下拉框组件的实现在代码

最新推荐文章于 2024-05-07 15:03:14 发布

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最新推荐文章于 2024-05-07 15:03:14 发布

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分类专栏： objective c 文章标签： uiview action interface 2010 list

本文链接：https://blog.youkuaiyun.com/ssihc0/article/details/6741789

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本文详细介绍了如何在UI视图中实现下拉框组件，涵盖了组件的创建、交互动作处理以及接口调用等内容，适用于2010年后的开发实践。通过实例代码，帮助开发者理解并掌握这一常见前端控件的实现技巧。

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//
//  ComboBoxView.h
//  comboBox
//
//  Created by duansong on 10-7-28.
//  Copyright 2010 __MyCompanyName__. All rights reserved.
//

#import <UIKit/UIKit.h>


@interface ComboBoxView : UIView < UITableViewDelegate, UITableViewDataSource > {
	UILabel			*_selectContentLabel;
	UIButton		*_pulldownButton;
	UIButton		*_hiddenButton;
	UITableView		*_comboBoxTableView;
	NSArray			*_comboBoxDatasource;
	BOOL			_showComboBox;
}

@property (nonatomic, retain) NSArray *comboBoxDatasource;

- (void)initVariables;
- (void)initCompentWithFrame:(CGRect)frame;
- (void)setContent:(NSString *)content;
- (void)show;
- (void)hidden;
- (void)drawListFrameWithFrame:(CGRect)frame withContext:(CGContextRef)context;

@end

//
//  ComboBoxView.m
//  comboBox
//
//  Created by duansong on 10-7-28.
//  Copyright 2010 __MyCompanyName__. All rights reserved.
//

#import "ComboBoxView.h"


@implementation ComboBoxView

@synthesize comboBoxDatasource = _comboBoxDatasource;

- (id)initWithFrame:(CGRect)frame {
    if ((self = [super initWithFrame:frame])) {
		[self initVariables];
		[self initCompentWithFrame:frame];
    }
    return self;
}

#pragma mark -
#pragma mark custom methods

- (void)initVariables {
	_showComboBox = NO;
}

- (void)initCompentWithFrame:(CGRect)frame {
	_selectContentLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, 0, frame.size.width - 45, 25)];
	_selectContentLabel.font = [UIFont systemFontOfSize:14.0f];
	_selectContentLabel.backgroundColor = [UIColor clearColor];
	[self addSubview:_selectContentLabel];
	[_selectContentLabel release];
	
	_pulldownButton = [UIButton buttonWithType:UIButtonTypeCustom];
	[_pulldownButton setFrame:CGRectMake(frame.size.width - 25, 0, 25, 25)];
	[_pulldownButton setBackgroundImage:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"list_ico_d" ofType:@"png"]]
							   forState:UIControlStateNormal];
	[_pulldownButton addTarget:self action:@selector(pulldownButtonWasClicked:) forControlEvents:UIControlEventTouchUpInside];
	[self addSubview:_pulldownButton];
	
	_hiddenButton = [UIButton buttonWithType:UIButtonTypeCustom];
	[_hiddenButton setFrame:CGRectMake(0, 0, frame.size.width - 25, 25)];
	_hiddenButton.backgroundColor = [UIColor clearColor];
	[_hiddenButton addTarget:self action:@selector(pulldownButtonWasClicked:) forControlEvents:UIControlEventTouchUpInside];
	[self addSubview:_hiddenButton];
	
	_comboBoxTableView = [[UITableView alloc] initWithFrame:CGRectMake(1, 26, frame.size.width -2, frame.size.height - 27)];
	_comboBoxTableView.dataSource = self;
	_comboBoxTableView.delegate = self;
	_comboBoxTableView.backgroundColor = [UIColor clearColor];
	_comboBoxTableView.separatorColor = [UIColor blackColor];
	_comboBoxTableView.hidden = YES;
	[self addSubview:_comboBoxTableView];
	[_comboBoxTableView release];
}

- (void)setContent:(NSString *)content {
	_selectContentLabel.text = content;
}

- (void)show {
	_comboBoxTableView.hidden = NO;
	_showComboBox = YES;
	[self setNeedsDisplay];
}

- (void)hidden {
	_comboBoxTableView.hidden = YES;
	_showComboBox = NO;
	[self setNeedsDisplay];
}

#pragma mark -
#pragma mark custom event methods

- (void)pulldownButtonWasClicked:(id)sender {
	if (_showComboBox == YES) {
		[self hidden];
	}else {
		[self show];
	}
}

#pragma mark -
#pragma mark UITableViewDelegate and UITableViewDatasource methods

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

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
	static NSString *CellIdentifier = @"ListCellIdentifier";
	UITableViewCell *cell = [_comboBoxTableView dequeueReusableCellWithIdentifier:CellIdentifier];
	if (cell == nil) {
		cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
	}
	cell.textLabel.text = (NSString *)[_comboBoxDatasource objectAtIndex:indexPath.row];
	cell.textLabel.font = [UIFont systemFontOfSize:13.0f];
	cell.accessoryType = UITableViewCellAccessoryNone;
	cell.selectionStyle = UITableViewCellSelectionStyleNone;
	
	return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
	return 25.0f;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
	[self hidden];
	_selectContentLabel.text = (NSString *)[_comboBoxDatasource objectAtIndex:indexPath.row];
}

- (void)drawListFrameWithFrame:(CGRect)frame withContext:(CGContextRef)context {
	CGContextSetLineWidth(context, 2.0f);
	CGContextSetRGBStrokeColor(context, 0.0f, 0.0f, 0.0f, 1.0f);
	if (_showComboBox == YES) {
		CGContextAddRect(context, CGRectMake(0.0f, 0.0f, frame.size.width, frame.size.height));
		
	}else {
		CGContextAddRect(context, CGRectMake(0.0f, 0.0f, frame.size.width, 25.0f));
	}
	CGContextDrawPath(context, kCGPathStroke);	
	CGContextMoveToPoint(context, 0.0f, 25.0f);
	CGContextAddLineToPoint(context, frame.size.width, 25.0f);
	CGContextMoveToPoint(context, frame.size.width - 25, 0);
	CGContextAddLineToPoint(context, frame.size.width - 25, 25.0f);
	
	CGContextStrokePath(context);
}


#pragma mark -
#pragma mark drawRect methods

- (void)drawRect:(CGRect)rect {
	[self drawListFrameWithFrame:self.frame withContext:UIGraphicsGetCurrentContext()];
}


#pragma mark -
#pragma mark dealloc memery methods

- (void)dealloc {
	_comboBoxTableView.delegate		= nil;
	_comboBoxTableView.dataSource	= nil;
	
	[_comboBoxDatasource			release];
	_comboBoxDatasource				= nil;
	
    [super dealloc];
}


@end

使用方法

- (void)viewDidLoad {
    [super viewDidLoad];
	
	NSArray *comboBoxDatasource = [[NSArray alloc] initWithObjects:@"one", @"two", @"three", @"four", @"five", @"six", @"seven", @"eight", nil];
	_comboBox = [[ComboBoxView alloc] initWithFrame:CGRectMake(20, 20, 280, 140)];
	_comboBox.comboBoxDatasource = comboBoxDatasource;
	_comboBox.backgroundColor = [UIColor clearColor];
	[_comboBox setContent:[comboBoxDatasource objectAtIndex:0]];
	[self.view addSubview:_comboBox];
	[_comboBox release];
	[comboBoxDatasource release];
}