公司产品有个功能是cell右边放了一个switch控件,在操作状态的时候通过网络请求来改变最后的状态。
实现代码如下:
- (UITableViewCell *)lh_tableView:(LHBaseTableView *)baseView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
...
@weakify(self)
cell.cellOperationHandler = ^(LHBaseTableViewCell *eventCell, UIView *sender, NSObject *info, void (^completion)(NSError *)) {
NSIndexPath *cellIndexPath = [baseView indexPathForCell:eventCell];
LHLinkage *linkage = weak_self.viewModel.linkageGroupList[indexPath.row];
[linkage changeLinakgeStatusCompletion:^(BOOL isSuccess, NSError *error) {
if (error) {
[LHTipsUtils showError:error];
}
if (completion) {
completion(error);
}
}];
};
...
}
- (void)onSwitchValueChange:(UISwitch *)sender{
if(self.cellOperationHandler){
sender.enabled = false;
__weak typeof(self) weakself = self;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
BOOL oldValue = !sender.isOn;
weakself.cellOperationHandler(weakself, sender, [NSNumber numberWithBool:sender.isOn], ^(NSError *error) {
sender.enabled = true;
if (error) {
[sender setOn:oldValue animated:true];
}
});
});
}
}
然后测试妹纸反馈说有时候状态不对,查了下代码开始发现没有什么不对的啊,我们知道tableView:(LHBaseTableView *)baseView cellForRowAtIndexPath:(NSIndexPath *)indexPath
因为重用关系,indexPath是不可靠的,但是这里是用的indexPathForCell:
方法,为啥也会出问题?
然后写了测试代码:
在cell上Switch执行的时候,快速的滑动tableView
然后控制台打印结果:
Printing description of test:
<NSIndexPath: 0xc000000000000016> {length = 2, path = 0 - 0}
Printing description of indexPath:
<NSIndexPath: 0xc000000001200016> {length = 2, path = 0 - 9}
发现这时候确实是发生变化了。
那这里最好的办法就是把当前cell操作的indexPath给存起来,然后操作完毕后给到外面,就是把数据源和UI操作分开。
改动后的代码:
- (void)onSwitchValueChange:(UISwitch *)sender{
if(self.cellOperationHandler){
sender.enabled = false;
__weak typeof(self) weakself = self;
NSIndexPath *indexPath;
if ([self.superview isKindOfClass:[UITableView class]]) {
indexPath = [((UITableView *)self.superview) indexPathForCell:self];
}
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
BOOL oldValue = !sender.isOn;
weakself.cellOperationHandler(weakself, indexPath, sender, [NSNumber numberWithBool:sender.isOn], ^(NSError *error) {
sender.enabled = true;
if (error) {
[sender setOn:oldValue animated:true];
}
});
});
}
}