/*
分析:卡顿的原因!!
1.渲染图片耗时!! -- 分段!!
每次Runloop循环,最多需要加载18张大图!! 所以卡住了!!
思路:
每次Runloop循环,只渲染一张大图!!
步骤:
1.监听Runloop的循环!!
2.将加载大图的代码!放在一个数组里面!!
3.每次Runloop循环,取出一个加载大图的任务执行!!
*/

import "ViewController.h"

typedef void(^runloopBlock)(void);

static NSString * IDENTIFIER = @"IDENTIFIER";
static CGFloat CELL_HEIGHT = 135.f;

@interface ViewController ()<UITableViewDataSource,UITableViewDelegate>
@property (nonatomic, strong) UITableView *exampleTableView;
@property(nonatomic,strong)NSMutableArray * tasks;

@end

@implementation ViewController

-(void)timerMethod{
//不干任何事情!
}

• (void)viewDidLoad {
  [super viewDidLoad];

  [NSTimer scheduledTimerWithTimeInterval:0.0001 target:self selector:@selector(timerMethod) userInfo:nil repeats:YES];

_tasks = [NSMutableArray array];
         //注册Cell
[self.exampleTableView registerClass:[UITableViewCell class] forCellReuseIdentifier:IDENTIFIER];

[self addRunloopObserver];

}

//MARK: 内部实现方法

//添加文字
+(void)addlabel:(UITableViewCell *)cell indexPath:(NSIndexPath *)indexPath{
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(5, 5, 300, 25)];
label.backgroundColor = [UIColor clearColor];
label.textColor = [UIColor redColor];
label.text = [NSString stringWithFormat:@"%zd - Drawing index is top priority", indexPath.row];
label.font = [UIFont boldSystemFontOfSize:13];
label.tag = 4;
[cell.contentView addSubview:label];

UILabel *label1 = [[UILabel alloc] initWithFrame:CGRectMake(5, 99, 300, 35)];
label1.lineBreakMode = NSLineBreakByWordWrapping;
label1.numberOfLines = 0;
label1.backgroundColor = [UIColor clearColor];
label1.textColor = [UIColor colorWithRed:0 green:100.f/255.f blue:0 alpha:1];
label1.text = [NSString stringWithFormat:@"%zd - Drawing large image is low priority. Should be distributed into different run loop passes.", indexPath.row];
label1.font = [UIFont boldSystemFontOfSize:13];
label1.tag = 5;
[cell.contentView addSubview:label1];

}

//加载第一张
+(void)addImage1With:(UITableViewCell *)cell{
//第一张
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(5, 20, 85, 85)];
imageView.tag = 1;
NSString *path1 = [[NSBundle mainBundle] pathForResource:@"spaceship" ofType:@"png"];
UIImage *image = [UIImage imageWithContentsOfFile:path1];
imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.image = image;
[UIView transitionWithView:cell.contentView duration:0.3 options:(UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionTransitionCrossDissolve) animations:^{
[cell.contentView addSubview:imageView];
} completion:nil];
}

//加载第二张
+(void)addImage2With:(UITableViewCell *)cell{
//第二张
UIImageView *imageView1 = [[UIImageView alloc] initWithFrame:CGRectMake(105, 20, 85, 85)];
imageView1.tag = 2;
NSString *path1 = [[NSBundle mainBundle] pathForResource:@"spaceship" ofType:@"png"];
UIImage *image1 = [UIImage imageWithContentsOfFile:path1];
imageView1.contentMode = UIViewContentModeScaleAspectFit;
imageView1.image = image1;
[UIView transitionWithView:cell.contentView duration:0.3 options:(UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionTransitionCrossDissolve) animations:^{
[cell.contentView addSubview:imageView1];
} completion:nil];
}
//加载第三张
+(void)addImage3With:(UITableViewCell *)cell{
//第三张
UIImageView *imageView2 = [[UIImageView alloc] initWithFrame:CGRectMake(200, 20, 85, 85)];
imageView2.tag = 3;
NSString *path1 = [[NSBundle mainBundle] pathForResource:@"spaceship" ofType:@"png"];
UIImage *image2 = [UIImage imageWithContentsOfFile:path1];
imageView2.contentMode = UIViewContentModeScaleAspectFit;
imageView2.image = image2;
[UIView transitionWithView:cell.contentView duration:0.3 options:(UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionTransitionCrossDissolve) animations:^{
[cell.contentView addSubview:imageView2];
} completion:nil];
}

//MARK: UI初始化方法
//设置tableview大小

• (void)viewWillAppear:(BOOL)animated {
  [super viewWillAppear:animated];
  self.exampleTableView.frame = self.view.bounds;
  }

//Cell 高度

• (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
  return CELL_HEIGHT;
  }

//加载tableview

• (void)loadView {
  self.view = [UIView new];
  self.exampleTableView = [UITableView new];
  self.exampleTableView.delegate = self;
  self.exampleTableView.dataSource = self;
  [self.view addSubview:self.exampleTableView];
  }

pragma mark - <tableview>

• (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
  return 399;
  }

• (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:IDENTIFIER];
  cell.selectionStyle = UITableViewCellSelectionStyleNone;

//干掉contentView上面的子控件!! 节约内存!!
for (NSInteger i = 1; i <= 5; i++) {
    //干掉contentView 上面的所有子控件!!
    [[cell.contentView viewWithTag:i] removeFromSuperview];
}
//添加文字
[ViewController addlabel:cell indexPath:indexPath];
//添加图片
[self addTasks:^{
    [ViewController addImage1With:cell];
}];

[self addTasks:^{
    [ViewController addImage2With:cell];
}];

[self addTasks:^{
    [ViewController addImage3With:cell];
}];


return cell;

}

pragma mark - <CFRunloop>

-(void)addTasks:(runloopBlock)task{

[self.tasks addObject:task];
if (self.tasks.count > 18) {
    [self.tasks removeObjectAtIndex:0];
}

}

//一下都是C语言的!!
-(void)addRunloopObserver{
//获取Runloop
CFRunLoopRef runloop = CFRunLoopGetCurrent();
//定义一个context
CFRunLoopObserverContext context = {
0,
(__bridge void *)(self),
&CFRetain,
&CFRelease,
NULL
};

//定义观察者
static CFRunLoopObserverRef runloopObserver;
runloopObserver = CFRunLoopObserverCreate(NULL, kCFRunLoopBeforeWaiting, YES, 0, &callBack, &context);

//添加观察者
CFRunLoopAddObserver(runloop, runloopObserver, kCFRunLoopCommonModes);


//C里面 一旦creat new copy
CFRelease(runloopObserver);

}

void callBack(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info){
ViewController * vc = (__bridge ViewController *)info;
if(vc.tasks.count == 0){
return;
}
runloopBlock block = vc.tasks.firstObject;
block();
[vc.tasks removeObjectAtIndex:0];

}

@end