ios - cordova / ios / 混合应用程序 - UITableView 加载项目不正确且无序

问题描述

我的UITableView. 它正在加载行0, 1, 2- 但是当它到达 row 时3，它会加载 row 4，然后对于 row 4，它会0再次加载 row ，所以它是这样的：

表中的行：

它显然应该0, 1, 2, 3, 4按顺序进行。这是我的代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"cellForRowAtIndexPath getting called - row: %li", indexPath.row);

    [self.items enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"items at every cell entry: %@", [obj valueForKey:@"item"]);
    }];

    //UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell1" forIndexPath:indexPath];
    //NSLog(@"indexPath.row: %li, %@", (long)indexPath.row, [self.items objectAtIndex:indexPath.row]);

    PoolsTableViewCell *cell = (PoolsTableViewCell*)[tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

    if(cell.cellLeftImageView.image == nil) {

        NSInteger left = 2*indexPath.row;
        NSLog(@"left: %li", (long)left);

        NSObject* obj = (NSObject*)[self.items objectAtIndex:left];

        cell.cellLeftViewLabel.text = [obj valueForKey:@"item"];

        NSString *ImageURL = [obj valueForKey:@"downloadURL"];
        NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:ImageURL]];
        cell.cellLeftImageView.image = [UIImage imageWithData:imageData];

        NSInteger right = (2*indexPath.row)+1;
        NSLog(@"right: %li", (long)right);

        if(right < [self.items count]) {
            NSLog(@"inside right < self.items count conditional");
            NSObject* objPlus = (NSObject*)[self.items objectAtIndex:right];

            cell.cellRightViewLabel.text = [objPlus valueForKey:@"item"];

            NSString *secondImageURL = [objPlus valueForKey:@"downloadURL"];
            NSData *secondImageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:secondImageURL]];
            cell.cellRightImageView.image = [UIImage imageWithData:secondImageData];
        }
    }

    return cell;
}

我有这段代码，每次cellForRowAtIndex调用时都会记录所有项目：

[self.items enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, 
    BOOL * _Nonnull stop) {
    NSLog(@"items at every cell entry: %@", [obj valueForKey:@"item"]);
}];

我从self.items每一行加载 2 个项目（每行基本上有 2 列）。控制台输出对于每次调用都是正确的cellForRowAtIndexPath- 所以self.items永远不应该乱序引用，但它是 - 这是UITableView加载时我的控制台输出的一个示例：

2019-02-02 22:01:30.121975-0500 HybridPool[1720:534623] cellForRowAtIndexPath getting called - row: 0
2019-02-02 22:01:30.122149-0500 HybridPool[1720:534623] items at ever cell entry: Table
2019-02-02 22:01:30.122263-0500 HybridPool[1720:534623] items at ever cell entry: Cord
2019-02-02 22:01:30.122373-0500 HybridPool[1720:534623] items at ever cell entry: Keys
2019-02-02 22:01:30.122645-0500 HybridPool[1720:534623] items at ever cell entry: Hshhdhdbd
2019-02-02 22:01:30.122769-0500 HybridPool[1720:534623] items at ever cell entry: Jhghhvhh
2019-02-02 22:01:30.122947-0500 HybridPool[1720:534623] items at ever cell entry: Book
2019-02-02 22:01:30.123054-0500 HybridPool[1720:534623] items at ever cell entry: Njhhnn
2019-02-02 22:01:30.123160-0500 HybridPool[1720:534623] items at ever cell entry: Tv
2019-02-02 22:01:30.123260-0500 HybridPool[1720:534623] items at ever cell entry: 9th item
2019-02-02 22:01:30.129478-0500 HybridPool[1720:534623] left: 0
2019-02-02 22:01:31.024184-0500 HybridPool[1720:534623] right: 1
2019-02-02 22:01:31.024302-0500 HybridPool[1720:534623] inside right < self.items count conditional
2019-02-02 22:01:31.719052-0500 HybridPool[1720:534623] cellForRowAtIndexPath getting called - row: 1
2019-02-02 22:01:31.719252-0500 HybridPool[1720:534623] items at ever cell entry: Table
2019-02-02 22:01:31.719374-0500 HybridPool[1720:534623] items at ever cell entry: Cord
2019-02-02 22:01:31.719481-0500 HybridPool[1720:534623] items at ever cell entry: Keys
2019-02-02 22:01:31.719584-0500 HybridPool[1720:534623] items at ever cell entry: Hshhdhdbd
2019-02-02 22:01:31.719687-0500 HybridPool[1720:534623] items at ever cell entry: Jhghhvhh
2019-02-02 22:01:31.719785-0500 HybridPool[1720:534623] items at ever cell entry: Book
2019-02-02 22:01:31.719884-0500 HybridPool[1720:534623] items at ever cell entry: Njhhnn
2019-02-02 22:01:31.720048-0500 HybridPool[1720:534623] items at ever cell entry: Tv
2019-02-02 22:01:31.720170-0500 HybridPool[1720:534623] items at ever cell entry: 9th item
2019-02-02 22:01:31.724875-0500 HybridPool[1720:534623] left: 2
2019-02-02 22:01:32.340747-0500 HybridPool[1720:534623] right: 3
2019-02-02 22:01:32.340969-0500 HybridPool[1720:534623] inside right < self.items count conditional
2019-02-02 22:01:32.776360-0500 HybridPool[1720:534623] cellForRowAtIndexPath getting called - row: 2
2019-02-02 22:01:32.776572-0500 HybridPool[1720:534623] items at ever cell entry: Table
2019-02-02 22:01:32.776685-0500 HybridPool[1720:534623] items at ever cell entry: Cord
2019-02-02 22:01:32.776877-0500 HybridPool[1720:534623] items at ever cell entry: Keys
2019-02-02 22:01:32.777113-0500 HybridPool[1720:534623] items at ever cell entry: Hshhdhdbd
2019-02-02 22:01:32.777244-0500 HybridPool[1720:534623] items at ever cell entry: Jhghhvhh
2019-02-02 22:01:32.777344-0500 HybridPool[1720:534623] items at ever cell entry: Book
2019-02-02 22:01:32.777443-0500 HybridPool[1720:534623] items at ever cell entry: Njhhnn
2019-02-02 22:01:32.777542-0500 HybridPool[1720:534623] items at ever cell entry: Tv
2019-02-02 22:01:32.777641-0500 HybridPool[1720:534623] items at ever cell entry: 9th item
2019-02-02 22:01:32.782148-0500 HybridPool[1720:534623] left: 4
2019-02-02 22:01:33.383439-0500 HybridPool[1720:534623] right: 5
2019-02-02 22:01:33.383649-0500 HybridPool[1720:534623] inside right < self.items count conditional
2019-02-02 22:01:34.534761-0500 HybridPool[1720:534623] cellForRowAtIndexPath getting called - row: 3
2019-02-02 22:01:34.534980-0500 HybridPool[1720:534623] items at ever cell entry: Table
2019-02-02 22:01:34.535099-0500 HybridPool[1720:534623] items at ever cell entry: Cord
2019-02-02 22:01:34.535206-0500 HybridPool[1720:534623] items at ever cell entry: Keys
2019-02-02 22:01:34.535310-0500 HybridPool[1720:534623] items at ever cell entry: Hshhdhdbd
2019-02-02 22:01:34.535412-0500 HybridPool[1720:534623] items at ever cell entry: Jhghhvhh
2019-02-02 22:01:34.535666-0500 HybridPool[1720:534623] items at ever cell entry: Book
2019-02-02 22:01:34.535787-0500 HybridPool[1720:534623] items at ever cell entry: Njhhnn
2019-02-02 22:01:34.535895-0500 HybridPool[1720:534623] items at ever cell entry: Tv
2019-02-02 22:01:34.536022-0500 HybridPool[1720:534623] items at ever cell entry: 9th item
2019-02-02 22:01:34.540261-0500 HybridPool[1720:534623] left: 6
2019-02-02 22:01:35.090979-0500 HybridPool[1720:534623] right: 7
2019-02-02 22:01:35.091111-0500 HybridPool[1720:534623] inside right < self.items count conditional
2019-02-02 22:01:35.886101-0500 HybridPool[1720:534623] cellForRowAtIndexPath getting called - row: 4
2019-02-02 22:01:35.886329-0500 HybridPool[1720:534623] items at ever cell entry: Table
2019-02-02 22:01:35.886446-0500 HybridPool[1720:534623] items at ever cell entry: Cord
2019-02-02 22:01:35.886554-0500 HybridPool[1720:534623] items at ever cell entry: Keys
2019-02-02 22:01:35.886658-0500 HybridPool[1720:534623] items at ever cell entry: Hshhdhdbd
2019-02-02 22:01:35.886978-0500 HybridPool[1720:534623] items at ever cell entry: Jhghhvhh
2019-02-02 22:01:35.887082-0500 HybridPool[1720:534623] items at ever cell entry: Book
2019-02-02 22:01:35.887184-0500 HybridPool[1720:534623] items at ever cell entry: Njhhnn
2019-02-02 22:01:35.887311-0500 HybridPool[1720:534623] items at ever cell entry: Tv
2019-02-02 22:01:35.887449-0500 HybridPool[1720:534623] items at ever cell entry: 9th item
2019-02-02 22:01:35.891688-0500 HybridPool[1720:534623] left: 8
2019-02-02 22:01:36.660758-0500 HybridPool[1720:534623] right: 9
2019-02-02 22:01:36.931630-0500 HybridPool[1720:534623] Item added! pool

为了澄清self.items我在表中看到的项目名称，如下所示：

**Row 0:**
Table, Cord
**Row 1:**
Keys, Hshhdhdbd
**Row 2:**
Jhghhvhh, Book
**Row 3:**
9th item, (blank - because there are only 9 items - not an even 10) --> this row should be last!
**Row 4:**
Table, Cord <- this is the first row again, this should be what is in **Row 3** - 9th item, blank.

我也应该显示这个，以防我在这里做错了什么：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    if([self.items count] % 2 != 0) {
        return ([self.items count] + 1) / 2;
    }
    else {
        return [self.items count] / 2;
    }
}

对于上面，因为我将两个项目加载到行中，所以我处理有偶数项目的情况（这只是除以[self.items count]。2对于奇数数量self.items，我1在除以之前添加，2以便有可用的行最后一项（然后该行中的一个位置留空）。这对我来说似乎是正确的，但也许我在这里遗漏了一些棘手的错误？

从控制台输出来看，我不知道为什么这些行被乱序加载，或者为什么Row 0重复 for Row 4，请帮忙，谢谢！

更新

得到相同的结果：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"cellForRowAtIndexPath getting called - row: %li", indexPath.row);

    [self.leftItems enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"leftItem: %@", [obj valueForKey:@"item"]);
    }];

    [self.rightItems enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"rightItem: %@", [obj valueForKey:@"item"]);
    }];

    //UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell1" forIndexPath:indexPath];
    //NSLog(@"indexPath.row: %li, %@", (long)indexPath.row, [self.items objectAtIndex:indexPath.row]);

    PoolsTableViewCell *cell = (PoolsTableViewCell*)[tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

    if(cell.cellLeftImageView.image == nil) { //Equivalent to cell == nil
        NSObject* leftObj = [self.leftItems objectAtIndex:indexPath.row];
        NSObject* rightObj = [self.rightItems objectAtIndex:indexPath.row];

        cell.cellLeftViewLabel.text = [leftObj valueForKey:@"item"];

        NSString *ImageURL = [leftObj valueForKey:@"downloadURL"];
        NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:ImageURL]];
        cell.cellLeftImageView.image = [UIImage imageWithData:imageData];

        if(![rightObj isEqual:[NSNull null]]) {
            cell.cellRightViewLabel.text = [rightObj valueForKey:@"item"];

            NSString *secondImageURL = [rightObj valueForKey:@"downloadURL"];
            NSData *secondImageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:secondImageURL]];
            cell.cellRightImageView.image = [UIImage imageWithData:secondImageData];
        }
        else {
            cell.cellRightViewLabel.text = @"";
            cell.cellRightImageView.image = nil;
        }
    }

    return cell;
}

控制台输出：

2019-02-03 11:32:50.583214-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 0
2019-02-03 11:32:50.583377-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:32:50.583486-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:32:50.583605-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:32:50.583997-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:32:50.584116-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:32:50.584224-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:32:50.584328-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:32:50.584429-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:32:50.584528-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:32:50.584771-0500 HybridPool[1827:594545] rightItem: <null>
2019-02-03 11:32:54.647304-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 1
2019-02-03 11:32:54.647551-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:32:54.647666-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:32:54.647773-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:32:54.647876-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:32:54.647992-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:32:54.648102-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:32:54.648199-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:32:54.648403-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:32:54.648519-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:32:54.648769-0500 HybridPool[1827:594545] rightItem: <null>
2019-02-03 11:32:56.447403-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 2
2019-02-03 11:32:56.447610-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:32:56.447724-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:32:56.447829-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:32:56.447931-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:32:56.448151-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:32:56.448281-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:32:56.448389-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:32:56.448490-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:32:56.448589-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:32:56.448689-0500 HybridPool[1827:594545] rightItem: <null>
2019-02-03 11:32:57.981261-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 3
2019-02-03 11:32:57.981471-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:32:57.981625-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:32:57.981745-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:32:57.981874-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:32:57.982081-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:32:57.982214-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:32:57.982315-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:32:57.982441-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:32:57.982539-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:32:57.982638-0500 HybridPool[1827:594545] rightItem: <null>
2019-02-03 11:33:00.735076-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 4
2019-02-03 11:33:00.735252-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:33:00.735337-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:33:00.735410-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:33:00.735480-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:33:00.735547-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:33:00.735692-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:33:00.735762-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:33:00.735830-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:33:00.735896-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:33:00.735965-0500 HybridPool[1827:594545] rightItem: <null>
2019-02-03 11:33:01.876340-0500 HybridPool[1827:594545] Item added! pool
2019-02-03 11:33:03.352399-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 3
2019-02-03 11:33:03.352967-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:33:03.353179-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:33:03.353377-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:33:03.353569-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:33:03.353755-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:33:03.353897-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:33:03.354230-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:33:03.354612-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:33:03.354739-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:33:03.354848-0500 HybridPool[1827:594545] rightItem: <null>
2019-02-03 11:33:03.477654-0500 HybridPool[1827:594545] cellForRowAtIndexPath getting called - row: 4
2019-02-03 11:33:03.477863-0500 HybridPool[1827:594545] leftItem: Table
2019-02-03 11:33:03.477974-0500 HybridPool[1827:594545] leftItem: Keys
2019-02-03 11:33:03.478078-0500 HybridPool[1827:594545] leftItem: Jhghhvhh
2019-02-03 11:33:03.478178-0500 HybridPool[1827:594545] leftItem: Njhhnn
2019-02-03 11:33:03.478276-0500 HybridPool[1827:594545] leftItem: 9th item
2019-02-03 11:33:03.478374-0500 HybridPool[1827:594545] rightItem: Cord
2019-02-03 11:33:03.478472-0500 HybridPool[1827:594545] rightItem: Hshhdhdbd
2019-02-03 11:33:03.478569-0500 HybridPool[1827:594545] rightItem: Book
2019-02-03 11:33:03.478665-0500 HybridPool[1827:594545] rightItem: Tv
2019-02-03 11:33:03.478763-0500 HybridPool[1827:594545] rightItem: <null>

标签： iosobjective-cuitableviewcordovadelegates

解决方案

表视图中的视图被重用，因此您对视图所做的一切也必须撤消。我的规则是任何涉及可重用视图的代码都不能if没有else. 话虽如此：

if(cell.cellLeftImageView.image == nil) {

是一个错误。视图将在第一次正确设置，但第二次，当视图被重用时，它根本不会设置。

如果：

if(right < [self.items count]) {

也是一个bug。如果没有正确的项目，它不会将图像设置为零，而是会保留之前存在的任何图像。

还有一个数据源，其中奇数和偶数值意味着完全不同的东西真的很难跟踪和理解。你为什么要那样做？您可以拥有具有leftImageURL, rightImageURL, leftText,的对象rightText。编码的一部分是与其他程序员沟通，而不是与编译者沟通。选择一个更容易理解的数据结构可以让代码按照你的预期去做。

接下来，您dataWithContentsOfURL在请求图像时使用 which 会阻塞主线程。我认为这只是文本代码，并不打算以任何严肃的方式使用。

另外，你为什么用valueForKey？的类型是items什么？如果它们是字典，您可以使用 item[@"downloadURL"]，如果它们是一些自定义对象，您应该可以只使用 item.downloadURL。

ios - cordova / ios / 混合应用程序 - UITableView 加载项目不正确且无序

问题描述

解决方案

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