textView高度随文字内容变化 聊天

1.

#define HEIGHT [UIScreen mainScreen].bounds.size.height

#define WIDTH [UIScreen mainScreen].bounds.size.width

#define ChatHeight 45.0

 <UITextViewDelegate> //设置代理

@property(strong, nonatomic) UIView * sendBackView;

@property(strong, nonatomic) UITextView * sendTextView;

2.//初始化ui

self.sendBackView = [[UIView alloc] initWithFrame:CGRectMake(0, 100, WIDTH, ChatHeight)];

    self.sendBackView.backgroundColor = [UIColor colorWithRed:240/255.0 green:240/255.0 blue:240/255.0 alpha:1.0];

    [self.view addSubview:self.sendBackView];

    //    float heightView = self.sendBackView.frame.size.height;

    

    self.sendTextView = [[UITextView alloc] initWithFrame:CGRectMake(10, 5, WIDTH - 10 - 90, 35)];

    //    self.sendTextView.backgroundColor = [UIColor lightGrayColor];

    self.sendTextView.returnKeyType = UIReturnKeySend;

    self.sendTextView.font = [UIFont systemFontOfSize:17];

    self.sendTextView.editable = YES;

    self.sendTextView.delegate = self;

    [self.sendBackView addSubview:self.sendTextView];

3.delegate

// 这是一种很好的键盘下移方式

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text

{

    if ([text isEqualToString:@"\n"]) {

        return NO;

    }

    return YES;

}

 

- (void)textViewDidChange:(UITextView *)textView

{

    // 随机改变其高度

    float textHeight = [self heightForString:textView.text fontSize:16 andWidth:textView.frame.size.width];

    _sendTextViewHeight = textHeight;

    self.sendTextView.frame = CGRectMake(10, 5, WIDTH - 10 - 90, _sendTextViewHeight);

    self.sendBackView.frame = CGRectMake(0, HEIGHT -  _sendBackViewHeight - _sendTextViewHeight - 10, WIDTH, _sendTextViewHeight + 10);

}

 

- (float) heightForString:(NSString *)value fontSize:(float)fontSize andWidth:(float)width

{

    UITextView *detailTextView = [[UITextView alloc]initWithFrame:CGRectMake(0, 0, width, 0)];

    detailTextView.font = [UIFont systemFontOfSize:fontSize];

    detailTextView.text = value;

    CGSize deSize = [detailTextView sizeThatFits:CGSizeMake(width,CGFLOAT_MAX)];

    return deSize.height;

}