duoshoubang/FirstLink/Compoments/详情模块/商品详情/View/FKProductNav...

//
//  FKProductNavigationBar.m
//  FirstLink
//
//  Created by jack on 16/1/13.
//  Copyright © 2016年 FirstLink. All rights reserved.
//

#import "FKProductNavigationBar.h"
#import "FLImageHelper.h"

@interface FKProductNavigationBar ()

@property (nonatomic, strong) UIImageView   *bgImgView;
@property (nonatomic, strong) UIView        *bottomLine;

@end

@implementation FKProductNavigationBar
- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self addAllSubviews];
    }
    return self;
}

- (void)addAllSubviews{
    
    self.backgroundColor = [UIColor clearColor];
    
    [self addSubview:self.bgImgView];
    [self addSubview:self.backBtn];
    [self addSubview:self.shareBtn];
    [self addSubview:self.bottomLine];
    
    [self.bgImgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.insets(UIEdgeInsetsZero);
    }];
    
    [self.backBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.mas_left).offset(28);
        make.centerY.equalTo(self.mas_bottom).offset(- 22);
        make.size.mas_equalTo(CGSizeMake(50, 50));
    }];
    
    [self.shareBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.mas_right).offset(- 25);
        make.centerY.equalTo(self.backBtn);
        make.width.height.mas_equalTo(50);
    }];
    
    [self.bottomLine mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.bottom.right.equalTo(self);
        make.height.mas_equalTo(1.0);
    }];
}

-(void)setBgImgWithAlpha:(CGFloat)alpha{
    
    UIColor *targetColor = [[UIColor whiteColor] colorWithAlphaComponent:alpha];
    if (alpha < 0) targetColor = [UIColor clearColor];
    UIImage *image = [FLImageHelper imageWithColor:targetColor];
    self.bgImgView.image = image;
}

- (void)setBottomLineWithAlpha:(CGFloat)alpha{
    UIColor *targetColor = [UIColorFromRGB(0xe5e5e5) colorWithAlphaComponent:alpha];
    if (alpha < 0) targetColor = [UIColor clearColor];
    self.bottomLine.backgroundColor = targetColor;
}

- (void)setStatusBarWithAlphaPerCent:(CGFloat)alphaPercent{
    
    UIStatusBarStyle style = [UIApplication sharedApplication].statusBarStyle;
    UIStatusBarStyle targetSty = UIStatusBarStyleDefault;
    
    if (alphaPercent >= 0 && alphaPercent <= 0.5){
        targetSty = UIStatusBarStyleLightContent; // 白色
    }
    if (targetSty == style) return;
    [[UIApplication sharedApplication] setStatusBarStyle:targetSty animated:NO];
}


- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"contentOffset"]) {

        CGFloat maxPercent = 1.0f;      // 最大透明度
        CGPoint newPoint = [change[@"new"] CGPointValue];
        CGPoint oldPoint = [change[@"old"] CGPointValue];
        
        if ([object isKindOfClass:[UITableView class]]) {
            
            UITableView *tableView = (UITableView *)object;
            CGFloat max = UISCREENWIDTH;
            
            if (tableView.superview.tag == 1) return;
            if (CGPointEqualToPoint(newPoint, oldPoint)) return;
            
            // 改变navBar背景
            CGFloat alphaPercent = newPoint.y / max;
            if (!(alphaPercent >= 1.0f && oldPoint.y >= max)){
                [self setBgImgWithAlpha:MIN(alphaPercent * maxPercent, maxPercent)];
                [self setBottomLineWithAlpha:MIN(alphaPercent * maxPercent, maxPercent)];
            }
            if (newPoint.y < 0) return;
            
        } else if ([object isKindOfClass:[UIScrollView class]]) {
            
            UIScrollView *scrollView = (UIScrollView *)object;
            CGFloat max = CGRectGetHeight(scrollView.bounds) - 44 - 20;
        
            if (CGPointEqualToPoint(newPoint, oldPoint)) return;
            if (newPoint.y == 0) newPoint.y = max;
            // 改变navBar背景
            CGFloat alphaPercent = newPoint.y / max;
            if (!(alphaPercent >= 1.0f && oldPoint.y >= max)){
                [self setBgImgWithAlpha:MIN(alphaPercent * maxPercent, maxPercent)];
                [self setBottomLineWithAlpha:MIN(alphaPercent * maxPercent, maxPercent)];
            }
        }
    }
    
}

#pragma mark - property

- (UIButton *)backBtn{
    if (_backBtn == nil) {
        _backBtn = [UIButton buttonWithType:UIButtonTypeCustom];
        [_backBtn setImage:[UIImage imageNamed:@"fk_common_back"] forState:UIControlStateNormal];
    }
    return _backBtn;
}

- (UIButton *)shareBtn{
    if (_shareBtn == nil) {
        _shareBtn = [UIButton buttonWithType:UIButtonTypeCustom];
        [_shareBtn setImage:[UIImage imageNamed:@"product_make_money"] forState:UIControlStateNormal];
    }
    return _shareBtn;
}

- (UIImageView *)bgImgView{
    if (_bgImgView == nil) {
        _bgImgView = [[UIImageView alloc]init];
        _bgImgView.backgroundColor = [UIColor clearColor];
    }
    return _bgImgView;
}

- (UIView *)bottomLine{
    if (_bottomLine == nil) {
        _bottomLine = [[UIView alloc]init];
        _bottomLine.backgroundColor = [UIColorFromRGB(0xe5e5e5) colorWithAlphaComponent:0.0];
    }
    return _bottomLine;
}
@end