Masonry+拖动

最近遇到一个问题，用Masonry写的布局；

拖动其中某个view，拖动方法按传统的写成如下形式。如果view中的label更改text值，拖动之后的view就会回到最初被设定的位置。

- (void)objectDidDragged:(UIPanGestureRecognizer *)paramSender {

    if (paramSender.state != UIGestureRecognizerStateEnded && paramSender.state != UIGestureRecognizerStateFailed){
        //通过使用 locationInView 这个方法,来获取到手势的坐标
        CGPoint location = [paramSender locationInView:paramSender.view.superview];
        paramSender.view.center = location;
    }
}

经试验后，拖动方法需改为如下所示：

//
//  ViewController.m
//  PanGesTest
//
//  Created by Vivien on 16/9/18.
//  Copyright © 2016年 Vivien. All rights reserved.
//
#import "Masonry.h"
#import "ViewController.h"

@interface ViewController ()
{
    
    NSTimer *timer ;
    int count;
    
    CGPoint panPoint;
}
@property (strong, nonatomic) UIView *panView;
@property (strong, nonatomic) UILabel *countLabel;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    _panView = [[UIView alloc]init];
    _panView.backgroundColor = [UIColor grayColor];
    [self.view addSubview:_panView];
    
    
    UIPanGestureRecognizer *panGR = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(objectDidDragged:)];
    //限定操作的触点数
    [panGR setMaximumNumberOfTouches:1];
    [panGR setMinimumNumberOfTouches:1];
    //将手势添加到draggableObj里
    [_panView addGestureRecognizer:panGR];
    
    [_panView mas_remakeConstraints:^(MASConstraintMaker *make) {
        make.top.mas_equalTo(self.view).offset(10);
        make.left.mas_equalTo(self.view).offset(30);
        make.width.mas_equalTo(150);
        make.height.mas_equalTo(50);
    }];
    
    _countLabel  = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, 100, 20)];
    [_countLabel setText:@"00000"];
    [_countLabel setTextColor:[UIColor redColor]];
    [_countLabel setTextAlignment:NSTextAlignmentCenter];
    [_countLabel setFont:[UIFont systemFontOfSize:13]];
    [_panView addSubview:_countLabel];
    
    [_countLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.top.mas_equalTo(_panView);
        make.height.mas_equalTo(20);
    }];
    
     timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(countAdd) userInfo:nil repeats:YES];
    [timer fire];

    count = 0;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)objectDidDragged:(UIPanGestureRecognizer *)sender {
    
    if (sender.state == UIGestureRecognizerStateBegan) {
        panPoint = [sender locationInView:_panView];
        
        NSLog(@"panPoint:%@",NSStringFromCGPoint(panPoint));
    }
    if (sender.state != UIGestureRecognizerStateEnded && sender.state != UIGestureRecognizerStateFailed)
    {
        CGPoint inViewLoction = [sender locationInView:self.view];//sender.view.superview
        CGPoint location = [sender translationInView:sender.view.superview];
        
        NSLog(@"locationInView:%@,translationInView:%@",NSStringFromCGPoint(inViewLoction),NSStringFromCGPoint(location));
//        sender.view.center = inViewLoction;
        [_panView mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.width.mas_equalTo(150);
            make.height.mas_equalTo(50);
            make.left.mas_equalTo(inViewLoction.x-panPoint.x);
            make.top.mas_equalTo(inViewLoction.y-panPoint.y);
//            make.left.mas_equalTo(0).offset(inViewLoction.x-panPoint.x);
//            make.top.mas_equalTo(0).offset(inViewLoction.y-panPoint.y);
        }];
        
        NSLog(@"className:%@",NSStringFromClass([sender.view.superview class]));
        [sender setTranslation:CGPointZero inView:self.view];
    }
}

- (void)countAdd
{
    count ++;
    [_countLabel setText:[NSString stringWithFormat:@"%d",count]];
}

@end