CellSizeCalculator.h

//
//  CellSizeCalculator.h
//
//  Created by Moritz Haarmann on 19.09.12.
//  Copyright (c) 2012 n/a. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface CSCLabelElement : NSObject

@property (nonatomic,copy) NSString* title;
@property (nonatomic,strong) UIFont* usedFont;

@end

@interface CSCFixedSizeElement : NSObject

@property (nonatomic) float verticalHeight;

@end

@interface CellSizeCalculator : NSObject

/**
 * Contains the saved views for each cell registered.
 */
@property (nonatomic,strong) NSMutableDictionary* savedViews;
@property (nonatomic,strong) NSMutableDictionary* savedConstraints;


/**
 * Takes the name of a xib containing one tableviewcell subclass.
 */
-(void)registerCellWithXib:(NSString*)xibName dynamicViews:(NSArray*)mappableView;

- (CGFloat)heightForCell:(NSString *)name withKeyValueDictionary:(NSDictionary *)keyValuesForLabels inTableView:(UITableView*)tableView withAccessory:(BOOL)accessory;

- (CGFloat)heightForCell:(NSString *)name withKeyValueDictionary:(NSDictionary *)keyValuesForLabels inTableView:(UITableView*)tableView;
- (void)layoutCell:(UITableViewCell *)cell;

/**
 * Shared instance.
 */
+(CellSizeCalculator*)sharedInstance;
@end

CellSizeCalculator.m

//
//  CellSizeCalculator.m
//
//  Created by Moritz Haarmann on 19.09.12.
//  Copyright (c) 2012 n/a. All rights reserved.
//

#import "CellSizeCalculator.h"
#import <CoreText/CoreText.h>
#import "UITableView+Padding.h"
static CellSizeCalculator *staticInstance;

@implementation CellSizeCalculator

- (id)init {
    self = [super init];
    if(self) {
        self.savedConstraints = [NSMutableDictionary new];
        self.savedViews = [NSMutableDictionary new];
    }

    return self;
}

/**
 * Takes the name of a xib containing one tableviewcell subclass.
 */
- (void)registerCellWithXib:(NSString *)xibName dynamicViews:(NSArray *)mappableViews {
    if ( [self.savedConstraints objectForKey:xibName]){
        return;
    }
    UITableViewCell *loadedCell = [[[NSBundle mainBundle] loadNibNamed:xibName owner:nil options:nil] objectAtIndex:0];

    assert(loadedCell);

    NSMutableArray *ownConstraints = [NSMutableArray new];

    NSMutableDictionary *temporaryNameToViewMapping = [NSMutableDictionary new];

    // After the cell is loaded, we need to built a vertical list of items that consists of fixed spaces
    // and the label placeholders for later use in the real layout.

    NSMutableArray *collectedMappableViews = [NSMutableArray new];
    for(NSString *viewPropertyName in mappableViews) {
        UILabel *retrievedLabel = [loadedCell valueForKey:viewPropertyName];
        assert(retrievedLabel);
        [collectedMappableViews addObject:retrievedLabel];
        [temporaryNameToViewMapping setObject:viewPropertyName forKey:[NSNumber numberWithFloat:retrievedLabel.frame.origin.y].stringValue];
    }

    // No we have an unordered list of elements which we need to sort.

    NSArray *sortedViews = [collectedMappableViews sortedArrayUsingDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"originY" ascending:YES]]];

    int lastOffset = 0;

    for(UILabel *label in sortedViews) {
        int newOffset = label.frame.origin.y - lastOffset;

        if(newOffset) {
            CSCFixedSizeElement *fixedSize = [CSCFixedSizeElement new];
            fixedSize.verticalHeight = newOffset;
            [ownConstraints addObject:fixedSize];
        }

        lastOffset += newOffset;

        CSCLabelElement *labelElement = [CSCLabelElement new];

        labelElement.title = [temporaryNameToViewMapping valueForKey:[NSNumber numberWithFloat:label.frame.origin.y].stringValue];

        labelElement.usedFont = label.font;

        [ownConstraints addObject:labelElement];

        lastOffset += label.frame.size.height;
    }


    // Bottom Padding

    UILabel *lastElement = [sortedViews lastObject];

    CGFloat distanceToBottom = loadedCell.frame.size.height - lastElement.frame.size.height - lastElement.frame.origin.y;

    CSCFixedSizeElement *fixedSizeBottomPadding = [CSCFixedSizeElement new];
    fixedSizeBottomPadding.verticalHeight = distanceToBottom;

    [ownConstraints addObject:fixedSizeBottomPadding];

    for(id anyConstraint in ownConstraints) {
        if([anyConstraint isKindOfClass:[CSCFixedSizeElement class]]) {
            DDLogVerbose(@"Fixed Size, Height: %f", [anyConstraint verticalHeight]);
        } else {
            DDLogVerbose(@"Label Class");
        }
    }

    [self.savedConstraints setObject:ownConstraints forKey:NSStringFromClass([loadedCell class])];
    [self.savedViews setObject:loadedCell forKey:NSStringFromClass([loadedCell class])];
}
- (CGFloat)heightForCell:(NSString *)name withKeyValueDictionary:(NSDictionary *)keyValuesForLabels inTableView:(UITableView*)tableView {
    return [self heightForCell:name withKeyValueDictionary:keyValuesForLabels inTableView:tableView withAccessory:NO];
}


- (CGFloat)heightForCell:(NSString *)name withKeyValueDictionary:(NSDictionary *)keyValuesForLabels inTableView:(UITableView*)tableView withAccessory:(BOOL)accessory{
    
    CGFloat viewWidth = tableView.frame.size.width - tableView.paddingSize*2;
    
    if ( accessory) {
        viewWidth -= 60;
    }
    
    NSArray *constraints = [self.savedConstraints objectForKey:name];

   // assert(constraints);
    // ios 5 quick fix.
    if ( !constraints){
        return 0;
    }
    assert(viewWidth);

    UITableViewCell *savedCell = [self.savedViews objectForKey:name];

  //  assert(savedCell);

    // Resize to the given width, so that autosizing works.
    [savedCell setFrame:CGRectMake(0, 0, viewWidth, savedCell.frame.size.height)];
    

    [savedCell layoutSubviews];
    CGFloat calculatedHeight = 0;
    BOOL skipNext = NO;

    for(id anyConstraint in constraints) {
        // Simply add Vertical Heights
        if ( skipNext ){
            // One field skipped because a label was empty..
            skipNext = NO;
        }
        else if([anyConstraint isKindOfClass:[CSCFixedSizeElement class]]) {
            calculatedHeight += [anyConstraint verticalHeight];
        } else if([anyConstraint isKindOfClass:[CSCLabelElement class]]) {
            CSCLabelElement *labelConstraint = (CSCLabelElement *)anyConstraint;

            NSString *labelText = (NSString *)[keyValuesForLabels objectForKey:labelConstraint.title];
            // Have a value for the current label?

            if(labelText && labelText.length > 0) {
                // calculate the height of the label given the current width
                UILabel *labelToUse = [savedCell valueForKey:[anyConstraint title]];
                CGSize sizeWithText;
                if ( labelToUse.numberOfLines < 2 ){
                    sizeWithText = [labelText sizeWithFont:labelToUse.font];
                } else {
                    sizeWithText = [labelText sizeWithFont:labelToUse.font constrainedToSize:CGSizeMake(labelToUse.frame.size.width, CGFLOAT_MAX) lineBreakMode:labelToUse.lineBreakMode];
                }
                
                
                calculatedHeight += sizeWithText.height;

            } else {
                // SKip next.
                skipNext = YES;
            }
        }
    }
    
    return calculatedHeight;
}

- (void)layoutCell:(UITableViewCell *)cell {
    NSString* cellName = NSStringFromClass([cell class]);
    
    NSArray* constraints = [self.savedConstraints objectForKey:cellName];
    
    if (!constraints){
        return;
    }
    assert(constraints);
    
    
    CGFloat calculatedHeight = 0;
    BOOL skipNext = NO;
    
    for(id anyConstraint in constraints) {
        // Simply add Vertical Heights
        if ( skipNext ){
            // One field skipped because a label was empty..
            skipNext = NO;
        }
        else if([anyConstraint isKindOfClass:[CSCFixedSizeElement class]]) {
            calculatedHeight += [anyConstraint verticalHeight];
        } else if([anyConstraint isKindOfClass:[CSCLabelElement class]]) {
            CSCLabelElement *labelConstraint = (CSCLabelElement *)anyConstraint;
            
            UILabel* labelInCell = [cell valueForKey:labelConstraint.title];
            
            
            // Have a value for the current label?
            
            if(labelInCell.text.length > 0) {
                // calculate the height of the label given the current width
               
                
                CGSize sizeWithText;
                if ( labelInCell.numberOfLines < 2 ){
                    sizeWithText = [labelInCell.text sizeWithFont:labelInCell.font];
                } else {
                    sizeWithText = [labelInCell.text sizeWithFont:labelInCell.font constrainedToSize:CGSizeMake(labelInCell.frame.size.width, 10000) lineBreakMode:labelInCell.lineBreakMode];

                }
                CGRect newLabelFrame = labelInCell.frame;
                newLabelFrame.origin.y = calculatedHeight;
                newLabelFrame.size.height = sizeWithText.height;

                labelInCell.frame = newLabelFrame;
                calculatedHeight += sizeWithText.height;

            } else {
                // SKip next.
                skipNext = YES;
            }
        }
    }

    CGRect cellFrame = cell.frame;
    cellFrame.size.height = calculatedHeight;
   // cell.frame = cellFrame

}

+ (CellSizeCalculator *)sharedInstance {
    if(staticInstance == NULL) {
        static dispatch_once_t onceToken;
        dispatch_once(&onceToken, ^{
                          staticInstance = [[CellSizeCalculator alloc] init];
                      });
    }

    return staticInstance;
}

@end

@implementation CSCFixedSizeElement

@synthesize verticalHeight;

@end

@implementation CSCLabelElement

@synthesize title;
@synthesize usedFont;

@end