UI学习笔记---第十天UITableView表视图编辑

UITableView表视图编辑

表视图编辑的使用场景

当我们需要手动添加或者删除某条数据到tableView中的时候,就可以使用tableView编辑.比如微信 扣扣中删除和某人的通话

当我们需要手动调整单元格的顺序时,就可以通过tableView移动,移动单元格到指定位置

代理AppDelegate.m中代码

#import "AppDelegate.h"
#import "RootViewController.h"
@implementation AppDelegate
-(void)dealloc
{
    [_window release];
    [super dealloc];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    
    RootViewController *rootVC = [[RootViewController alloc] init];
    UINavigationController *ngVC = [[UINavigationController alloc] initWithRootViewController:rootVC];
    self.window.rootViewController = ngVC;
    
    [ngVC release];
    [rootVC release];

    [self.window makeKeyAndVisible];
    return YES;
}

RootViewController.h中建立一个可变数组属性 

 NSMutableArray *_mArr;

RootViewController.m中初始化和loadView代码

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.navigationItem.title = @"百家讲坛";
        self.navigationItem.rightBarButtonItem = self.editButtonItem;//控制器自带的编辑按钮
        _mArr = [[NSMutableArray alloc] initWithObjects:@"赵",@"钱",@"孙",@"李",@"周",@"武",@"郑",@"王",@"唐僧",@"孙悟空",@"猪八戒",@"沙僧",@"小白龙",@"二郎神",@"哪吒",@"雷震子", nil];
        // Custom initialization
    }
    return self;
}
-(void)loadView
{
    
    UITableView *table = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, 320, 480) style:UITableViewStyleGrouped];
    table.dataSource = self;
    table.delegate = self;
    self.view = table;
    [table release];

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [_mArr count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *identifier = @"reuse";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
    }
    cell.textLabel.text = [_mArr objectAtIndex:indexPath.row];
//    tableView.editing = YES;
    //cell右侧属性
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    return cell;
}

编辑的步骤

1.让tableView处于编辑状态

-(void)setEditing:(BOOL)editing animated:(BOOL)animated
{
    //调用父类方法,实现edit和done的变换
    [super setEditing:editing animated:animated];
    UITableView *tableView = (UITableView *)self.view;
    [tableView setEditing:editing animated:animated];
}

2.指定tableView那些行可以编辑

 //设置cell的可编辑状态,默认是yes
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
//    if (indexPath.row == 0) {
//        return YES;
//    }
    return YES;
}

3.指定tableView的编辑的样式(添加.删除)

//delegate中得方法
- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.row ==0) {
        return UITableViewCellEditingStyleInsert;//添加
    }
    return UITableViewCellEditingStyleDelete;//删除
}

4.编辑完成(先操作数据源,后修改UI)

//点击加号或者delete时触发的事件
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        [tableView beginUpdates];
        //删除数据  (写在删除cell前面  或者写一个[tableView beginUpdates]放前面一个[tableView endUpdates]放后面)
        [_mArr removeObjectAtIndex:indexPath.row];
        //删除cell
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationRight];
        [tableView endUpdates];
        NSLog(@"删除");
    }else{
        [tableView beginUpdates];
        [_mArr insertObject:@"hello" atIndex:indexPath.row];
        [tableView insertRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationRight];
        [tableView endUpdates];
        
        NSLog(@"添加");
    }
}

表视图的移动

移动的步骤

1.让tableView处于编辑状态

-(void)setEditing:(BOOL)editing animated:(BOOL)animated
{
    //调用父类方法,实现edit和done的变换
    [super setEditing:editing animated:animated];
    UITableView *tableView = (UITableView *)self.view;
    [tableView setEditing:editing animated:animated];
}

2.指定tableView哪些行可以移动

-(BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

3.移动完成

- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath *)destinationIndexPath
{
    NSString *str = [_mArr objectAtIndex:sourceIndexPath.row];
    
    //引用计数加1.避免出现野指针
    [str retain];
    
    
    //删除元素
    [_mArr removeObjectAtIndex:sourceIndexPath.row];
    //插入元素
    [_mArr insertObject:str atIndex:destinationIndexPath.row];
    
    [str release];//释放之前,retain的对象
}

监测移动过程,实现限制跨区移动

- (NSIndexPath *)tableView:(UITableView *)tableView targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath *)sourceIndexPath toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath
{
    NSLog(@"%d",sourceIndexPath.row);
    NSLog(@"%d",proposedDestinationIndexPath.row);
    if (sourceIndexPath.row == [_mArr count]-1) {
        return sourceIndexPath;
    }else{
    return proposedDestinationIndexPath;
    }
}

UITableViewController表视图控制器

继承自UIViewController

自带一个tableView,根视图就是tableView

模板自带编辑移动相关的代码