ios - objective-C - 如何在我的 TableView 中保留内存中的动态控制对象

Question

我正在用 objective-C 开发一个动态应用程序，它从 webServer 解析 XML 并向我的 tableView Controller 指定多少控件和哪些控件(标签、文本字段......应该打印，就像一个处方集)

问题是...如果我的屏幕无法显示所有控件，我会使用滚动条浏览我的所有场景，直到那时一切正常但是...当我这样做时，我所有的控件(标签, textfields) dissapear!!! 让我所有的 tableviewcells 都空着!!!

如果我释放滚动条并返回到原始位置(在顶部)，我的所有控件都会再次打印，但文本字段中的所有信息都消失了。

我猜这是因为内存的东西(内存力弱)，我怎样才能像属性一样(强)存储我所有的控件来让它们保持活力

注意:我无法控制我的 webService 通过 XML 发送的控件的数量和类型...

到目前为止我是这样做的:

@property (nonatomic, strong)   NSMutableArray  *controlsArray;
@property (nonatomic, strong)   UITableView     *myTableView;

- (void)viewDidLoad
{
    [super viewDidLoad];

    if ([[UIDevice currentDevice].model hasPrefix:@"iPhone"]){
        locationXLabel     = 20;
        locationXControl   = 150;
        widthLabel         = 130;
    }
    if ([[UIDevice currentDevice].model hasPrefix:@"iPad"]){
        locationXLabel     = 65;
        locationXControl   = 250;
        widthLabel         = 190;
    }
    locationYLabel     = 10;
    locationYControl   = 15;

    //WebService for printing controls
    if (!parBusResponseWebServ) parBusResponseWebServ = [[ParBusResponseWS alloc]imprimePantallaBusqueda];


    while ([parBusResponseWebServ transacWebServCompleto] == Nil) {
        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
    }

    //if webservice loads incomplete sends this message and exit
    if ([[parBusResponseWebServ transacWebServCompleto] isEqualToString:@"FALSE"] ||
        [[parBusResponseWebServ controlsList] count] <= 0) {
        parBusResponseWebServ = Nil;
        return;
    }


    self.controlsArray = [[NSMutableArray alloc]init];

    self.title = @"Búsqueda";


    if (!functions) functions = [[Functions alloc]init];

    [self createTableView];
}


-(void)createTableView{
    //this instance, creates, sets as a delegate and displays tableview
    self.myTableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)style:UITableViewStyleGrouped];
    self.myTableView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;

    self.myTableView.backgroundView             = nil;
    self.myTableView.backgroundColor            = UIColorFromRGB(tableViewBackgroundColor);
    self.myTableView.separatorColor             = UIColorFromRGB(tableViewSeparatorColor);
    self.myTableView.separatorStyle             = UITableViewCellSeparatorStyleSingleLineEtched;

    self.myTableView.delegate                   = self;
    self.myTableView.dataSource                 = self;
    [self.view addSubview:self.myTableView];
}



//Sets and returns the contents that will have each row of the table
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    NSString        *cellIdentifier = [NSString stringWithFormat:@"s%i-r%i", indexPath.section, indexPath.row];
    UITableViewCell *cell           = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
        cell.selectionStyle = UITableViewCellSelectionStyleNone;



        switch (indexPath.section) {
            case 0:
            {
                switch (indexPath.row) {
                    case 0:{
                        for (int i = 0; i < [parBusResponseWebServ.controlsList count]; i++) {

                            if ([[[parBusResponseWebServ.controlsList objectAtIndex:i]tipoControl] isEqualToString:@"TX"]) {

                                UILabel *label = [functions createLabel:[[parBusResponseWebServ.controlsList objectAtIndex:i] textoControl]
                                                              locationX:locationXLabel
                                                              locationY:locationYLabel
                                                             labelWidth:widthLabel
                                                            labelHeight:30
                                                            numLabelTag:tagControls
                                                        labelAdjustment:UIViewAutoresizingFlexibleRightMargin];

                                tagControls    += 1;

                                UITextField *textfield = [functions createTextField:@" "
                                                                          locationX:locationXControl
                                                                          locationY:locationYControl
                                                                    textFieldlWidth:150
                                                                    textFieldHeight:30
                                                                       keyboardType:UIKeyboardTypeDefault
                                                                    placeholderText:[[[parBusResponseWebServ.controlsList objectAtIndex:i]requerido] isEqualToString:@"TRUE"] ? @"Requerido***" : @"Introduce Texto"
                                                                    numTextFieldTag:tagControls
                                                                textFieldAdjustment:UIViewAutoresizingFlexibleWidth];

                                tagControls  += 1;

                                [cell addSubview:label];
                                [cell addSubview:textfield];

                                [self.controlsArray addObject:textfield];

                                locationYControl   += 45;
                                locationYLabel     += 45;
                            }

                            if ([[[parBusResponseWebServ.controlsList objectAtIndex:i]tipoControl] isEqualToString:@"CB"]) {

                                UILabel *label  = [functions createLabel:[[parBusResponseWebServ.controlsList objectAtIndex:i] textoControl] locationX:locationXLabel locationY:locationYLabel labelWidth:widthLabel labelHeight:30 numLabelTag:tagControls labelAdjustment:UIViewAutoresizingFlexibleRightMargin];

                                tagControls += 1;

                                UITextField *campotexto = [functions createTextField:@" "
                                                                           locationX:locationXControl
                                                                           locationY:locationYControl
                                                                     textFieldlWidth:120
                                                                     textFieldHeight:30
                                                                        keyboardType:UIKeyboardTypeDefault
                                                                     placeholderText:@"Seleccione"
                                                                     numTextFieldTag:tagControls
                                                                 textFieldAdjustment:UIViewAutoresizingFlexibleWidth];


                                tagControls += 1;

                                UIButton *button =[functions createButton:@" "
                                                                locationX:270
                                                                locationY:locationYLabel
                                                              buttonWidth:30
                                                             buttonHeight:30
                                                               buttonType:UIButtonTypeDetailDisclosure
                                                             numButtonTag:tagControls
                                                         buttonAdjustment:UIViewAutoresizingFlexibleLeftMargin];


                                [button addTarget:self action:@selector(action) forControlEvents:(UIControlEvents)UIControlEventTouchUpInside];

                                [cell addSubview:label];
                                [cell addSubview:campotexto];
                                [cell addSubview:button];

                                [self.controlsArray addObject:campotexto];

                                locationYControl   += 45;
                                locationYLabel     += 45;
                            }


                            if ([[[parBusResponseWebServ.controlsList objectAtIndex:i]tipoControl] isEqualToString:@"TA"]){

                                locationYControl     += 30;

                                UILabel *label = [functions createLabel:[[parBusResponseWebServ.controlsList objectAtIndex:i] textoControl]
                                                              locationX:locationXLabel
                                                              locationY:locationYLabel
                                                             labelWidth:widthLabel
                                                            labelHeight:30
                                                            numLabelTag:tagControls
                                                        labelAdjustment:UIViewAutoresizingFlexibleRightMargin];


                                tagControls    += 1;

                                UITextView *textView = [functions createTextArea:@" "
                                                                       locationX:locationXLabel
                                                                       locationY:locationYControl
                                                                  textViewlWidth:280
                                                                  textViewHeight:70
                                                                    keyboardType:UIKeyboardTypeDefault
                                                                  numTextViewTag:tagControls
                                                              textViewAdjustment:UIViewAutoresizingFlexibleRightMargin];

                                tagControls  += 1;

                                [cell addSubview:label];
                                [cell addSubview:textView];

                                [self.controlsArray addObject:textView];

                                locationYControl   += 135;
                                locationYLabel     += 130;
                            }
                        }
                    }
                        break;

                    default:
                        break;
                }
                break;

            default:
                break;
            }
        }
    }
    return cell;
}

Answer 1

这很可能发生，因为您的开关只创建索引路径 (0,0) 的 View ，没有创建其他索引路径...

还有你用错了单元格每行，每节 1 个单元格标识符？这根本不是在重用任何单元格(这还不错，但可以更好，按类型排列等)

好的，我明白了......发生的事情是你只为第一个单元格创建元素......仅为第一个单元格(第0节，第0行)创建每个控件，并将它们添加为 subview 一些偏移量(恰好等于标签高度)这是错误的。

就在第一行不再可见的那一刻，您的所有控件都消失了(请记住它们只是为第一行创建的(它们看起来像是在其他单元格上，但那是因为您将它们粘贴到单元格边界之外...)

你应该做的是。

YourClass *object = [parBusResponseWebServ.controlsList objectAtIndex:indexPath.row];

//With this object you can create the text
if ([[object tipoControl] isEqualToString:@"TX"]) {

                            UILabel *label = [functions createLabel:[object textoControl]
                                                          locationX:locationXLabel
                                                          locationY:locationYLabel
                                                         labelWidth:widthLabel
                                                        labelHeight:30
                                                        numLabelTag:tagControls
                                                    labelAdjustment:UIViewAutoresizingFlexibleRightMargin];

                            UITextField *textfield = [functions createTextField:@" "
                                                                      locationX:locationXControl
                                                                      locationY:locationYControl
                                                                textFieldlWidth:150
                                                                textFieldHeight:30
                                                                   keyboardType:UIKeyboardTypeDefault
                                                                placeholderText:[[object requerido] isEqualToString:@"TRUE"] ? @"Requerido***" : @"Introduce Texto"
                                                                numTextFieldTag:tagControls
                                                            textFieldAdjustment:UIViewAutoresizingFlexibleWidth];

                            tagControls  += 1;

                            [cell addSubview:label];
                            [cell addSubview:textfield];

                            [self.controlsArray addObject:textfield];

                        }

或者类似的...另外，如果我能说服你接受这种编程方式……你不应该使用标签，而应该使用已经在单元格上的标签

/*Prior to anything, create a NSMutableDictionary to hold the textfields that you are creating*/
self.textFieldDictionary = [[NSMutableDictionary alloc]init];

在 cellForRow 上

//Use only one reuse identifier (much quicker and less memory intensive)
static NSString *reuseIdentifier = @"cell";
UITableViewCell *cell = tableView dequeue....

if(!cell) {
   cell = [UITableViewCell alloc]initWithStyle:....

}


//Remove any other textfield
for (UIView *view in cell.contentView.subviews)
   [view removeFromSuperview];

cell.textLabel.text = [object textoControl];

/*Recover previously created TEXTFIELD*/
NSString *key = [[NSNumber numberWithInt:indexPath.row]stringValue];
UITextField *textField = [self.textFieldDictionary objectForKey:key];

if(!textField){
   textField = /*Create textfield*/
   [self.textFieldDictionary setObject:textField forKey:key]
}

[cell.contentView addSubview:textField]

return cell;

这样你就可以每行放置一个元素，而不是所有元素都放在一行上(在这种情况下，如果该行消失，其他元素也会消失)

我给了你最好的答案......我希望你使用 indexPath..它是你的 friend (或最大的敌人)