@interface DropDown1 : UIView  {
    UITableView *tv;//下拉列表
    NSArray *tableArray;//下拉列表数据
    UITextField *textField;//文本输入框
    BOOL showList;//是否弹出下拉列表
    CGFloat tabheight;//table下拉列表的高度
    CGFloat frameHeight;//frame的高度
}
@property (nonatomic,retain) UITableView *tv;
@property (nonatomic,retain) NSArray *tableArray;
@property (nonatomic,retain) UITextField *textField;
@end
//****************************************************************************
@implementation DropDown1
@synthesize tv,tableArray,textField;
- (void)dealloc
{
    [tv release];
    [tableArray release];
    [textField release];
    [super dealloc];
}
-(id)initWithFrame:(CGRect)frame
{
    if (frame.size.height<200) {
        frameHeight = 200;
    }else{
        frameHeight = frame.size.height;
    }
    tabheight = frameHeight-30;
    
    frame.size.height = 30.0f;
    
    self=[super initWithFrame:frame];
    if(self){
        showList = NO; //默认不显示下拉框
        
        tv = [[UITableView alloc] initWithFrame:CGRectMake(0, 30, frame.size.width, 0)]; 
        tv.delegate = self;
        tv.dataSource = self;  
        tv.backgroundColor = [UIColor grayColor];  
        tv.separatorColor = [UIColor lightGrayColor];  
        tv.hidden = YES;  
        [self addSubview:tv];  
        textField = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, frame.size.width, 30)];
        textField.borderStyle=UITextBorderStyleRoundedRect;//设置文本框的边框风格
        [textField addTarget:self action:@selector(dropdown) forControlEvents:UIControlEventAllTouchEvents];
        [self addSubview:textField];
        
    }
    return self;
}
-(void)dropdown{
    [textField resignFirstResponder];
    if (showList) {//如果下拉框已显示，什么都不做
        return;
    }else {//如果下拉框尚未显示，则进行显示
        
        CGRect sf = self.frame;
        sf.size.height = frameHeight;
        
        //把dropdownList放到前面，防止下拉框被别的控件遮住
        [self.superview bringSubviewToFront:self];
        tv.hidden = NO;
        showList = YES;//显示下拉框
        
        CGRect frame = tv.frame;
        frame.size.height = 0;
        tv.frame = frame;
        frame.size.height = tabheight;
        [UIView beginAnimations:@"ResizeForKeyBoard" context:nil]; 
        [UIView setAnimationCurve:UIViewAnimationCurveLinear];  
        self.frame = sf;
        tv.frame = frame;
        [UIView commitAnimations];
    }
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [tableArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier]autorelease];
    }
    
    cell.textLabel.text = [tableArray objectAtIndex:[indexPath row]];
    cell.textLabel.font = [UIFont systemFontOfSize:16.0f];
    cell.accessoryType = UITableViewCellAccessoryNone;
    cell.selectionStyle = UITableViewCellSelectionStyleGray;
    
    return cell;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return 35;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    textField.text = [tableArray objectAtIndex:[indexPath row]];
    showList = NO;
    tv.hidden = YES;
    
    CGRect sf = self.frame;
    sf.size.height = 30;
    self.frame = sf;
    CGRect frame = tv.frame;
    frame.size.height = 0;
    tv.frame = frame;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
@end

 DropDown1 *dd1 = [[DropDown1 alloc] initWithFrame:CGRectMake(10, 10, 140, 100)];
 dd1.textField.placeholder = @"请输入联系方式";
 NSArray* arr=[[NSArray alloc]initWithObjects:@"电话",@"email",@"手机",@"aaa",@"bbb",@"ccc",nil];
 dd1.tableArray = arr;
 [arr release];
 [self.view addSubview:dd1];
 [dd1 release];

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