我需要做哪些优化才能为uitableview性能ipad做更多

Question

i have gone through different threads on stack overflow, and adopted them in my implementation of table view. some of them are:

tblOrderView.delaysContentTouches = NO;//order performance
tblOrderView.canCancelContentTouches = NO;//order performance
tblOrderView.showsHorizontalScrollIndicator = NO;//order performance

i am using different reload variants like reload rows at indexes and insert row at index paths, where ever possible instead of reload data.

i am reusing cell in proper way by c==nil check, creating content views in cell == nil and accessing content view by view with tag.

i am not fetching UIImage image name again and again, i keep a reference in instance variable.

My table view, cell and content have to be transparent as per design provided by client.

i am not sure about my heightForRowAtIndexPath implementation please have a look below cell for row.... implementation, it is working as expected. Problem: when i continue inserting row at index path after 30 to 35 insertions my table performance degrades (i am calling insert row not reload data for high performance). my cell for row relevant code is :

NSString *cellIdentifier=[NSString stringWithFormat:@"Modifiers%d",numberOfModifiers];;

customCell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
[customCell setSelected:NO animated:NO];
if(customCell==nil){
    [customCell setBackgroundColor:[UIColor clearColor]];
    customCell=[self reusableTableViewCellContent:cellIdentifier ForModifier:numberOfModifiers indexPath:indexPath];
}

reusableTableViewCellContent:cellIdentifier implementation is :

-(UITableViewCell *)reusableTableViewCellContent:(NSString *)identifier ForModifier:(int)_modifier indexPath:(NSIndexPath *)indexPath{

UITableViewCell *cell=nil;


//NSLog(@"%@",identifier);
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
cell.selectionStyle=UITableViewCellSelectionStyleNone;


CustomButton *btnDecimalQty=[[CustomButton alloc]initWithFrame:CGRectMake(5, 10, 57, 24)];

[btnDecimalQty setBackgroundImage:imgQuantity forState:UIControlStateNormal];
[btnDecimalQty setTag:DECIMAL_QUANTITY_BUTTON];
btnDecimalQty.titleLabel.font = [UIFont fontWithName:@"Arial-BoldMT" size:15.0];
[btnDecimalQty setTitleColor:[UIColor colorWithRed:71.0/255.0 green:72.0/255.0 blue:72.0/255.0 alpha:1.0] forState:UIControlStateNormal];
[btnDecimalQty addTarget:self action:@selector(openKeyPadPopUp:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:btnDecimalQty];

float prod_origin_x = btnDecimalQty.frame.origin.x + btnDecimalQty.frame.size.width + 5;



UILabel *productName=[[UILabel alloc]initWithFrame:CGRectMake(prod_origin_x , 8, 178, 30)]; //163, 140, 220, 30
//  [productName setText:@"Potato Wedges"];
[productName setFont:[UIFont fontWithName:@"Arial-BoldMT" size:[[Utils getFontSize] floatValue]]];
[productName setBackgroundColor:[UIColor clearColor]];
[productName setTextAlignment:UITextAlignmentLeft];
[productName setTextColor:[UIColor colorWithRed:45.0/255.0 green:44.0/255.0 blue:44.0/255.0 alpha:1.0]];
[productName setTag:PRODUCT_NAME_LABEL];
[cell.contentView addSubview:productName];


float action_button_origin_x = productName.frame.origin.x + productName.frame.size.width + 2;



CustomButton *edit=[[CustomButton alloc]initWithFrame:CGRectMake(action_button_origin_x, 14, 31, 23)];
[edit setTag:EDIT_BUTTON];


[edit setBackgroundImage:imgEdit forState:UIControlStateNormal];
[edit addTarget:self action:@selector(edit:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:edit];



CustomButton *discount=[[CustomButton alloc]initWithFrame:CGRectMake(edit.frame.origin.x+0 + edit.frame.size.width + 2, 14, 31, 23)];
[discount setTag:DISCOUNT_BUTTON];

[discount setBackgroundImage:imgDiscount forState:UIControlStateNormal];
[discount addTarget:self action:@selector(discount:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:discount];

float prod_amount_orgin_x = discount.frame.origin.x + discount.frame.size.width + 1;


UILabel *amount=[[UILabel alloc]initWithFrame:CGRectMake(prod_amount_orgin_x , 8, 65, 30)];
//  [amount setText:@"$ 70.00"];
[amount setBackgroundColor:[UIColor clearColor]];
[amount setTextAlignment:UITextAlignmentRight];
[amount setAdjustsFontSizeToFitWidth:YES];
[amount setFont:[UIFont fontWithName:@"Arial-BoldMT" size:[[Utils getFontSize] floatValue]]];
[amount setTextColor:[UIColor colorWithRed:71.0/255.0 green:72.0/255.0 blue:72.0/255.0 alpha:1.0]];
[amount setTag:AMOUNT_LABEL];
[cell.contentView addSubview:amount];


for(int i=0;i<_modifier ;i++)
{
    UILabel *modifierName=[[UILabel alloc]initWithFrame:CGRectMake(prod_origin_x, 30+(i*30), 220, 30)];
    //      [modifierName setText:@"Modifier 1"];
    [modifierName setFont:[UIFont fontWithName:@"Arial-BoldMT" size:[[Utils getFontSize] floatValue]]];
    [modifierName setBackgroundColor:[UIColor clearColor]];
    [modifierName setTextAlignment:UITextAlignmentLeft];
    [modifierName setTextColor:[UIColor colorWithRed:45.0/255.0 green:44.0/255.0 blue:44.0/255.0 alpha:1.0]];
    [modifierName setTag:MODIFIER_NAME_LABEL+(i*2)];
    [cell.contentView addSubview:modifierName];


    UILabel *modifierAmount=[[UILabel alloc]initWithFrame:CGRectMake(prod_amount_orgin_x, 30+(i*30), 65, 30)];
    //      [modifierAmount setText:@"$0.50"];
    [modifierAmount setBackgroundColor:[UIColor clearColor]];
    [modifierAmount setTextAlignment:UITextAlignmentRight];
    [modifierAmount setFont:[UIFont fontWithName:@"Arial-BoldMT" size:[[Utils getFontSize] floatValue]]];
    [modifierAmount setTextColor:[UIColor colorWithRed:71.0/255.0 green:72.0/255.0 blue:72.0/255.0 alpha:1.0]];
    [modifierAmount setTag:MODIFIER_AMOUNT_LABEL+(i*2)];
    [modifierAmount setAdjustsFontSizeToFitWidth:YES];
    [cell.contentView addSubview:modifierAmount];

}


    return cell;

}

my heightForRow implementation....

 - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    Product *product=(Product *)[self.arrOrderDetail objectAtIndex:indexPath.row];

    //Modifiers
    NSArray *modifierList=product.mModifiersAdded;
    int numberOfModifiers=0;
    for(Modifier *modifier in modifierList)
    {
        for(ModifierItem *modifierItem in modifier.activeModifiers)
        {
            numberOfModifiers++;
        }
    }

    OrderModule *module=[OrderModule sharedModule];
    numberOfModifiers=numberOfModifiers+[[module getActiveCustomModifiers:product.mOrderDetailId] count];


    //Non time based discount
    if([product.mNonTimeBasedDiscounts floatValue]>0.0)
    {
        numberOfModifiers++;
    }
    else if([product.mRuntimeDiscount floatValue]>0.0)       //Run time based discount
    {
        numberOfModifiers++;
    }
    else if([product.mTimeBasedDiscounts floatValue]>0.0)
    {
        numberOfModifiers++;
    }


    //Amount Modifier
    if(numberOfModifiers>0)
    {
        numberOfModifiers++;
    }

    CGFloat extraHeight=0.0;
    if(numberOfModifiers==0)
        extraHeight=15.0;
    return 30.0+extraHeight+(numberOfModifiers*30.0);
}

please suggest what more optimisations i can make to increase uitableview performance (reloading and scrolling)

Thanks.

Answer 1

I presume that you are setting the UILabel tags so that you can search for the fields when you providing the content? Why don't you create a custom UITableViewCell subclass that stores the labels in two NSMutableArrays? Then you can just select the appropriate label from the array rather than having to incur a linear search through the view hierarchy for every label in every cell?

When setting up your cell you call several methods inside the loops that could be called outside so you could have

UIFont *arialFont=[UIFont fontWithName:@"Arial-BoldMT" size:[[Utils getFontSize] floatValue]];
UIColor *amountColor=[UIColor colorWithRed:71.0/255.0 green:72.0/255.0 blue:72.0/255.0 alpha:1.0];
UIColor *nameColor=[UIColor colorWithRed:45.0/255.0 green:44.0/255.0 blue:44.0/255.0 alpha:1.0];

UILabel *amount=[[UILabel alloc]initWithFrame:CGRectMake(prod_amount_orgin_x , 8, 65, 30)];
//  [amount setText:@"$ 70.00"];
[amount setBackgroundColor:[UIColor clearColor]];
[amount setTextAlignment:UITextAlignmentRight];
[amount setAdjustsFontSizeToFitWidth:YES];
[amount setFont:arialFont];
[amount setTextColor:amountColor];
[amount setTag:AMOUNT_LABEL];
[cell.contentView addSubview:amount];


for(int i=0;i<_modifier ;i++)
{
    UILabel *modifierName=[[UILabel alloc]initWithFrame:CGRectMake(prod_origin_x, 30+(i*30), 220, 30)];
    //      [modifierName setText:@"Modifier 1"];
    [modifierName setFont: setFont:arialFont];
    [modifierName setBackgroundColor:[UIColor clearColor]];
    [modifierName setTextAlignment:UITextAlignmentLeft];
    [modifierName setTextColor: nameColor];
    [modifierName setTag:MODIFIER_NAME_LABEL+(i*2)];
    [cell.contentView addSubview:modifierName];


    UILabel *modifierAmount=[[UILabel alloc]initWithFrame:CGRectMake(prod_amount_orgin_x, 30+(i*30), 65, 30)];
    //      [modifierAmount setText:@"$0.50"];
    [modifierAmount setBackgroundColor:[UIColor clearColor]];
    [modifierAmount setTextAlignment:UITextAlignmentRight];
    [modifierAmount setFont: setFont:arialFont];
    [modifierAmount setTextColor:amountColor];
    [modifierAmount setTag:MODIFIER_AMOUNT_LABEL+(i*2)];
    [modifierAmount setAdjustsFontSizeToFitWidth:YES];
    [cell.contentView addSubview:modifierAmount];

}

Also, in this code -

for(Modifier *modifier in modifierList)
{
    for(ModifierItem *modifierItem in modifier.activeModifiers)
    {
        numberOfModifiers++;
    }
}

What type is modifier.activeModifiers ? If it is an NSArray or NSDictionary then the inner loop can simply be replaced with numberOfModifiers+=[modifier.activeModifiers count];