iOS開發-簡單使用sizeThatFit計算UITextView多少行文字

    int targetTextViewWidth=424;
    NSString *msgStr=@"What are you doing?";
    UIFont *tableCellMsgFont=[UIFont systemFontOfSize:16];
    UITextView *textView = [[UITextView alloc] init];
    [textView setFont:tableCellMsgFont];
    textView.text=msgStr;
    CGSize sizeThatFitsTextView = [textView sizeThatFits:CGSizeMake(targetTextViewWidth, MAXFLOAT)];
    int lines = (int)lroundf(sizeThatFitsTextView.height) / (int)lroundf(tableCellMsgFont.lineHeight);
    NSLog(@"lines=%d",(int)lines);

注意：當行數多過10, 可能不太精準.