duoshoubang/FirstLink/Compoments/详情模块/Views/DetailNaviga...

//
//  DetailNavigationBar.m
//  FirstLink
//
//  Created by jack on 15/6/30.
//  Copyright (c) 2015年 FirstLink. All rights reserved.
//

#import "DetailNavigationBar.h"
#import "FLImageHelper.h"

@interface DetailNavigationBar ()
@property (nonatomic, strong) UIView        *circleBg;
@property (nonatomic, strong) UIImageView   *arrowImgView;
@property (nonatomic, strong) UIImageView   *bgImgView;
@end

@implementation DetailNavigationBar
@synthesize leftButton  = _leftButton;
@synthesize collectBtn  = _collectBtn;

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self initializeLayout];
    }
    return self;
}
- (void)initializeLayout
{
    self.backgroundColor = [UIColor clearColor];
    
    [self addSubview:self.bgImgView];
    [self addSubview:self.circleBg];
    [self addSubview:self.arrowImgView];
    [self addSubview:self.collectBtn];
    [self addSubview:self.leftButton];
//    [self addSubview:self.bottomLine];
    
    [self.bgImgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.insets(UIEdgeInsetsZero);
    }];
    
    [self.circleBg mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self).offset(20);
        make.centerY.equalTo(self.mas_bottom).offset(- 22);
        make.width.height.equalTo(@30);
    }];
    
    [self.arrowImgView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.circleBg).offset(-1);
        make.centerY.equalTo(self.circleBg);
    }];
    
    [self.collectBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.right.equalTo(self).offset(- 20);
        make.centerY.equalTo(self.circleBg);
        make.width.height.equalTo(@40);
    }];
    
    [self.leftButton mas_makeConstraints:^(MASConstraintMaker *make) {
        make.center.equalTo(self.circleBg);
        make.width.height.equalTo(@50);
    }];
}
-(void)setBgImgWithAlpha:(CGFloat)alpha
{
    UIColor *targetColor = [[UIColor blackColor] colorWithAlphaComponent:alpha];
    if (alpha < 0) targetColor = [UIColor clearColor];
    UIImage *image = [FLImageHelper imageWithColor:targetColor];
    self.bgImgView.image = image;
}
- (void)setCircleBgWithAlpha:(CGFloat)alpha
{
    self.circleBg.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:alpha];
}

- (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 collectStart = UISCREENWIDTH - 64 + 15;
        CGFloat collectMax = collectStart + 25;
        CGFloat max = 185.0f;
        CGFloat maxPercent = 0.80;      // 最大透明度
        CGFloat maxCirclePercent = 0.5; // 圆圈最大透明度
        CGPoint newPoint = [change[@"new"] CGPointValue];
        CGPoint oldPoint = [change[@"old"] CGPointValue];

        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 setCircleBgWithAlpha:(1 - alphaPercent) * maxCirclePercent];
        }
        if (newPoint.y < 0) return;
        
        // 改变收藏按钮(速度太快的时候)
        if (newPoint.y >= collectMax && oldPoint.y <= collectStart) {
            self.collectBtn.alpha = 1.0f;
            self.collectBtn.tag = 1;
            return;
        }else if (newPoint.y <= collectStart && oldPoint.y >= collectMax){
            self.collectBtn.alpha = 0;
            self.collectBtn.tag = 0;
            return;
        }
        
        if ((newPoint.y >= collectStart && newPoint.y <= collectMax) || (oldPoint.y > collectStart && oldPoint.y < collectMax)) {
            CGFloat collectAlpha = (collectMax - newPoint.y) / (collectMax - collectStart);
            if (self.collectBtn.tag == 0) {
                if (collectAlpha < 0) collectAlpha = 0;
                if (collectAlpha == 0 && oldPoint.y >= collectStart) self.collectBtn.tag = 1;
                self.collectBtn.alpha = 1 - collectAlpha;
            }else if (self.collectBtn.tag == 1){
                if (collectAlpha > 1) collectAlpha = 1;
                if (collectAlpha == 1) self.collectBtn.tag = 0;
                self.collectBtn.alpha = 1 - collectAlpha;
            }
        }
    }
    
}
#pragma mark - getter && setter
- (UIView *)circleBg
{
    if (_circleBg == nil) {
        _circleBg = [[UIView alloc]init];
        _circleBg.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.5];
        _circleBg.layer.cornerRadius = 15;
    }
    return _circleBg;
}
- (UIImageView *)arrowImgView
{
    if (_arrowImgView == nil) {
        _arrowImgView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"common_body_back_n"]];
    }
    return _arrowImgView;
}
- (UIButton *)collectBtn
{
    if (_collectBtn == nil) {
        _collectBtn = [UIButton buttonWithType:UIButtonTypeCustom];
        [_collectBtn setImage:[UIImage imageNamed:@"collectHeartN"] forState:UIControlStateNormal];
        [_collectBtn setImage:[UIImage imageNamed:@"collectHeartH"] forState:UIControlStateSelected];
        _collectBtn.alpha = 0;
    }
    return _collectBtn;
}
- (UIButton *)leftButton
{
    if (_leftButton == nil) {
        _leftButton = [UIButton buttonWithType:UIButtonTypeCustom];
    }
    return _leftButton;
}
- (UIImageView *)bgImgView
{
    if (_bgImgView == nil) {
        _bgImgView = [[UIImageView alloc]init];
        _bgImgView.backgroundColor = [UIColor clearColor];
    }
    return _bgImgView;
}
@end