+ (AFHTTPSessionManager*)defaultNetManager {ios代码
static AFHTTPSessionManager *manager;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
manager = [[AFHTTPSessionManager alloc]init];
manager.responseSerializer = [AFHTTPResponseSerializer serializer];
});
return manager;
}
+ (void)GET:(NSString*)url parameters:(NSDictionary*)parameter returnData:(void (^)(NSData * resultData,NSError * error))returnBlock{
//请求队列管理者 单例创建形式 防止内存泄漏
AFHTTPSessionManager * manager = [HttpRequest defaultNetManager];
[manager GET:url parameters:parameter progress:^(NSProgress * _Nonnull downloadProgress) {
} success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
returnBlock(responseObject,nil);
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
returnBlock(nil,error);
}];
}
self.tableView.mj_header = [MJRefreshNormalHeader headerWithRefreshingBlock:^{若在MJRefresh的执行Block中调用当前self或其所属属性,一定要注意循环引用问题。我们简单分析下MJRefresh为什么会造成循环引用问题:
self.page = 1;
[self.dataArr removeAllObjects];
[self loadData];
}];
+ (instancetype)headerWithRefreshingBlock:(MJRefreshComponentRefreshingBlock)refreshingBlock
{
MJRefreshHeader *cmp = [[self alloc] init];
cmp.refreshingBlock = refreshingBlock;
return cmp;
}
__weak typeof(self) weakself = self;
self.tableView.mj_header = [MJRefreshNormalHeader headerWithRefreshingBlock:^{
__strong typeof(self) strongself = weakself;
strongself.page = 1;
[strongself.dataArr removeAllObjects];
[strongself loadData];
}];
@property (nonatomic, weak) id<CustomDelegate> delegate;
#import "TestNSTimer.h"
@interface TestNSTimer ()
@property (nonatomic, strong) NSTimer *timer;
@end
@implementation TestNSTimer
- (instancetype)init {
if (self = [super init]) {
_timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timeRefresh:) userInfo:nil repeats:YES];
}
return self;
}
- (void)timeRefresh:(NSTimer*)timer {
NSLog(@"TimeRefresh...");
}
- (void)cleanTimer {
[_timer invalidate];
_timer = nil;
}
- (void)dealloc {
[super dealloc];
NSLog(@"销毁");
[self cleanTimer];
}
@end
TestNSTimer *timer = [[TestNSTimer alloc]init];最后的执行结果为
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[timer release];
});
CIImage *beginImage = [[CIImage alloc]initWithImage:[UIImage imageNamed:@"yourname.jpg"]];在如上代码中的CGImageRef类型变量非OC对象,其需要手动执行释放操作CGImageRelease(ref),否则会造成大量的内存泄漏导致程序崩溃。其他的对于CoreFoundation框架下的某些对象或变量需要手动释放、C语言代码中的malloc等需要对应free等都需要注意。
CIFilter *filter = [CIFilter filterWithName:@"CIColorControls"];
[filter setValue:beginImage forKey:kCIInputImageKey];
[filter setValue:[NSNumber numberWithFloat:.5] forKey:@"inputBrightness"];//亮度-1~1
CIImage *outputImage = [filter outputImage];
//GPU优化
EAGLContext * eaglContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES3];
eaglContext.multiThreaded = YES;
CIContext *context = [CIContext contextWithEAGLContext:eaglContext];
[EAGLContext setCurrentContext:eaglContext];
CGImageRef ref = [context createCGImage:outputImage fromRect:outputImage.extent];
UIImage *endImg = [UIImage imageWithCGImage:ref];
_imageView.image = endImg;
CGImageRelease(ref);//非OC对象需要手动内存释放
- (void)clearMapView{六、大次数循环内存暴涨问题
self.mapView = nil;
self.mapView.delegate =nil;
self.mapView.showsUserLocation = NO;
[self.mapView removeAnnotations:self.annotations];
[self.mapView removeOverlays:self.overlays];
[self.mapView setCompassImage:nil];
}
for (int i = 0; i < 100000; i++) {该循环内产生大量的临时对象,直至循环结束才释放,可能导致内存泄漏,解决方法为在循环中创建自己的autoReleasePool,及时释放占用内存大的临时变量,减少内存占用峰值。
NSString *string = @"Abc";
string = [string lowercaseString];
string = [string stringByAppendingString:@"xyz"];
NSLog(@"%@", string);
}
for (int i = 0; i < 100000; i++) {若对autoReleasePool陌生,可查阅相关资料,毕竟不是一两句即可说明的。
@autoreleasepool {
NSString *string = @"Abc";
string = [string lowercaseString];
string = [string stringByAppendingString:@"xyz"];
NSLog(@"%@", string);
}
}
来自: jianshu
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