最好先计算高度，不要在方法中包含高度计算部分：
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
最好用方法来计算：
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
因为你从 json 获取数据，所以你很容易计算
在“heightForRowAtIndexPath”方法中。
以下代码将给出计算文本高度的示例，根据您的要求更改它。
希望这对你有帮助:)
// i am using an array
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIFont *labelFont = [UIFont fontWithName:@"Noteworthy-Bold" size:20];
NSDictionary *arialdict = [NSDictionary dictionaryWithObject:labelFont forKey:NSFontAttributeName];
NSMutableAttributedString *message = [[NSMutableAttributedString alloc] initWithString:@"this is just the sample example of how to calculate the dynamic height for tableview cell which is of around 7 to 8 lines. you will need to set the height of this string first, not seems to be calculated in cellForRowAtIndexPath method." attributes:arialdict];
array = [NSMutableArray arrayWithObjects:message, nil];
NSMutableAttributedString *message_1 = [[NSMutableAttributedString alloc] initWithString:@"you will need to set the height of this string first, not seems to be calculated in cellForRowAtIndexPath method." attributes:arialdict];
[array addObject:message_1];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 2;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 2;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *Cell = [self.aTableView dequeueReusableCellWithIdentifier:@"cell"];
if(Cell == nil)
{
Cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];
}
//dont include the height calculation part hear, becz heights are already set for all the cell
[Cell.textLabel sizeToFit];
Cell.textLabel.attributedText = [array objectAtIndex:indexPath.row]; // dont calculate height hear it will be called after "heightForRowAtIndexPath" method
Cell.textLabel.numberOfLines = 8;
return Cell;
}
// put ur height calculation method i took some hardcoded values change it :)
-(float)height :(NSMutableAttributedString*)string
{
/*
NSString *stringToSize = [NSString stringWithFormat:@"%@", string];
// CGSize constraint = CGSizeMake(LABEL_WIDTH - (LABEL_MARGIN *2), 2000.f);
CGSize maxSize = CGSizeMake(280, MAXFLOAT);//set max height //set the constant width, hear MAXFLOAT gives the maximum height
CGSize size = [stringToSize sizeWithFont:[UIFont systemFontOfSize:20.0f] constrainedToSize:maxSize lineBreakMode:NSLineBreakByWordWrapping];
return size.height; //finally u get the correct height
*/
//commenting the above code because "sizeWithFont: constrainedToSize:maxSize: lineBreakMode: " has been deprecated to avoid above code use below
NSAttributedString *attributedText = string;
CGRect rect = [attributedText boundingRectWithSize:(CGSize){225, MAXFLOAT}
options:NSStringDrawingUsesLineFragmentOrigin
context:nil];//you need to specify the some width, height will be calculated
CGSize requiredSize = rect.size;
return requiredSize.height; //finally u return your height
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
//whatever the height u need to calculate calculate hear only
CGFloat heightOfcell = [self height:[array objectAtIndex:indexPath.row]];
NSLog(@"%f",heightOfcell);
return heightOfcell;
}
希望这对你有帮助:)
For SWIFT version
class ViewController: UIViewController,UITableViewDataSource,UITableViewDelegate
{
var messageArray:[String] = [] //array to holde the response form son for example
override func viewDidLoad()
{
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
messageArray = ["One of the most interesting features of Newsstand is that once an asset downloading has started it will continue even if the application is suspended (that is: not running but still in memory) or it is terminated. Of course during while your app is suspended it will not receive any status update but it will be woken up in the background",
"In case that app has been terminated while downloading was in progress, the situation is different. Infact in the event of a finished downloading the app can not be simply woken up and the connection delegate finish download method called, as when an app is terminated its App delegate object doesn’t exist anymore. In such case the system will relaunch the app in the background.",
" If defined, this key will contain the array of all asset identifiers that caused the launch. From my tests it doesn’t seem this check is really required if you reconnect the pending downloading as explained in the next paragraph.",
]
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int
{
return 1;
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return messageArray.count;
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
var cell:UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("CELL") as? UITableViewCell;
if(cell == nil)
{
cell = UITableViewCell(style:UITableViewCellStyle.Default, reuseIdentifier: "CELL")
cell?.selectionStyle = UITableViewCellSelectionStyle.None
}
cell?.textLabel.font = UIFont.systemFontOfSize(15.0)
cell?.textLabel.sizeToFit()
cell?.textLabel.text = messageArray[indexPath.row]
cell?.textLabel.numberOfLines = 0
return cell!;
}
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat
{
var height:CGFloat = self.calculateHeightForString(messageArray[indexPath.row])
return height + 70.0
}
func calculateHeightForString(inString:String) -> CGFloat
{
var messageString = inString
var attributes = [UIFont(): UIFont.systemFontOfSize(15.0)]
var attrString:NSAttributedString? = NSAttributedString(string: messageString, attributes: attributes)
var rect:CGRect = attrString!.boundingRectWithSize(CGSizeMake(300.0,CGFloat.max), options: NSStringDrawingOptions.UsesLineFragmentOrigin, context:nil )
var requredSize:CGRect = rect
return requredSize.height //to include button's in your tableview
}
}
