Question

当用户在UITableView中向下滚动时，我们如何跟踪每个UITableViewCell视图？用户需要查看单元格一段时间（1秒）才能将其计为视图。

下面的基本跟踪无法给出准确的结果，因为用户可以快速滚动，不会被视为单元格视图。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object {
    [self logCellView:indexPath objectId:object.objectId];
}

或

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
        [self logCellView:indexPath objectId:object.objectId];
}

然后

-(void)logCellView:(NSIndexPath *)indexPath objectId:(NSString *)objectId {
    // Log the cell view with any analytics tool here
}

Answer 1

首先是自定义单元格：

#import <UIKit/UIKit.h>

@interface MyCell : UITableViewCell

@property (assign, nonatomic) NSTimeInterval time;

@end

主要代码：

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    MyCell *cell = [tableView dequeueReusableCellWithIdentifier:@"MyCell" forIndexPath:indexPath];
    return cell;
}

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
    MyCell *myCell = (MyCell *)cell;
    myCell.time = [[NSDate date] timeIntervalSince1970];
}

-(void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
    MyCell *myCell = (MyCell *)cell;
    NSTimeInterval startTime = myCell.time;
    NSTimeInterval currentTime = [[NSDate date] timeIntervalSince1970];
    if (currentTime - startTime >= 1) {
        NSLog(@"Logging.. %i.Row Display Time = %f", indexPath.row, currentTime-startTime);
    }
}

Answer 2

一种解决方案可能在下面，但有一个更稳定的＆amp;安全的方式？

-(void)logCellView:(NSIndexPath *)indexPath object:(NSString *)object {
    // Set the timer to log the view since we don't want to log fast scrolls
    if (indexPath.row >= [logViewTimers count] && object) {
        [logViewTimers insertObject:[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(logCellViewQuery:) userInfo:object repeats:NO] atIndex:indexPath.row];
    } else {
        // Cell is viewed again, set a longer interval
        [logViewTimers replaceObjectAtIndex:indexPath.row withObject:[NSTimer scheduledTimerWithTimeInterval:3 target:self selector:@selector(logCellViewQuery:) userInfo:object repeats:NO]];
    }
}

-(void)logCellViewQuery:(NSTimer*)theTimer {
     NSLog (@"Will save the log for: %@", (NSString*)[theTimer userInfo]);
    // Query here (hidden for security)
}

- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"Gone indexPath: %ld",(long)indexPath.row);
    // Kill the timer to log the view since user scrolled fast
    if (indexPath.row < [logViewTimers count]) {
        if (((NSTimer*)[logViewTimers objectAtIndex:indexPath.row])) {
            [((NSTimer*)[logViewTimers objectAtIndex:indexPath.row]) invalidate];
        }
    }
}

如何在用户滚动时跟踪和记录UITableViewCell视图？

2 个答案: