使用kvo监听textView的contentSize改变
[self.textView addObserver:self forKeyPath:@"contentSize" options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld context:nil];
- (void)layoutSubviews {
CGFloat width = self.frame.size.width;
CGFloat height = self.frame.size.height;
self.leftButton.frame = CGRectMake(0, (height-50)/2, 50, 50);
self.textView.frame = CGRectMake(50, 5, width- 50-80, height-5);
self.sendButton.frame = CGRectMake(width - 80, 0, 80, height);
self.line1.frame = CGRectMake(0, 0, width, 1);
self.line2.frame = CGRectMake(self.sendButton.leftX, height *0.2, 1, height*0.6);
}
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if([keyPath isEqualToString:@"contentSize"])
{
if (self.textView.contentSize.height <= 36) {
self.frame = CGRectMake(0, SCREEN_HEIGHT-50, SCREEN_WIDTH, 50);
}else {
if (self.textView.contentSize.height <= 74) {
self.frame = CGRectMake(0, SCREEN_HEIGHT-self.textView.contentSize.height-10, SCREEN_WIDTH, self.textView.contentSize.height+10);
}else {
self.frame = CGRectMake(0, SCREEN_HEIGHT-74, SCREEN_WIDTH, 74);
}
}
}
}
