPath atomically:YES];
self.tiffMainPageName = fileWithDirPath;
[self.tiffPagesNameArray addObject:fileWithDirPath];//just saving pages path names
if (pageNumber == 1) {
self.tiffMainPageName = fileWithDirPath;//tiffMainPageName has the appended images
}
if (pageNumber > 1) {
UIImage *img1 = [UIImage imageWithContentsOfFile:self.tiffMainPageName];
UIImage *img2 = [UIImage imageWithContentsOfFile:fileWithDirPath];
UIImage *finalImage = [self imageByCombiningImage:img1 withImage:img2];
NSData *dataFinalImage = UIImageJPEGRepresentation(finalImage, 0.5);
[dataFinalImage writeToFile:self.tiffMainPageName atomically:YES];
}
}
[self.webView1 loadRequest:[NSURLRequest requestWithURL:[NSURL fileURLWithPath:self.tiffMainPageName]]];
self.tiffPageDownloadComplete = YES;
}
- (UIImage*)imageByCombiningImage:(UIImage*)image1 withImage:(UIImage*)image2 {
CGSize size = CGSizeMake(image1.size.width, image1.size.height + image2.size.height);
UIGraphicsBeginImageContext(size);
[image1 drawInRect:CGRectMake(0,0,size.width, image1.size.height)];
[image2 drawInRect:CGRectMake(0,image1.size.height,size.width, image2.size.height)];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return finalImage;
}
我認為您只是在創建一個最終太大而無法容納到內存中的圖像。 而是通過附加上一頁的圖像來創建越來越大的圖像,可能只是您可以在上一頁的下方顯示下一頁的圖像。
對於Webview,您始終可以生成一個新的“ html頁面”,其中包含所需的圖像。 使用這樣的功能:
- (NSString*)htmlStringWithImagesOnPaths:(NSArray*)imagePaths {
NSString* html = @"<html><head><title></title></head><body>";
for(NSString* imagePath in imagePaths)
html = [html stringByAppendingString:[NSString stringWithFormat:@"<img src=\"%@\">", imagePath]];
return [html stringByAppendingString:@"</body></html>"];
}
然后執行以下操作,而不是[self.webView1 loadRequest:[NSURLRequest requestWithURL:[NSURL fileURLWithPath:self.tiffMainPageName]]]
:
NSString *documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES) objectAtIndex:0];
[webView loadHTMLString:[self htmlStringWithImagesOnPaths:self.imagePaths] baseURL:[NSURL fileURLWithPath: documentsDirectoryPath]];
在這種情況下,您應該在htmlStringWithImagesOnPaths:
方法(相對於documents目錄)的imagePaths
參數中提供一個相對路徑數組。
另一注-我不確定為什么在NSArray *arrayOfBytes = [dicIn objectForKey:@"FileBytes"];
您需要將此字節數組轉換為NSString
,然后再轉換回字節,然后將其保存到文件中。 為什么不立即將其保存到文件中(使用[arrayOfBytes writeToFile:fileWithDirPath atomically:YES])
?
祝好運
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