###ViewController 瘦身实践
当ViewController要实现UITableView DataSource时，很多时候cell的展示样式都是一样的，如果把很多业务逻辑都写进ViewController，ViewController 会臃肿，且很多代码都是重复的。出于使用最少的代码实现最多的功能之目的，可以将ITableView DataSource抽取出来，这样很多ViewController可以共用一个自定义的DataSource，不单可以节省很多代码，ViewController也显得清洁好看。
ArrayDataSource.h
#import <UIKit/UIKit.h>
typedef void (^TableViewCellConfigureBlockWithItem)(id cell, id item);//因为要复用，所以要写成id类型
@interface ArrayDataSource : NSObject<UITableViewDataSource>
@property(nonatomic,strong) NSArray *items;
@property(nonatomic,strong) NSString *cellIdentifier;
@property(nonatomic,copy) TableViewCellConfigureBlockWithItem configureCellBlock;
- (id)initWithItems:(NSArray *)anItems
cellIdentifier:(NSString *)aCellIdentifier
configureCellBlock:(TableViewCellConfigureBlockWithItem)aConfigureCellBlock;
- (NSInteger)tableView:(UITableView*)tableView
numberOfRowsInSection:(NSInteger)section;
- (UITableViewCell*)tableView:(UITableView*)tableView
cellForRowAtIndexPath:(NSIndexPath*)indexPath;
@end
ArrayDataSource.m:
#import "ArrayDataSource.h"
@interface ArrayDataSource ()
@end
@implementation ArrayDataSource
@synthesize items,cellIdentifier;
- (id)initWithItems:(NSArray *)anItems
cellIdentifier:(NSString *)aCellIdentifier
configureCellBlock:(TableViewCellConfigureBlockWithItem)aConfigureCellBlock
{
self = [super init];
if (self) {
self.items = anItems;
self.cellIdentifier = aCellIdentifier;
self.configureCellBlock = [aConfigureCellBlock copy];
}
return self;
}
- (NSInteger)tableView:(UITableView*)tableView
numberOfRowsInSection:(NSInteger)section {
return self.items.count;
}
- (UITableViewCell*)tableView:(UITableView*)tableView
cellForRowAtIndexPath:(NSIndexPath*)indexPath {
id cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier
forIndexPath:indexPath];
id item = [self itemAtIndexPath:indexPath];
self.configureCellBlock(cell,item);
return cell;
}
- (id)itemAtIndexPath:(NSIndexPath *)indexPath
{
return self.items[(NSUInteger) indexPath.row];
}
@end
LoginViewController.m:
#import "LoginViewController.h"
#import "LoginCell.h"
#import "ArrayDataSource.h"
#import "LoginCellModel.h"
@interface LoginViewController ()<UITableViewDelegate>
@property (weak, nonatomic) IBOutlet UITableView *myTableView;
@property (nonatomic,strong) ArrayDataSource * arrayDataSource;
@end
@implementation LoginViewController
@synthesize arrayDataSource;
#pragma mark - UIView LifeCycle Methods
- (void)viewDidLoad {
[super viewDidLoad];
void (^configureCell)(LoginCell *cell,LoginCellModel *cellModel) = ^(LoginCell* cell,LoginCellModel *cellModel) {
cell.selectionStyle = UITableViewCellSelectionStyleNone;
[cell setContent:cellModel];
};
NSString *cellIndentifier = @"Cell";
NSArray *items = [self createCellModels];
// 需要注册，否则会crash
[self.myTableView registerNib:[UINib nibWithNibName:@"LoginCell" bundle:[NSBundle mainBundle]] forCellReuseIdentifier:cellIndentifier];
arrayDataSource = [[ArrayDataSource alloc] initWithItems:items
cellIdentifier:cellIndentifier
configureCellBlock:configureCell];
[self customTableViewShowStyle];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
#pragma mark - custom methods
-(NSArray *)createCellModels {
LoginCellModel * nameModel = [[LoginCellModel alloc] init];
nameModel.imageName = @"uid";
nameModel.placeHolderStr = @"请输入用户名";
LoginCellModel * pwdModel = [[LoginCellModel alloc] init];
pwdModel.imageName = @"pwd";
pwdModel.placeHolderStr = @"请输入登录密码";
NSMutableArray * items = [[NSMutableArray alloc] init];
[items addObject:nameModel];
[items addObject:pwdModel];
return items;
}
#pragma mark - 设置TableView显示样式
-(void)customTableViewShowStyle {
self.myTableView.dataSource = arrayDataSource;
self.myTableView.tableHeaderView = [[UIView alloc] init];
self.myTableView.tableFooterView = [[UIView alloc] init];
self.myTableView.scrollEnabled = NO;
//1.调整(iOS7以上)表格分隔线边距
if ([self.myTableView respondsToSelector:@selector(setSeparatorInset:)]) {
self.myTableView.separatorInset = UIEdgeInsetsZero;
}
//2.调整(iOS8以上)view边距(或者在cell中设置preservesSuperviewLayoutMargins,二者等效)
if ([self.myTableView respondsToSelector:@selector(setLayoutMargins:)]) {
self.myTableView.layoutMargins = UIEdgeInsetsZero;
}
}
@end
LoginCell.h:
#import <UIKit/UIKit.h>
#import "LoginCellModel.h"
@interface LoginCell : UITableViewCell
@property (weak, nonatomic) IBOutlet UIImageView *myImgView;
@property (weak, nonatomic) IBOutlet UITextField *myTxtField;
-(void)setContent:(LoginCellModel *)model;
@end
LoginCell.m:
#import "LoginCell.h"
@implementation LoginCell
- (void)awakeFromNib {
[super awakeFromNib];
}
- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
[super setSelected:selected animated:animated];
}
#pragma mark - Custom Methods
-(void)setContent:(LoginCellModel *)model{
self.myImgView.image = [UIImage imageNamed:model.imageName];
self.myTxtField.placeholder = model.placeHolderStr;
}
@end
#import <Foundation/Foundation.h>
@interface LoginCellModel : NSObject
@property(nonatomic,strong) NSString * imageName;
@property(nonatomic,strong) NSString * placeHolderStr;
@end