關於iOS中的textView

1.關於實現textView的提示文字，代碼片段如下：

－ 1.初始化

self.textView = [[UITextView alloc] initWithFrame:CGRectMake(10, 74, KscreenWidth - 20, 200)];
    self.textView.delegate = self;
    [self.view addSubview:self.textView];

    self.placeholderLabel = [[UILabel alloc]initWithFrame:CGRectMake(3, 3, 200, 20)];
    self.placeholderLabel.enabled = NO;
    self.placeholderLabel.text = @"請輸入您寶貴的意見或是建議";
    self.placeholderLabel.font =  [UIFont systemFontOfSize:15];
    self.placeholderLabel.textColor = [UIColor lightGrayColor];
    [self.textView addSubview:self.placeholderLabel];

－2添加代理方法，當開始輸入時隱藏提示，刪除到字節長度爲0時繼續提示

 - (void) textViewDidChange:(UITextView *)textView{
    if ([textView.text length] == 0) {
        [self.placeholderLabel setHidden:NO];
    }else{
        [self.placeholderLabel setHidden:YES];
    }
}

不過這樣做完還不夠，此時textview的光標位置會處於中間靠左，這是因爲導航欄的偏移問題，所以還要加上一句代碼

self.automaticallyAdjustsScrollViewInsets = NO;

大功告成