这里我正在生成UIViews的图像，为此我使用以下代码：
// ======================== Create PDF FROM Images ============================
- (void) drawBorder
{
CGContextRef currentContext = UIGraphicsGetCurrentContext();
UIColor *borderColor = [UIColor grayColor];
CGRect rectFrame = CGRectMake(kBorderInset, kBorderInset, pageSize.width-kBorderInset*2, pageSize.height-kBorderInset*2);
CGContextSetStrokeColorWithColor(currentContext, borderColor.CGColor);
CGContextSetLineWidth(currentContext, kBorderWidth);
CGContextStrokeRect(currentContext, rectFrame);
//CGContextRelease(currentContext);
}
- (void)drawPageNumber:(NSInteger)pageNumber
{
NSString* pageNumberString = [NSString stringWithFormat:@"Page %d", pageNumber];
UIFont* theFont = [UIFont systemFontOfSize:12];
CGSize pageNumberStringSize = [pageNumberString sizeWithFont:theFont
constrainedToSize:pageSize
lineBreakMode:NSLineBreakByWordWrapping];
CGRect stringRenderingRect = CGRectMake(kBorderInset,
pageSize.height - 40.0,
pageSize.width - 2*kBorderInset,
pageNumberStringSize.height);
[pageNumberString drawInRect:stringRenderingRect withFont:theFont lineBreakMode:NSLineBreakByWordWrapping alignment:NSTextAlignmentCenter];
}
- (void) drawHeader:(int)i;
{
CGContextRef currentContext = UIGraphicsGetCurrentContext();
//CGContextSetRGBFillColor(currentContext, 0.3, 0.7, 0.2, 1.0);
CGContextSetRGBFillColor(currentContext, 0.0f, 0.0f, 0.0f, 1);
//NSString *textToDraw = [NSString stringWithFormat:@"%@: %@ \n\nDate Range: %@ \n\nNumber of observations: %@",appDelegate.teacherName,@"Curriculum report",lblDate.text,lblNoOf.text];
NSString *textToDraw;
if(i<[arrReportTitles count])
textToDraw=[arrReportTitles objectAtIndex:i];
UIFont *font = [UIFont systemFontOfSize:16.0];
CGSize stringSize = [textToDraw sizeWithFont:font constrainedToSize:CGSizeMake(pageSize.width - 2*kBorderInset-2*kMarginInset, pageSize.height - 2*kBorderInset - 2*kMarginInset) lineBreakMode:NSLineBreakByWordWrapping];
CGRect renderingRect = CGRectMake(kBorderInset + kMarginInset, kBorderInset + kMarginInset, pageSize.width - 2*kBorderInset - 2*kMarginInset, stringSize.height);
[textToDraw drawInRect:renderingRect withFont:font lineBreakMode:NSLineBreakByWordWrapping alignment:NSTextAlignmentLeft];
//CGContextRelease(currentContext);
}
- (void) drawText
{
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(currentContext, 0.0, 0.0, 0.0, 1.0);
NSString *textToDraw = @"TeachersEvaluation";
UIFont *font = [UIFont systemFontOfSize:24.0];
CGSize stringSize = [textToDraw sizeWithFont:font
constrainedToSize:CGSizeMake(pageSize.width - 2*kBorderInset-2*kMarginInset, pageSize.height - 2*kBorderInset - 2*kMarginInset)
lineBreakMode:NSLineBreakByWordWrapping];
CGRect renderingRect = CGRectMake(kBorderInset + kMarginInset + 375, kBorderInset + kMarginInset + 450.0, pageSize.width - 2*kBorderInset - 2*kMarginInset, stringSize.height-50);
[textToDraw drawInRect:renderingRect
withFont:font
lineBreakMode:NSLineBreakByWordWrapping
alignment:NSTextAlignmentLeft];
//CGContextRelease(currentContext);
}
- (void) drawLine
{
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(currentContext, kLineWidth);
CGContextSetStrokeColorWithColor(currentContext, [UIColor grayColor].CGColor);
CGPoint startPoint = CGPointMake(kMarginInset + kBorderInset, kMarginInset + kBorderInset + 120.0);
CGPoint endPoint = CGPointMake(pageSize.width - 2*kMarginInset -2*kBorderInset, kMarginInset + kBorderInset + 120.0);
CGContextBeginPath(currentContext);
CGContextMoveToPoint(currentContext, startPoint.x, startPoint.y);
CGContextAddLineToPoint(currentContext, endPoint.x, endPoint.y);
CGContextClosePath(currentContext);
CGContextDrawPath(currentContext, kCGPathFillStroke);
//CGContextRelease(currentContext);
}
-(NSInteger) getImageHeighAndWidht : (NSInteger) value
{
value = value / 2;
if (value > 800 ) {
[self getImageHeighAndWidht:value];
}
if (value<450) {
value = value + (value/2);
}
return value;
}
- (void) drawImage: (UIImage *)fileName
{
CGSize mainImageSize;
UIImage *mainImage;
if (fileName.size.width > 542 || fileName.size.height > 742)
{
if (fileName.size.height > fileName.size.width) {
mainImageSize = CGSizeMake(470,575);
mainImage =fileName; //[fileName scaleProportionalToSize:mainImageSize];
} else {
mainImageSize = CGSizeMake(290,395);
mainImage = fileName;//[fileName scaleProportionalToSize:mainImageSize];
}
} else {
mainImageSize = CGSizeMake(fileName.size.width,fileName.size.height);
mainImage =fileName; //[fileName scaleProportionalToSize:mainImageSize];
}
float imageWidht;
if (mainImage.size.width > 542)
{
imageWidht = 542;
} else {
imageWidht = mainImage.size.width;
}
float imageHeight;
if (mainImage.size.height > 575)
{
imageHeight = 600.0;
} else {
imageHeight = mainImage.size.height;
}
//UIImage * demoImage = [UIImage imageNamed:fileName];
[mainImage drawInRect:CGRectMake( (pageSize.width - imageWidht)/2, 150, imageWidht, imageHeight)];
}
- (void) generatePdfWithFilePath: (NSString *)thefilePath
{
UIGraphicsBeginPDFContextToFile(thefilePath, CGRectZero, nil);
NSInteger currentPage = 0;
// _imgViewScreenShot.image=[arrMultiplePhots objectAtIndex:0];
// _imgViewScreenShot2.image=[arrMultiplePhots objectAtIndex:1];
for(int i = 0; i < [arrMultiplePhots count]; i++){
//Start a new page.
UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, pageSize.width, pageSize.height), nil);
//Draw a page number at the bottom of each page.
currentPage++;
[self drawPageNumber:currentPage];
//Draw a border for each page.
[self drawBorder];
//Draw text fo our header.
[self drawHeader:i];
//Draw a line below the header.
[self drawLine];
//if(i == 0) {
//currImage = [self.view imageByRenderingView];
//_imgViewScreenShot.image=currImage;
[self drawImage:[arrMultiplePhots objectAtIndex:i]];
//}
}
// Close the PDF context and write the contents out.
UIGraphicsEndPDFContext();
}
但是当我在循环内连续生成多个视图的图像时，我的应用程序崩溃并发出警告“应用程序因内存压力而崩溃”。
我使用仪器工具找出这次崩溃背后的原因，并且我在所有这些功能周围都有内存泄漏警告。
那么如何在上面的代码中解决这个内存泄漏问题？
修改
使用自动释放后，在上述功能中删除了内存泄漏
现在我在这个函数中出现内存泄漏
生成图像
- (UIImage *)imageByRenderingView
{
UIGraphicsBeginImageContext(self.bounds.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resultingImage;
}
答案 0 :(得分：1)
尝试此更改并告诉我它是否有帮助：
- (void) generatePdfWithFilePath: (NSString *)thefilePath
{
UIGraphicsBeginPDFContextToFile(thefilePath, CGRectZero, nil);
NSInteger currentPage = 0;
// _imgViewScreenShot.image=[arrMultiplePhots objectAtIndex:0];
// _imgViewScreenShot2.image=[arrMultiplePhots objectAtIndex:1];
for(int i = 0; i < [arrMultiplePhots count]; i++)
{
@autoreleasepool {
//Start a new page.
UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, pageSize.width, pageSize.height), nil);
//Draw a page number at the bottom of each page.
currentPage++;
[self drawPageNumber:currentPage];
//Draw a border for each page.
[self drawBorder];
//Draw text fo our header.
[self drawHeader:i];
//Draw a line below the header.
[self drawLine];
//if(i == 0) {
//currImage = [self.view imageByRenderingView];
//_imgViewScreenShot.image=currImage;
[self drawImage:[arrMultiplePhots objectAtIndex:i]];
//}
}
}
// Close the PDF context and write the contents out.
UIGraphicsEndPDFContext();
}