请注意：我知道在类似的行上有很多例子.我正在寻找最基本的解决方案,只需要最少的设置.
我试图自己创造一个,我知道我离开了..
#import "ViewController.h"
@interface ViewController () <UITableViewDataSource,UITableViewDelegate>
@property(strong,nonatomic) UITableView *tableView;
@property(strong,nonatomic) NSMutableArray *dataArray;
@property (strong,nonatomic) UITableViewCell *customCell;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view,typically from a nib.
self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(0,self.view.frame.size.width,self.view.frame.size.height) style:UITableViewStylePlain];
[self.tableView setDataSource:self];
[self.tableView setDelegate:self];
[self.tableView setShowsVerticalScrollIndicator:NO];
self.tableView.translatesAutoresizingMaskIntoConstraints = NO;
self.tableView.rowHeight = UITableViewAutomaticDimension;
[self.view addSubview:self.tableView];
self.dataArray = [@[@"For the past 33 years,I have looked in the mirror every morning and asked myself: 'If today were the last day of my life,would I want to do what I am about to do today?' And whenever the answer has been 'No' for too many days in a row,I know I need to change something. -Steve Jobs",@"Be a yardstick of quality. Some people aren't used to an environment where excellence is expected. - Steve Jobs",@"Innovation distinguishes between a leader and a follower. -Steve Jobs"] mutableCopy];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [self.dataArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *cellIdentifier = @"CustomCell";
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.backgroundColor = [UIColor colorWithRed:249.0/255 green:237.0/255 blue:224.0/255 alpha:1.0];
int dataIndex = (int) indexPath.row % [self.dataArray count];
cell.textLabel.text = self.dataArray[dataIndex];
cell.textLabel.numberOfLines = 0;
cell.textLabel.lineBreakMode = NSLineBreakByWordWrapping;
NSDictionary *views = @{@"label":cell.textLabel};
NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[label]|"
options:0
metrics:nil
views:views];
[cell.contentView addConstraints:constraints];
constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[label]|"
options: 0
metrics:nil
views:views];
[cell.contentView addConstraints:constraints];
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
// Calculate a height based on a cell
if(!self.customCell) {
self.customCell = [self.tableView dequeueReusableCellWithIdentifier:@"CustomCell"];
}
// Configure the cell
int dataIndex = (int) indexPath.row % [self.dataArray count];
self.customCell.textLabel.text = self.dataArray[dataIndex];
// auto layout
NSDictionary *views = @{@"label":self.customCell.textLabel};
NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[label]|"
options:0
metrics:nil
views:views];
[self.customCell.contentView addConstraints:constraints];
constraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[label]|"
options: 0
metrics:nil
views:views];
[self.customCell.contentView addConstraints:constraints];
// Layout the cell
[self.customCell layoutIfNeeded];
// Get the height for the cell
CGFloat height = [self.customCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
// Padding of 1 point (cell separator)
CGFloat separatorHeight = 1;
return height + separatorHeight;
}
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 140;
}
@end
解决方法
经过大量的例子,我终于明白了什么是错的.它是其中一个缺少线条会扰乱整个代码的东西之一.对我来说是,
cell.bodyLabel.preferredMaxLayoutWidth = tableView.bounds.size.width;
我们需要在heightForRowAtIndexPath方法中添加它或者它给出约束错误.
我得到了解决方案,感谢其中一个评论的惊人答案here.虽然在答案中给出的示例代码中,上面的代码行在函数cellForRowAtIndexPath而不是heightForRowAtIndexPath中.但我的代码无法以这种方式运行.
所以,基本代码是,
// RJCell.h
#import <UIKit/UIKit.h> @interface RJTableViewCell : UITableViewCell @property (strong,nonatomic) UILabel *titleLabel; @property (strong,nonatomic) UILabel *bodyLabel; @end
// RJCell.m
#import "RJTableViewCell.h"
@interface RJTableViewCell ()
@property (nonatomic,assign) BOOL didSetupConstraints;
@end
@implementation RJTableViewCell
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
// Initialization code
self.titleLabel = [[UILabel alloc] init];
[self.titleLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
[self.titleLabel setLineBreakMode:NSLineBreakByTruncatingTail];
[self.titleLabel setNumberOfLines:1];
[self.titleLabel setTextAlignment:NSTextAlignmentLeft];
[self.titleLabel setTextColor:[UIColor blackColor]];
[self.titleLabel setBackgroundColor:[UIColor clearColor]];
[self.contentView addSubview:self.titleLabel];
// Add this label to the button
self.bodyLabel = [[UILabel alloc] init];
[self.bodyLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
[self.bodyLabel setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];
[self.bodyLabel setLineBreakMode:NSLineBreakByTruncatingTail];
[self.bodyLabel setNumberOfLines:0];
[self.bodyLabel setTextAlignment:NSTextAlignmentLeft];
[self.bodyLabel setTextColor:[UIColor darkGrayColor]];
[self.bodyLabel setBackgroundColor:[UIColor clearColor]];
[self.contentView addSubview:self.bodyLabel];
}
return self;
}
- (void)updateConstraints {
[super updateConstraints];
if (self.didSetupConstraints) return;
// Get the views dictionary
NSDictionary *viewsDictionary =
@{
@"titleLabel" : self.titleLabel,@"bodyLabel" : self.bodyLabel
};
NSString *format;
NSArray *constraintsArray;
//Create the constraints using the visual language format
format = @"V:|-10-[titleLabel]-10-[bodyLabel]-10-|";
constraintsArray = [NSLayoutConstraint constraintsWithVisualFormat:format options:0 metrics:nil views:viewsDictionary];
[self.contentView addConstraints:constraintsArray];
format = @"|-10-[titleLabel]-10-|";
constraintsArray = [NSLayoutConstraint constraintsWithVisualFormat:format options:0 metrics:nil views:viewsDictionary];
[self.contentView addConstraints:constraintsArray];
format = @"|-10-[bodyLabel]-10-|";
constraintsArray = [NSLayoutConstraint constraintsWithVisualFormat:format options:0 metrics:nil views:viewsDictionary];
[self.contentView addConstraints:constraintsArray];
self.didSetupConstraints = YES;
}
@end
// RJTableViewController.h
#import <UIKit/UIKit.h> @interface RJTableViewController : UITableViewController @end
// RJTableViewController.m
#import "RJTableViewController.h"
#import "RJTableViewCell.h"
static NSString *CellIdentifier = @"CellIdentifier";
@interface RJTableViewController ()
@property(strong,nonatomic) NSMutableArray *titleArray;
@property(strong,nonatomic) NSMutableArray *bodyArray;
@end
@implementation RJTableViewController
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
self.title = @"Table View Controller";
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self.tableView registerClass:[RJTableViewCell class] forCellReuseIdentifier:CellIdentifier];
self.titleArray = [[UIFont familyNames] mutableCopy];
for(int i = 0; i < 100; i++) {
[self.titleArray addObjectsFromArray:[UIFont familyNames]];
}
self.bodyArray = [@[@"Lorem ipsum dolor sit amet,consectetur adipiscing elit,sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.",@"Ut enim ad minim veniam,quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.Ut enim ad minim veniam,quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.",@"Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.",@"Excepteur sint occaecat cupidatat non proident,sunt in culpa qui officia deserunt mollit anim id est laborum."] mutableCopy];
}
- (void)contentSizeCategoryChanged:(NSNotification *)notification
{
[self.tableView reloadData];
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return [self.titleArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
RJTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
int dataIndex = (int) indexPath.row % [self.bodyArray count];
cell.titleLabel.text = self.titleArray[indexPath.row];
cell.bodyLabel.text = self.bodyArray[dataIndex];
// Make sure the constraints have been added to this cell,since it may have just been created from scratch
[cell setNeedsUpdateConstraints];
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
RJTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
int dataIndex = (int) indexPath.row % [self.bodyArray count];
cell.titleLabel.text = self.titleArray[indexPath.row];
cell.bodyLabel.text = self.bodyArray[dataIndex];
cell.bodyLabel.preferredMaxLayoutWidth = tableView.bounds.size.width - (20.0 * 2.0f);
[cell setNeedsUpdateConstraints];
[cell updateConstraintsIfNeeded];
[cell.contentView setNeedsLayout];
[cell.contentView layoutIfNeeded];
CGFloat height = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
return height;
}
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 200.0f;
}
@end
基本上,棘手的部分是在两个地方,首先设置约束.二,实现方法heightForRowAtIndexPath和cellForRowAtIndexPath.
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