使用UITableViewCell和UITextField滚动问题

Question

I've got a little problem with my UITableViewCells. I've got 5 sections with different amount of rows in my tableView. I added each row a subview including a UITextfield. the problem i am having is, that when i scroll, my subviews of the cell are changing around. I took a video, so you can see what i mean.

http://files.beger.org/Scolling_Issue18072012.swf

Sorry that it is all in german :)

here is the code:

- (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];

// Add a UITextFiel
    if ([indexPath section] == 0) {
        UITextField *textFieldName = [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldName.adjustsFontSizeToFitWidth = YES;
        textFieldName.textColor = [UIColor blackColor];
        if ([indexPath row] == 0) {
            textFieldName.placeholder = @"Max";
            textFieldName.keyboardType = UIKeyboardTypeDefault;
            textFieldName.returnKeyType = UIReturnKeyDone;
        }
        else {
            textFieldName.placeholder = @"Mustermann";
            textFieldName.keyboardType = UIKeyboardTypeDefault;
            textFieldName.returnKeyType = UIReturnKeyDone;
        }       
        textFieldName.backgroundColor = [UIColor clearColor];
        textFieldName.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldName.autocapitalizationType = UITextAutocapitalizationTypeWords; // no auto capitalization support
        textFieldName.textAlignment = UITextAlignmentLeft;
        textFieldName.tag = 0;
        //playerTextField.delegate = self;

        textFieldName.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
        [textFieldName setEnabled: YES];

        [cell addSubview:textFieldName];

        [textFieldName release];
    }
    else if ([indexPath section] == 1) {
        UITextField *textFieldContactData = [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldContactData.adjustsFontSizeToFitWidth = YES;
        textFieldContactData.textColor = [UIColor blackColor];
        if ([indexPath row] == 0) {
            textFieldContactData.placeholder = @"04132 21123 321";
            textFieldContactData.keyboardType = UIKeyboardTypePhonePad;
        }
        else if ([indexPath row] == 1) {
            textFieldContactData.placeholder = @"04132 21123 300";
            textFieldContactData.keyboardType = UIKeyboardTypePhonePad;
        }
        else if ([indexPath row] == 2) {
            textFieldContactData.placeholder = @"0150 12543 101";
            textFieldContactData.keyboardType = UIKeyboardTypePhonePad;
        }
        else if ([indexPath row] == 3) {
            textFieldContactData.placeholder = @"beispiel@musterfirma.de";
            textFieldContactData.keyboardType = UIKeyboardTypeEmailAddress;
            textFieldContactData.returnKeyType = UIReturnKeyDone;
        }
        else if ([indexPath row] == 4) {
            textFieldContactData.placeholder = @"www.musterfirma.de";
            textFieldContactData.keyboardType = UIKeyboardTypeURL;
            textFieldContactData.returnKeyType = UIReturnKeyDone;
        }
        else {
            textFieldContactData.placeholder = @"Deutsch";
            textFieldContactData.keyboardType = UIKeyboardTypeDefault;
            textFieldContactData.returnKeyType = UIReturnKeyDone;
        }
        textFieldContactData.backgroundColor = [UIColor clearColor];
        textFieldContactData.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldContactData.autocapitalizationType = UITextAutocapitalizationTypeNone; // no auto capitalization support
        textFieldContactData.textAlignment = UITextAlignmentLeft;
        textFieldContactData.tag = 0;
        //playerTextField.delegate = self;

        textFieldContactData.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
        [textFieldContactData setEnabled: YES];

        [cell addSubview:textFieldContactData];

        [textFieldContactData release];
    }
    // Adresse
    else if ([indexPath section] == 2) {
        UITextField *textFieldAddress = [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldAddress.adjustsFontSizeToFitWidth = YES;
        textFieldAddress.textColor = [UIColor blackColor];
        if ([indexPath row] == 0) {
            textFieldAddress.placeholder = @"Musterstr. 10";
            textFieldAddress.keyboardType = UIKeyboardTypeDefault;
            textFieldAddress.autocapitalizationType = UITextAutocapitalizationTypeWords;
        }
        else if ([indexPath row] == 1) {
            textFieldAddress.placeholder = @"50000";
            textFieldAddress.keyboardType = UIKeyboardTypeDefault;
        }
        else if ([indexPath row] == 2) {
            textFieldAddress.placeholder = @"Musterstadt";
            textFieldAddress.keyboardType = UIKeyboardTypeDefault;
            textFieldAddress.autocapitalizationType = UITextAutocapitalizationTypeWords;
        }
        else {
            textFieldAddress.placeholder = @"Deutschland";
            textFieldAddress.keyboardType = UIKeyboardTypeDefault;
            textFieldAddress.autocapitalizationType = UITextAutocapitalizationTypeWords;
        }
        textFieldAddress.backgroundColor = [UIColor clearColor];
        textFieldAddress.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldAddress.autocapitalizationType = UITextAutocapitalizationTypeNone; // no auto capitalization support
        textFieldAddress.textAlignment = UITextAlignmentLeft;
        textFieldAddress.tag = 0;
        //playerTextField.delegate = self;

        textFieldAddress.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
        [textFieldAddress setEnabled: YES];

        [cell addSubview:textFieldAddress];

        [textFieldAddress release];
    }
    // Abteilung und Funktion
    else if ([indexPath section] == 3) {
        UITextField *textFieldFunction = [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldFunction.adjustsFontSizeToFitWidth = YES;
        textFieldFunction.textColor = [UIColor blackColor];
        if ([indexPath row] == 0) {
            textFieldFunction.placeholder = @"Einkauf";
            textFieldFunction.keyboardType = UIKeyboardTypeDefault;
            textFieldFunction.autocapitalizationType = UITextAutocapitalizationTypeWords;
        }
        else {
            textFieldFunction.placeholder = @"Einkaufsleiter";
            textFieldFunction.keyboardType = UIKeyboardTypeDefault;
            textFieldFunction.autocapitalizationType = UITextAutocapitalizationTypeWords;
        }
        textFieldFunction.backgroundColor = [UIColor clearColor];
        textFieldFunction.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldFunction.autocapitalizationType = UITextAutocapitalizationTypeNone; // no auto capitalization support
        textFieldFunction.textAlignment = UITextAlignmentLeft;
        textFieldFunction.tag = 0;
        //playerTextField.delegate = self;

        textFieldFunction.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
        [textFieldFunction setEnabled: YES];

        [cell addSubview:textFieldFunction];

        [textFieldFunction release];
    }
    // Kundenbeziehung
    else if ([indexPath section] == 4) {
        UITextField *textFieldCustomer= [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldCustomer.adjustsFontSizeToFitWidth = YES;
        textFieldCustomer.textColor = [UIColor blackColor];
        textFieldCustomer.placeholder = @"Musterfirma AG";
        textFieldCustomer.keyboardType = UIKeyboardTypeDefault;
        textFieldCustomer.backgroundColor = [UIColor clearColor];
        textFieldCustomer.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldCustomer.autocapitalizationType = UITextAutocapitalizationTypeNone; // no auto capitalization support
        textFieldCustomer.textAlignment = UITextAlignmentLeft;
        textFieldCustomer.tag = 0;

        textFieldCustomer.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
        [textFieldCustomer setEnabled: YES];

        [cell addSubview:textFieldCustomer];

        [textFieldCustomer release];
    }
    // Lieferantenbeziehung
    else {
        UITextField *textFieldSupplier= [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldSupplier.adjustsFontSizeToFitWidth = YES;
        textFieldSupplier.textColor = [UIColor blackColor];
        textFieldSupplier.placeholder = @"Lieferanten AG";
        textFieldSupplier.keyboardType = UIKeyboardTypeDefault;
        textFieldSupplier.backgroundColor = [UIColor clearColor];
        textFieldSupplier.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldSupplier.autocapitalizationType = UITextAutocapitalizationTypeNone; // no auto capitalization support
        textFieldSupplier.textAlignment = UITextAlignmentLeft;
        textFieldSupplier.tag = 0;

        textFieldSupplier.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
        [textFieldSupplier setEnabled: YES];

        [cell addSubview:textFieldSupplier];

        [textFieldSupplier release];
    }
}
if ([indexPath section] == 0) {
    if ([indexPath row] == 0) { 
        // Vorname
        cell.textLabel.text = @"Vorname";
    }
    else {
        // Nachname
        cell.textLabel.text = @"Nachname";
    }
}
// Kontaktdaten
else if ([indexPath section] == 1) {
    if ([indexPath row] == 0) { 
        cell.textLabel.text = @"Telefon";
    }
    else if ([indexPath row] == 1) {
         cell.textLabel.text = @"Fax";
    }
    else if ([indexPath row] == 2) {
        cell.textLabel.text = @"Mobil";
    }
    else if ([indexPath row] == 3) {
        cell.textLabel.text = @"E-Mail";
    }
    else if ([indexPath row] == 4) {
        cell.textLabel.text = @"WWW";
    }
    else {
        cell.textLabel.text = @"Sprache";
    }
}
// Adresse
else if ([indexPath section] == 2) {
    if ([indexPath row] == 0) { 
        cell.textLabel.text = @"Straße";
    }
    else if ([indexPath row] == 1) {
        cell.textLabel.text = @"PLZ";
    }
    else if ([indexPath row] == 2) {
        cell.textLabel.text = @"Ort";
    }
    else {
        cell.textLabel.text = @"Land";
    }
}
// Section Abteilung und Funktion
else if ([indexPath section] == 3) {
    if ([indexPath row] == 0) { 
        cell.textLabel.text = @"Abteilung";
    }
    else {
        cell.textLabel.text = @"Funktion";
    }
}
// Section Kundenbeziehung
else if ([indexPath section] == 4) {
        cell.textLabel.text = @"Kunde";
}
// Section Lieferantenbeziehung
else {
    cell.textLabel.text = @"Lieferant";
}
return cell;    

}

I think the cells can not store my data/subviews when i reuse them. Is there any way to solve the problem?

Thanks! Christoph

Answer 1

dequeueReusableCellWithIdentifier returns you reusable cell, if any. It means if some cell is not visible, iOS will not create a UITableViewCell again. It will directly return used cell. It makes performance better and memory utilization low.

So, when you identify cell is nil, you should create a cell and textfield. Add the textfiled as a subview of a cell.

Outside of cell is nil, you should provide other attributes of textfiled. You have done same thing for cell.textLable.text. You need to carry same exercise for textfiled also. To fetch the textField, tag while adding. Using that tag, you can fetch textField back.

static NSString *CellIdentifier = @"Cell";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

// Add a UITextFiel
    if ([indexPath section] == 0) {
        UITextField *textFieldName = [[UITextField alloc] initWithFrame:CGRectMake(120, 10, 185, 30)];
        textFieldName.adjustsFontSizeToFitWidth = YES;
        textFieldName.textColor = [UIColor blackColor];
        textFieldName.tag = 25;
        if ([indexPath row] == 0) {
            textFieldName.placeholder = @"Max";
            textFieldName.keyboardType = UIKeyboardTypeDefault;
            textFieldName.returnKeyType = UIReturnKeyDone;
 textFieldName.backgroundColor = [UIColor clearColor];
        textFieldName.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
        textFieldName.autocapitalizationType = UITextAutocapitalizationTypeWords; // no auto capitalization support
        textFieldName.textAlignment = UITextAlignmentLeft;
[cell addSubview:textFieldName];

        [textFieldName release];
        }
    }
}

//Here fetch the textFiled..
UITextFiled *tField = [cell viewWithTag:25];
//Identify row, section and do other operations like setting text, place holder etc...

Answer 2

You only add a UITextView if the cell is a newly created cell, so if the cell is re-used then the UITextview gets re-used as well. To get around this you could either:

Move all your UITextView creation code out of the if (cell == nil) statement

or

When you set the cell.textlabel.text find a way of accessing the textview thats already added to the cell (using the tag property, or looping through the subviews) and make changes to it.

Hope this helps.