当uitableview向上和向下滚动时，复选框状态发生变化

Question

我有一个tableview，其中有很多条目分为多个部分，里面有多行。我在每行中都有一个按钮模型化复选框。按下时可以启用/禁用复选框（按钮）。我正在加载一个图像的按钮（复选框）根据状态，无论是否检查。一切都很顺利，直到我试图向下拖动我的UITableview，然后往上走，才发现我的一些选中的复选框会自动取消选中。我有点认为，这是由于使用

dequeuereusablecellwithidentifier 

我想避免我的tableview这种奇怪的行为。在这种情况下需要帮助。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
static NSString *CellIdentifier = @"Cell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 
if (cell == nil) { 
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease]; 
    UIButton *checkBox = [[UIButton alloc] init]; 
    checkBox.tag = contact.contactID; 
    [cell.contentView addSubview:checkBox]; 
    [checkBox setFrame:CGRectMake(6,14,20,20)]; 
    [checkBox release]; 
} 
UIButton *checkBox = (UIButton *)[cell.contentView viewWithTag:contact.contactID]; 

if(isActivDeactivButton) 
{ 
    [checkBox setImage:[UIImage imageNamed:@"disabled_checkbox.png"] forState:UIControlStateNormal]; 
    } 
else{ 
    [checkBox setImage:[UIImage imageNamed:@"selected_checkbox.png"] forState:UIControlStateNormal]; 
} 
return cell; 
} 

Answer 1

我更换

checkBox.tag = contact.contactID; 

与

checkBox.tag = 111; 

这解决了问题，因为我的ContactID值滚动过程中发生变化。

Answer 2

确保您的-tableView:cellForRowAtIndexPath:逻辑设置如下：

// 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) { 
     // this part is called when the cell is created anew 
     cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; 
     // add new components here (this is where you'd add your checkbox control, etc) 
    } 

    // change the state of components here (this is where you'd make sure your checked property is set correctly 

    return cell; 
} 

使用dequeueReusableCellWithIdentifier:是内存管理的伟大实践，所以你要保持这个是肯定的。

Answer 3

// Add following methods def in viewController .h 

    -(void)checkButtonPressed:(id)sender; 
    -(void)addSelectedCheckBoxTag:(int)value; 
    -(void)deleteSelectedCheckBoxTag:(int)value; 
    -(BOOL)isSelectedCheckBox:(int)value; 

// add target to the check button in cellForRowAtIndexPath - 

    [checkBox addTarget:self action:@selector(checkButtonPressed:) forControlEvents:UIControlStateNormal]; 

// Ad following methods in viewController .m where tabelView 

    -(void)checkButtonPressed:(id)sender 
    { 
    UIButton *checkBox=(UIButton*)sender; 
    if(checkBox.selected) 
    { 
    checkBox.selected=false; 
    [checkBox setImage:[UIImage imageNamed:@"disabled_checkbox.png"] forState:UIControlStateNormal]; 
    [self deleteSelectedCheckBoxTag:checkBox.tag]; 
    NSLog(@"unselected .."); 
    } 
    else 
    { 
    checkBox.selected=true; 
    [self addSelectedCheckBoxTag:checkBox.tag]; 
    [checkBox setImage:[UIImage imageNamed:@"selected_checkbox.png"] forState:UIControlStateNormal];  
    NSLog(@"selected.."); 
    }  

} 

    // Add element in to array if already present forget 

    -(void)addSelectedCheckBoxTag:(int)value 
    { 
     int flag=0; 

    for(int i=0;i<[arrayForTag count];i++) 
    {   
     if([[arrayForTag objectAtIndex:i] intValue]==value) 
     flag=1; 
    } 
    if(flag==0) 
    [arrayForTag addObject:[NSString stringWithFormat:@"%d",value]]; 
    } 

    // delete element add in array if present 

    -(void)deleteSelectedCheckBoxTag:(int)value 
    { 

    for(int i=0;i<[arrayForTag count];i++) 
    {   
     if([[arrayForTag objectAtIndex:i] intValue]==value) 
     [arrayForTag removeObjectAtIndex:i]; 
    } 
    } 

    // For take is selected or not from array - 

-(BOOL)isSelectedCheckBox:(int)value 
    { 
    for(int i=0;i<[arrayForTag count];i++) 
    {   
     if([[arrayForTag objectAtIndex:i] intValue]==value) 
     return true; 
     } 
    return false; 
    } 

    // In cellForRowAtIndexPath replace following code 

    if(isActivDeactivButton) 
     { 
     [checkBox setImage:[UIImage imageNamed:@"disabled_checkbox.png"] forState:UIControlStateNormal]; 
     } 
else{ 
    [checkBox setImage:[UIImage imageNamed:@"selected_checkbox.png"] forState:UIControlStateNormal]; 
    } 

    // with following code - 

    if(![self isSelectedCheckBox:checkBox.tag]) 
    { 
     [checkBox setImage:[UIImage imageNamed:@"disabled_checkbox.png"] forState:UIControlStateNormal]; 
    } 
    else{ 
     [checkBox setImage:[UIImage imageNamed:@"selected_checkbox.png"] forState:UIControlStateNormal]; 
     }