UITextView自动滚动的解决方案

思路：UIView加载完成3后，用NSTimer结合setContentOffset将UITextView向下滚动1像素。在滚动到底部的时候停止NSTimer。每当手动滚动UITextView前销毁NSTimer，滚动后重新创建NSTimer。

NSTimer  *timer;
- ( void )viewDidLoad {
    [ self  performSelector: @selector (resetText) withObject: nil  afterDelay:3.0f];
}

- ( void )resetText {
    [timer invalidate];
    timer = nil ;
    timer = [ NSTimer  scheduledTimerWithTimeInterval: 0.06
                                             target: self
                                           selector: @selector (onTick:)
                                           userInfo: nil  repeats: YES ];
}

- ( void )scrollViewWillBeginDragging:(UIScrollView *)scrollView {
    [timer invalidate];
    timer = nil ;
    NSLog (@ "scrollViewWillBeginDragging" );
    [ self  performSelector: @selector (resetText) withObject: nil  afterDelay:3.0f];
}
- ( void ) onTick:( NSTimer *)theTimer {
    CGPoint pt = [textView contentOffset];
    CGFloat n = pt.y + 1;
    [textView setContentOffset:CGPointMake(pt.x, n)];
    if  (n> (textView.contentSize.height-textView.bounds.size.height)) {
        [theTimer invalidate];
        theTimer = nil ;
        [timer invalidate];
        timer = nil ;
    }
}

最后 不要忘了实现

UIScrollViewDelegate