UIWebView into a UITableViewCell with dynamic size

问题

I have UIWebView objects into multiples UITableViewCell. Each webView has a different size. Originally, all cells are the same height. Once the user touch the cell, it expand to show all webView Content.

I'm using - (void) webViewDidFinishLoad:(UIWebView *)aWebView to dynamically get the webView height, and - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath to resize the cell. However, webViewDidFinishLoad is only called after the resize method, therefore, the resize is made using old values for webView height.

I tried to call both methods manually in the desired order, but it did worked (I don't think that I should do this at all, anyway...).

Here is my code for load the web view into each cell:

    [self.webView setUserInteractionEnabled:NO];
    [self.webView loadHTMLString:finalString baseURL:nil];
    [cell addSubview:self.webView];

    cell.accessoryView = accessoryLabel;
    cell.textLabel.text = nil;

    self.selectedRowIndex = indexPath.row;

    [tableView beginUpdates];
    [tableView endUpdates];
    [tableView deselectRowAtIndexPath:indexPath animated:YES];

To dynamically get cell size:

- (void) webViewDidFinishLoad:(UIWebView *)aWebView {

CGRect frame = aWebView.frame;
frame.size.height = 1;
aWebView.frame = frame;
CGSize fittingSize = [aWebView sizeThatFits:CGSizeZero];
frame.size = fittingSize;
aWebView.frame = frame;

self.cellSize = fittingSize.height;

NSLog(@"Calling webViewDidFinishLoad. Cell size value: %lf", self.cellSize);

}

To change cell size:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:    (NSIndexPath *)indexPath {

if(indexPath.row == self.selectedRowIndex) {
  NSLog(@"Resizing cell with size: %lf", self.cellSize);
    return self.cellSize + 10;
}

return 44;
}

Here is how the output looks like:

2015-02-24 22:59:08.902 testProject[62200:2703641] Resizing cell with size: 0.000000
2015-02-24 22:59:09.064 testProject[62200:2703641] Calling webViewDidFinishLoad. Cell size value: 501.000000

Is there a way to only resize the cell after webViewDidFinishLoad has been executed?

I really appreciate any help!!

回答1:

I still don't know why this is happing but I solved it using the following approach:

I moved [tableView beginUpdates] and [tableView endUpdates] instructions to webViewDidFinishLoad method. At this way, whenever webViewDidFinishLoad be executed, it will updated the cell size correctly. Although I don't think that is the best solution, it works.

Now, my webViewDidFinishLoad method looks like this:

- (void) webViewDidFinishLoad:(UIWebView *)aWebView {

CGRect frame = aWebView.frame;
frame.size.height = 1;
aWebView.frame = frame;
CGSize fittingSize = [aWebView sizeThatFits:CGSizeZero];
frame.size = fittingSize;
aWebView.frame = frame;

self.cellSize = fittingSize.height;

[self.tableView beginUpdates];
[self.tableView endUpdates];

NSLog(@"Calling webViewDidFinishLoad. Cell size value: %lf", self.cellSize);

}

Perhaps the answer helps someone else with similar problems.

回答2:

To prevent infinite loop. the key is if you already got the height of the webview, just return it in webViewDidFinishLoad method. My webViewDidFinishLoad looks like this:

    // If the height is already exist, just return to prevent the infinite loop
    // The default height is 0.0
    if ([[self.webviewHeightDic objectForKey:[NSString stringWithFormat:@"%ld",(long)webView.tag]] floatValue] != 0.0) {

        return;
     }

    CGRect frame = webView.frame;
    frame.size.height = 1;
    webView.frame = frame;
    CGSize fittingSize = [webView sizeThatFits:CGSizeZero];
    frame.size = fittingSize;
    webView.frame = frame;

    NSLog(@"Cell height = %f ",fittingSize.height);

   // Set the height to the target webview
   [self.webviewHeightDic setObject:[NSNumber numberWithFloat:fittingSize.height]
                          forKey:[NSString stringWithFormat:@"%ld",(long)webView.tag]];

   // Refresh the tableView
   [self reloadData];

回答3:

I'm curious if it has anything to do with the order in which you do things. Can you try to do this instead:

[cell addSubview:self.webView];
self.webView.frame = ... create frame with cell width and height set to 1 ...
[self.webView loadHTMLString:finalString baseURL:nil];

回答4:

Working solution for me is to use KVO. Take care in removing the observer. Either on didEndDisplayingCell or viewWillDisappear

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
  let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
  cell.webview.addObserver(self, forKeyPath: "scrollView.contentSize", options: NSKeyValueObservingOptions.New, context: &context)
}

override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String: AnyObject]?, context: UnsafeMutablePointer<Void>) {
  if let webview = object as? UIWebView {
    let cs = webview.scrollView.contentSize
  }
}

来源：https://stackoverflow.com/questions/28709899/uiwebview-into-a-uitableviewcell-with-dynamic-size

标签

ios

objective-c

iphone

uitableview

uiwebview