在iOS中使用UIWebview计算UITableViewCell高度

Question

I am creating a table based application where need to display one UIWebView for each table cell. I have tried by keeping a NSMutableArray of height for each cell in my table, but it's not working.

here is my code :

- (void)webViewDidFinishLoad:(UIWebView *)aWebView
{
    aWebView.scrollView.scrollEnabled = NO;
    CGRect frame = aWebView.frame;
    frame.size.height = 1;
    aWebView.frame = frame;
    CGSize fittingSize = [aWebView sizeThatFits:CGSizeZero];
    frame.size = fittingSize;
    aWebView.frame = frame;

    if (arrayRowHeights.count == 0 || arrayRowHeights == nil) {

        arrayRowHeights = [[NSMutableArray alloc] init];
        [arrayRowHeights addObject:[NSString stringWithFormat:@"%f", fittingSize.height]];
    }
    else{
        [arrayRowHeights addObject:[NSString stringWithFormat:@"%f", fittingSize.height]];

        if (arrayRowHeights.count == aWebView.tag) {
            [tblEventInfo reloadData];
        }
    }
}

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return [arrayEventInfo count];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return 1;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return [[arrayRowHeights objectAtIndex:indexPath.section] floatValue];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if(cell == nil)
    {
        EventInfoDetail *event = [[EventInfoDetail alloc] init];
        event = [arrayEventInfo objectAtIndex:indexPath.section];

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

        webViewHTML = [[UIWebView alloc]init];
        webViewHTML.delegate = self;
        webViewHTML.tag = arrayEventInfo.count;
        webViewHTML.backgroundColor = [UIColor clearColor];
        webViewHTML.opaque = NO;
        webViewHTML.userInteractionEnabled = NO;

        if (event.d_description == (NSString *)[NSNull null]){
            [webViewHTML loadHTMLString:@"" baseURL: nil];
        }
        else{
            [webViewHTML loadHTMLString:event.d_description baseURL: nil];
        }

        webViewHTML.frame = CGRectMake(0, 0, cell.frame.size.width, cell.frame.size.height);

        [cell.contentView addSubview:webViewHTML];
    }

    return cell;
}

My problem is I am not able to set the the height of the cell properly, can anyone please figure out where is my mistake on this given code. Thanks!

Answer 1

Your webViewDidFinishLoad for each cell will get called only after the tablecell is loaded i,e; So the sequence calls will be heightForRowAtIndexPath -> cellForRowAtIndexPath -> webViewDidFinishLoad . So you will never be able to set the height before cell loads. After webView is loaded try calling

- (void)webViewDidFinishLoad:(UIWebView *)aWebView {[tableView reloadRowsAtIndexPaths:[tableView indexPathsForVisibleRows] withRowAnimation:UITableViewRowAnimationNone];}

which will call heightForRowAtIndexPath again and try to set it again. But the height will increase at runtime .You should customize that event

Answer 2

Initialize your arrayRowHeights as NSMutableArray beforehand(in viewDidLoad method for instance) with the same capacity as arrayEventInfo.Change your webView delegate method to this one

- (void)webViewDidFinishLoad:(UIWebView *)aWebView {
    CGFloat height = aWebView.scrollView.contentSize.height;
    if (height != [[arrayRowHeights objectAtIndex: aWebView.tag] floatValue]) {
       [arrayRowHeights insertObject:[NSNumber numberWithFloat: height] atIndex: aWebView.tag];
       [tblEventInfo reloadRowsAtIndexPaths:@[[NSIndexPath indexPathForItem:0 inSection:aWebView.tag]] withRowAnimation:UITableViewRowAnimationNone];
    }
}

In method:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

Change line

webViewHTML.tag = arrayEventInfo.count;

with line

webViewHTML.tag = indexPath.section;