设置UITextView Padding

gistfile1.m

//设置padding
-(void) padding{
    //padding大小（top,left,bottom,right)
    UIEdgeInsets padding = UIEdgeInsetsMake(0, 15, 0, 15);
    _textView.contentInset = padding;
    
    CGRect frame = _textView.frame;
    
    // must change frame before bounds because the text wrap is reformatted based on frame, don't include the top and bottom insets
    CGRect insetFrame = UIEdgeInsetsInsetRect(frame, UIEdgeInsetsMake(0, padding.left, 0, padding.right));
    // offset frame back to original x
    CGFloat offsetX = frame.origin.x - (insetFrame.origin.x - ( padding.left + padding.right ) / 2);
    insetFrame = CGRectApplyAffineTransform(insetFrame, CGAffineTransformMakeTranslation(offsetX, 0));
     _textView.frame = insetFrame;
    
    _textView.bounds = UIEdgeInsetsInsetRect(_textView.bounds, UIEdgeInsetsMake(0, -padding.left, 0, -padding.right));
    [_textView scrollRectToVisible:CGRectMake(0,0,1,1) animated:NO];
}