如何根据文本长度增加UITextview高度，如whatsapp

问题描述：

我已经使用websocket在我的iOS应用程序中实现了聊天功能，它对我来说很好。

I have implemented chat function in my iOS app using websocket, and it's working fine for me.

问题是我想增加UITextView的高度，并且UITableView应该根据UITextView增加的高度向上移动。任何人都可以帮助我吗？

The problem is i want to increase the height of the UITextView, and the UITableView should move up according to the height of the UITextView increase. Can anyone help me?

以下是我在我的应用程序中使用的代码：

Below is my code which i'm using in my application:

- (void)viewDidAppear:(BOOL)animated
{
    AppDelegate *appDelegate = (AppDelegate *) [[UIApplication sharedApplication]delegate];

    [super viewDidAppear:animated];


    UITapGestureRecognizer *tgr = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hideKeyboard)];
    [self.messagesTextView addGestureRecognizer:tgr];

    [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillChangeFrameNotification object:nil queue:nil usingBlock:^(NSNotification *note) {
        CGRect endFrame = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
        UIViewAnimationCurve curve = [note.userInfo[UIKeyboardAnimationCurveUserInfoKey] integerValue];
        CGFloat duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue];

        UIViewAnimationOptions options = curve << 16;

        [UIView animateWithDuration:duration delay:0.0 options:options animations:^{

            NSLog(@"frame: %@", NSStringFromCGRect(endFrame));


            CGRect frame = self.txtView.frame;
            if (isMsgLong==TRUE) {
                frame.origin.y = self.view.frame.size.height- CGRectGetHeight(self.txtView.frame)-216;

            }
            else {

                frame.origin.y = CGRectGetMinY(endFrame) - CGRectGetHeight(self.txtView.frame);
            }
            self.txtView.frame = frame;


            CGRect frame1 = self.sendButton.frame;
            frame1.origin.y = CGRectGetMinY(endFrame) - CGRectGetHeight(self.sendButton.frame);
            self.sendButton.frame = frame1;


            frame = self.messagesTextView.frame;
            frame.size.height = CGRectGetMinY(self.txtView.frame) - CGRectGetMinY(frame);
            self.messagesTextView.frame = frame;

            NSLog(@"did appear: %@", NSStringFromCGRect(self.txtView.frame));

        } completion:nil];
    }];

}

- (void)keyboardWillShow:(NSNotification *)note
{

    [UIView animateWithDuration:0.3 animations:^{
        NSDictionary *info = note.userInfo;
        NSValue *value = info[UIKeyboardFrameEndUserInfoKey];
        CGRect rawFrame = [value CGRectValue];
        CGRect keyboardFrame = [self.view convertRect:rawFrame fromView:nil];

        NSLog(@"frame: %@", NSStringFromCGRect(self.txtView.frame));

        self.txtView.transform = CGAffineTransformMakeTranslation(0, -keyboardFrame.size.height);

        self.sendButton.transform = CGAffineTransformMakeTranslation(0, -keyboardFrame.size.height);
        self.messagesTableView.contentInset=UIEdgeInsetsMake(0, 0,keyboardFrame.size.height,0);
        //keyboardFrame.size.height

        NSLog(@"frame1: %@", NSStringFromCGRect(self.txtView.frame));

        isMsgLong = FALSE;

    }];
}

- (void)keyboardWillHide:(NSNotification *)note
{
    [UIView animateWithDuration:0.3 animations:^{

        NSLog(@"frame2: %@", NSStringFromCGRect(self.txtView.frame));
        self.txtView.transform = CGAffineTransformIdentity;


        NSLog(@"frame3: %@", NSStringFromCGRect(self.txtView.frame));

        self.sendButton.transform = CGAffineTransformIdentity;
        self.messagesTableView.transform = CGAffineTransformIdentity;

        isMsgLong = TRUE;
    }];
}

-(void)textViewDidEndEditing:(UITextView *)textView
{
    self.messagesTableView.contentInset=UIEdgeInsetsMake(0, 0, 0, 0);

    self.txtView.transform = CGAffineTransformMakeTranslation(0, -216);
    self.sendButton.transform = CGAffineTransformMakeTranslation(0, -216);


    NSLog(@"frame5: %@", NSStringFromCGRect(self.txtView.frame));


    NSInteger lastSectionIndex = [self.messagesTableView numberOfSections] - 1;
    NSInteger lastRowIndex = [self.messagesTableView numberOfRowsInSection:lastSectionIndex] - 1;
    if (lastRowIndex==-1) {
        lastRowIndex=0;
    }
    NSIndexPath *pathToLastRow = [NSIndexPath indexPathForRow:lastRowIndex inSection:lastSectionIndex];

    if (lastRowIndex==0) {

    }
    else {
        [self.messagesTableView scrollToRowAtIndexPath:pathToLastRow atScrollPosition:UITableViewScrollPositionBottom animated:NO];
    //UITableViewScrollPositionMiddle
    }
}

答

这适用于iOS 6.1和iOS 7，如果您使用的是Objective C，则可以使用此代码：

This works for both iOS 6.1 and iOS 7 and if you are using Objective C you can use this Code:

- (void)textViewDidChange:(UITextView *)textView
{
    CGFloat fixedWidth = textView.frame.size.width;
    CGSize newSize = [textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)];
    CGRect newFrame = textView.frame;
    newFrame.size = CGSizeMake(fmaxf(newSize.width, fixedWidth), newSize.height);
    textView.frame = newFrame;
}

或者如果你使用Swift，请使用：

Or if you'r using Swift use this:

let fixedWidth = textView.frame.size.width
textView.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.max))
let newSize = textView.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.max))
var newFrame = textView.frame
newFrame.size = CGSize(width: max(newSize.width, fixedWidth), height: newSize.height)
textView.frame = newFrame;

如果您想要支持iOS 6.1，那么您也应该这样做：

If you want support for iOS 6.1 then you should also do this as well:

textview.scrollEnabled = NO;

如何根据文本长度增加UITextview高度，如whatsapp

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