在 UIButton 中实现切换功能

Question

我想知道如何向 UIButton 添加切换功能，例如用户点击未选择的按钮，该按钮将被选中并保持选中状态，直到用户再次点击它，就像以前一样取消选择。

我正在考虑制作一个 IBAction ，将其从未选中更改为选中，我该怎么做？

这是我尝试过的：

-(IBAction)toggle {

    //Toggle on implementation.

        button.selected = YES;
        button.highlighted = NO;
        button.enabled = YES;

    //Toggle off implementation.

    if (button.highlighted == YES) {

        button.selected = NO;
        button.highlighted = YES;
        button.enabled = NO;
    }
}

问题...

-(IBAction)toggleFav {

    if (favButton == nil) {

        UIImage *unselectedImage = [UIImage imageNamed:@"favUntapped.png"];
        UIImage *selectedImage = [UIImage imageNamed:@"favTapped.png"];
        [favButton setImage:unselectedImage forState:UIControlStateNormal];
        [favButton setImage:selectedImage forState:UIControlStateSelected];
        [favButton setFrame:CGRectMake(0, 0, 40, 40)];
    }       

    if([favButton isSelected]){

        //Add to menu.
        [favButton setSelected:NO];
    } else {

        //Remove from menu.

        [favButton setSelected:YES];
    }
}

Answer 1

- (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];
        UIImage *unselectedImage = [UIImage imageNamed:@"unselected.png"];
        UIImage *selectedImage = [UIImage imageNamed:@"selected.png"];
        UIButton *b = [UIButton buttonWithType:UIButtonTypeCustom];
        [b setBackgroundImage:unselectedImage forState:UIControlStateNormal];
        [b setBackgroundImage:selectedImage forState:UIControlStateSelected];
        [b addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
        [b setFrame:CGRectMake(0, 0, 40, 40)];
        [cell.contentView addSubview:b];
    }       
    return cell;
}

-(void) buttonPressed:(UIButton *)sender
{
    if([sender isSelected]){
        //...
        [sender setSelected:NO];
    } else {
        //...    
        [sender setSelected:YES];
    }

}

您的 toggleFav 代码没有多大意义。
if (favButton == nil) { 检查 favButton 是否存在。但如果你用 IB 连接它，它应该总是在那一点上。如果不是的话，按钮怎么会调用这个方法呢？所以这样做：

-(void)viewDidLoad
{
    //....
    UIImage *unselectedImage = [UIImage imageNamed:@"favUntapped.png"];
    UIImage *selectedImage = [UIImage imageNamed:@"favTapped.png"];
    [favButton setImage:unselectedImage forState:UIControlStateNormal];
    [favButton setImage:selectedImage forState:UIControlStateSelected];
    [favButton setFrame:CGRectMake(0, 0, 40, 40)];
    //....
}


-(IBAction)toggleFav:(UIButton *)sender {
    if([sender isSelected]){
        //...
        [sender setSelected:NO];
    } else {
        //...    
        [sender setSelected:YES];
    }
}

在这里你会找到一个示例项目，带有一个 DetaiView，其中包含一个具有 2 个状态的 Button。
注意：我正在 NSUserDefaults 中保存所选按钮的信息。你不应该那样做。相反，您需要将其保存在模型中。但由于我没有关于你的模型的信息，我只是使用 NSUserDefaults。

Answer 2

-(void)hitButton:(UIButton*)button
{
    buttonOnFlag = !buttonOnFlag;
    if( buttonFlag )
        [self performSelector:@selector(setHighlight:) withObject:button afterDelay:0];
}

- (void)setHighlight:(UIButton*)button 
{
    button.highlighted = true;
}

Answer 3

使用button.highlighted属性

Answer 4

你应该这样编码：

-(IBAction)toggle:(id)sender {

    //Toggle on implementation.
   if (sender.highlighted == NO)
     {
        sender.selected = YES;
        sender.highlighted = NO;
        sender.enabled = YES;
     }

    //Toggle off implementation.

   else{

        sender.selected = NO;
        sender.highlighted = YES;
        sender.enabled = NO;
    }
}