DZNEmptyDataSet主要是解決tableView和collectView內容為空的占位圖,自己來做會有點麻煩,使用它將會很好的解決.(肯定要有占位圖的,不然太難看).

使用很簡單.首先到github地址上下載:
https://github.com/dzenbot/DZNEmptyDataSet

//手動導入或者使用Pod都可以.

在你需要的控制器這么寫.

#import "ViewController.h"
#import"UIScrollView+EmptyDataSet.h"

@interface ViewController ()<DZNEmptyDataSetSource,DZNEmptyDataSetDelegate>
@property (nonatomic , strong ) UITableView * tableView ;

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
_tableView=[[UITableView alloc]initWithFrame:self.view.bounds];
_tableView.emptyDataSetSource=self;
_tableView.emptyDataSetDelegate=self;

// _tableView.dataSource=self;
// _tableView.delegate=self;
_tableView.tableFooterView=[UIView new];

[self.view addSubview:_tableView];

}

首先導入頭文件,其他和使用tableView一樣,遵守代理和數據源協議.
然后在數據源里設置數據,在代理里處理事件.

我現在把所有的數據源和代理發上來.首先是數據源.

@protocol DZNEmptyDataSetSource <NSObject>
@optional //可選,一個不實現都沒有關系.但是任何效果都沒有.

/**
Asks the data source for the title of the dataset.
The dataset uses a fixed font style by default, if no attributes are set. If you want a different font style, return a attributed string.

@param scrollView A scrollView subclass informing the data source.
@return An attributed string for the dataset title, combining font, text color, text pararaph style, etc.
//返回一個富文本標題
*/

• (nullable NSAttributedString *)titleForEmptyDataSet:(UIScrollView *)scrollView;

/**
Asks the data source for the description of the dataset.
The dataset uses a fixed font style by default, if no attributes are set. If you want a different font style, return a attributed string.

@param scrollView A scrollView subclass informing the data source.
@return An attributed string for the dataset description text, combining font, text color, text pararaph style, etc.
*/
//詳情文字

• (nullable NSAttributedString *)descriptionForEmptyDataSet:(UIScrollView *)scrollView;

/**
Asks the data source for the image of the dataset.

@param scrollView A scrollView subclass informing the data source.
@return An image for the dataset.
*/
//設置圖片

• (nullable UIImage *)imageForEmptyDataSet:(UIScrollView *)scrollView;

/**
Asks the data source for a tint color of the image dataset. Default is nil.

@param scrollView A scrollView subclass object informing the data source.
@return A color to tint the image of the dataset.
*/
//圖片 tint色

• (nullable UIColor *)imageTintColorForEmptyDataSet:(UIScrollView *)scrollView;

/**

• Asks the data source for the image animation of the dataset.
• @param scrollView A scrollView subclass object informing the delegate.
• @return image animation
  */
  //圖片的動畫效果

• (nullable CAAnimation *)imageAnimationForEmptyDataSet:(UIScrollView *)scrollView;

/**
Asks the data source for the title to be used for the specified button state.
The dataset uses a fixed font style by default, if no attributes are set. If you want a different font style, return a attributed string.

@param scrollView A scrollView subclass object informing the data source.
@param state The state that uses the specified title. The possible values are described in UIControlState.
@return An attributed string for the dataset button title, combining font, text color, text pararaph style, etc.

//指定button的文字
*/

• (nullable NSAttributedString *)buttonTitleForEmptyDataSet:(UIScrollView *)scrollView forState:(UIControlState)state;

/**
Asks the data source for the image to be used for the specified button state.
This method will override buttonTitleForEmptyDataSet:forState: and present the image only without any text.

@param scrollView A scrollView subclass object informing the data source.
@param state The state that uses the specified title. The possible values are described in UIControlState.
@return An image for the dataset button imageview.
*/
//按鈕圖片(設置了將不會有按鈕文本)

• (nullable UIImage *)buttonImageForEmptyDataSet:(UIScrollView *)scrollView forState:(UIControlState)state;

/**
Asks the data source for a background image to be used for the specified button state.
There is no default style for this call.

@param scrollView A scrollView subclass informing the data source.
@param state The state that uses the specified image. The values are described in UIControlState.
@return An attributed string for the dataset button title, combining font, text color, text pararaph style, etc.
*/
//設置按鈕的背景圖片

• (nullable UIImage *)buttonBackgroundImageForEmptyDataSet:(UIScrollView *)scrollView forState:(UIControlState)state;

/**
Asks the data source for the background color of the dataset. Default is clear color.

@param scrollView A scrollView subclass object informing the data source.
@return A color to be applied to the dataset background view.
*/
//設置背景顏色

• (nullable UIColor *)backgroundColorForEmptyDataSet:(UIScrollView *)scrollView;

/**
//自定義view
Asks the data source for a custom view to be displayed instead of the default views such as labels, imageview and button. Default is nil.
Use this method to show an activity view indicator for loading feedback, or for complete custom empty data set.
Returning a custom view will ignore -offsetForEmptyDataSet and -spaceHeightForEmptyDataSet configurations.
返回的view將不再管-offsetForEmptyDataSet and -spaceHeightForEmptyDataSet configurations里面的設置了.
@param scrollView A scrollView subclass object informing the delegate.
@return The custom view.
*/

• (nullable UIView *)customViewForEmptyDataSet:(UIScrollView *)scrollView;

/**
Asks the data source for a offset for vertical and horizontal alignment of the content. Default is CGPointZero.

@param scrollView A scrollView subclass object informing the delegate.
@return The offset for vertical and horizontal alignment.
*/
//設置垂直和水平對齊間距

• (CGPoint)offsetForEmptyDataSet:(UIScrollView *)scrollView DZNEmptyDataSetDeprecated(-verticalOffsetForEmptyDataSet:);
• (CGFloat)verticalOffsetForEmptyDataSet:(UIScrollView *)scrollView;

/**
Asks the data source for a vertical space between elements. Default is 11 pts.

@param scrollView A scrollView subclass object informing the delegate.
@return The space height between elements.
*/
//元素與元素之間的垂直空白間距.

• (CGFloat)spaceHeightForEmptyDataSet:(UIScrollView *)scrollView;

@end

/////////////////////////////////

講完了datesource,那就來看delegate了.

@protocol DZNEmptyDataSetDelegate <NSObject>

@optional

/**
Asks the delegate to know if the empty dataset should fade in when displayed. Default is YES.

@param scrollView A scrollView subclass object informing the delegate.
@return YES if the empty dataset should fade in.
*/
//是否漸進顯示view,在顯示之前你可以做你想要做的事.

• (BOOL)emptyDataSetShouldFadeIn:(UIScrollView *)scrollView;

/**
Asks the delegate to know if the empty dataset should still be displayed when the amount of items is more than 0. Default is NO

@param scrollView A scrollView subclass object informing the delegate.
@return YES if empty dataset should be forced to display
*/
//當視圖有數據了是否繼續顯示占位圖,默認是不顯示的.

• (BOOL)emptyDataSetShouldBeForcedToDisplay:(UIScrollView *)scrollView;

/**
Asks the delegate to know if the empty dataset should be rendered and displayed. Default is YES.

@param scrollView A scrollView subclass object informing the delegate.
@return YES if the empty dataset should show.
*/
//是否占位圖應該被渲染和重繪.

• (BOOL)emptyDataSetShouldDisplay:(UIScrollView *)scrollView;

/**
Asks the delegate for touch permission. Default is YES.

@param scrollView A scrollView subclass object informing the delegate.
@return YES if the empty dataset receives touch gestures.
*/
//是否一直允許觸摸

• (BOOL)emptyDataSetShouldAllowTouch:(UIScrollView *)scrollView;

/**
Asks the delegate for scroll permission. Default is NO.

@param scrollView A scrollView subclass object informing the delegate.
@return YES if the empty dataset is allowed to be scrollable.
*/
//是否允許滾動.

• (BOOL)emptyDataSetShouldAllowScroll:(UIScrollView *)scrollView;

/**
Asks the delegate for image view animation permission. Default is NO.
Make sure to return a valid CAAnimation object from imageAnimationForEmptyDataSet:

@param scrollView A scrollView subclass object informing the delegate.
@return YES if the empty dataset is allowed to animate
*/
//是否允許動畫.

• (BOOL)emptyDataSetShouldAnimateImageView:(UIScrollView *)scrollView;

/**
Tells the delegate that the empty dataset view was tapped.
Use this method either to resignFirstResponder of a textfield or searchBar.

@param scrollView A scrollView subclass informing the delegate.
*/
//空白部分被點擊了

• (void)emptyDataSetDidTapView:(UIScrollView *)scrollView DZNEmptyDataSetDeprecated(-emptyDataSet:didTapView:);

/**
Tells the delegate that the action button was tapped.

@param scrollView A scrollView subclass informing the delegate.
*/
//按鈕被點擊了 .

• (void)emptyDataSetDidTapButton:(UIScrollView *)scrollView DZNEmptyDataSetDeprecated(-emptyDataSet:didTapButton:);

/**
Tells the delegate that the empty dataset view was tapped.
Use this method either to resignFirstResponder of a textfield or searchBar.

@param scrollView A scrollView subclass informing the delegate.
@param view the view tapped by the user
*/
//指定的view被點擊了.

• (void)emptyDataSet:(UIScrollView *)scrollView didTapView:(UIView *)view;

/**
Tells the delegate that the action button was tapped.

@param scrollView A scrollView subclass informing the delegate.
@param button the button tapped by the user
*/
//指定的按鈕被點擊了

• (void)emptyDataSet:(UIScrollView *)scrollView didTapButton:(UIButton *)button;

/**
Tells the delegate that the empty data set will appear.

@param scrollView A scrollView subclass informing the delegate.
*/
//占位圖即將顯示

• (void)emptyDataSetWillAppear:(UIScrollView *)scrollView;

/**
Tells the delegate that the empty data set did appear.

@param scrollView A scrollView subclass informing the delegate.
*/
//占位圖已經顯示

• (void)emptyDataSetDidAppear:(UIScrollView *)scrollView;

/**
Tells the delegate that the empty data set will disappear.

@param scrollView A scrollView subclass informing the delegate.
*/
//占位圖即將消失

• (void)emptyDataSetWillDisappear:(UIScrollView *)scrollView;

/**
Tells the delegate that the empty data set did disappear.

@param scrollView A scrollView subclass informing the delegate.
*/
//占位圖已經消失

• (void)emptyDataSetDidDisappear:(UIScrollView *)scrollView;

@end