IOS 中的下拉列表使用 Objective-C

Question

如何在 Objective-c 中使用带箭头符号的下拉菜单，单击按钮时会显示下拉列表。我需要在单个视图控制器上两次使用这些下拉菜单，已经看到很多链接，但是当我尝试创建第二个链接时，它显示任何错误或不在列表中显示数据。谁能帮帮我？？？？？

Answer 1

理解这里的概念..

我为你创建了一个非常简单易行的解决方案....我希望你能轻松理解它。

这里是我的代码：

故事板：

我先创建了 but1 到 but4。

然后我在图像中创建了表格视图。

ViewController.h

//button Actions
- (IBAction)but1:(UIButton *)sender;
- (IBAction)but2:(UIButton *)sender;
- (IBAction)but3:(UIButton *)sender;
- (IBAction)but4:(UIButton *)sender;
//table properties
@property (weak, nonatomic) IBOutlet UITableView *table1;
@property (weak, nonatomic) IBOutlet UITableView *table2;
@property (weak, nonatomic) IBOutlet UITableView *table3;
@property (weak, nonatomic) IBOutlet UITableView *table4;
//button properties
@property (weak, nonatomic) IBOutlet UIButton *but1;
@property (weak, nonatomic) IBOutlet UIButton *but2;
@property (weak, nonatomic) IBOutlet UIButton *but3;
@property (weak, nonatomic) IBOutlet UIButton *but4;

ViewController.m

#import "ViewController.h"

@interface ViewController ()<UIImagePickerControllerDelegate,UINavigationControllerDelegate,UITableViewDelegate,UITableViewDataSource>{
//    UIImagePickerController *picker;
    NSString *ImageViewC;
    NSArray *data;
    NSArray *data1;

}

@end

@implementation ViewController
@synthesize table1,table2,table3,table4;



- (void)viewDidLoad {
    [super viewDidLoad];
    data=[[NSArray alloc]initWithObjects:@"car1",@"car2",@"car1",@"car2", nil];
    data1=[[NSArray alloc]initWithObjects:@"house1",@"house2",@"house3",@"house4", nil];

    table2.dataSource=self;
    table1.dataSource=self;
    table3.dataSource=self;
    table4.dataSource=self;

    table2.delegate=self;
    table1.delegate=self;
    table3.delegate=self;
    table4.delegate=self;

    table1.hidden=YES;
    table2.hidden=YES;
    table3.hidden=YES;
    table4.hidden=YES;

//    picker = [[UIImagePickerController alloc]init];
//    picker.delegate=self;
//

}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)but1:(UIButton *)sender {
    ImageViewC=@"1";
    table1.hidden=NO;
    table2.hidden=YES;
    table3.hidden=YES;
    table4.hidden=YES;


    [table1 reloadData];
}

- (IBAction)but2:(UIButton *)sender {
    ImageViewC=@"2";
    table1.hidden=YES;
    table2.hidden=NO;
    table3.hidden=YES;
    table4.hidden=YES;

    [table2 reloadData];
//    [picker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
//    [self presentViewController:picker animated:YES completion:NULL];
}

- (IBAction)but3:(UIButton *)sender {
    ImageViewC=@"3";
    table1.hidden=YES;
    table2.hidden=YES;
    table3.hidden=NO;
    table4.hidden=YES;
    [table3 reloadData];

}

- (IBAction)but4:(UIButton *)sender {
    ImageViewC=@"4";
    table1.hidden=YES;
    table2.hidden=YES;
    table3.hidden=YES;
    table4.hidden=NO;
    [table4 reloadData];

}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}


// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if ([ImageViewC isEqualToString:@"1"])
        return [data count];
    else
        return [data1 count];

}


// Customize the appearance of table view cells.
- (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];
    }

    if ([ImageViewC isEqualToString:@"1"]) {
        cell.textLabel.text = [data objectAtIndex:indexPath.row];
    }else if([ImageViewC isEqualToString:@"2"]){
        cell.textLabel.text = [data1 objectAtIndex:indexPath.row];

    }else if ([ImageViewC isEqualToString:@"3"]){
        cell.textLabel.text=[data objectAtIndex:indexPath.row];
    }else{
        cell.textLabel.text=[data1 objectAtIndex:indexPath.row];


    }

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    UITableViewCell *selectedCell=[tableView cellForRowAtIndexPath:indexPath];
    NSLog(@"%@",selectedCell.textLabel.text);
    if ([ImageViewC isEqualToString:@"1"]) {
        [self.but1 setTitle:[NSString stringWithFormat:@"%@",selectedCell.textLabel.text] forState:UIControlStateNormal];

    }else  if ([ImageViewC isEqualToString:@"2"]){
        [self.but2 setTitle:[NSString stringWithFormat:@"%@",selectedCell.textLabel.text] forState:UIControlStateNormal];
    }else if ([ImageViewC isEqualToString:@"3"]){
        [self.but3 setTitle:[NSString stringWithFormat:@"%@",selectedCell.textLabel.text] forState:UIControlStateNormal];

    }else{
        [self.but4 setTitle:[NSString stringWithFormat:@"%@",selectedCell.textLabel.text] forState:UIControlStateNormal];

    }

    table1.hidden=YES;
    table2.hidden=YES;
    table3.hidden=YES;
    table4.hidden=YES;
}
@end

IOS 中的下拉列表使用 Objective-C

DropDown in IOS using Objective-C

objective-c

xcode8