ios - UI 在执行 NSBatchDeleteRequest 时卡住

Question

NSFetchRequest *request = [Report fetchRequest];
request.predicate = [NSPredicate predicateWithFormat: @"reportId IN %@",self.selectedRowsInEditMode];

NSBatchDeleteRequest *deleteDetailsRequest = [[NSBatchDeleteRequest alloc] initWithFetchRequest:request];
deleteDetailsRequest.resultType = NSBatchDeleteResultTypeStatusOnly;
[self.managedObjectContext executeRequest:deleteDetailsRequest error:&errorExecuteRequest];

if (!errorExecuteRequest) {
    NSError *deleteSaveError;
    BOOL saveSuccessful = [self.managedObjectContext save:&deleteSaveError];
    [self.tableView removeLoadingActivityView];

这是我尝试一次删除多个报告托管对象的代码，但是当调用 executeRequest 时，UI 会卡住一段时间然后删除。但是 NSBatchDeleteRequest 在删除方面应该非常快。我尝试了多次修改以使其正常工作但没有成功。我不确定我在这里做错了什么。所以任何人都可以建议让它在没有 UI 故障的情况下工作。

Answer 1

希望对后面的代码有所帮助!!

我最终添加了以下内容以处理批量删除后的上下文。

[self.managedObjectContext refreshAllObjects];

// Initialize Fetch Request
NSFetchRequest *fetchRequest = [Report fetchRequest];

// Add Sort Descriptors
fetchRequest.predicate = [NSPredicate predicateWithFormat: @"reportId IN %@",self.selectedRowsInEditMode];

// Initialize Asynchronous Fetch Request
NSAsynchronousFetchRequest *asynchronousFetchRequest = [[NSAsynchronousFetchRequest alloc] initWithFetchRequest:fetchRequest completionBlock:^(NSAsynchronousFetchResult *result) {
    dispatch_async(dispatch_get_main_queue(), ^{
        // Process Asynchronous Fetch Result
        [weakSelf processAsynchronousFetchResult:result];
    });
}];

// Execute Asynchronous Fetch Request
[self.managedObjectContext performBlock:^{
    // Execute Asynchronous Fetch Request
    NSError *asynchronousFetchRequestError = nil;
    NSAsynchronousFetchResult *asynchronousFetchResult = (NSAsynchronousFetchResult *)[weakSelf.managedObjectContext executeRequest:asynchronousFetchRequest error:&asynchronousFetchRequestError];

    if (asynchronousFetchRequestError) {
        NSLog(@"Unable to execute asynchronous fetch result.");
        NSLog(@"%@, %@", asynchronousFetchRequestError, asynchronousFetchRequestError.localizedDescription);
    }
}];

或者在下面使用你使用全局队列在后台运行东西和主队列来更新 UI

dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
    //Background Thread
    dispatch_async(dispatch_get_main_queue(), ^(void){
        //Run UI Updates
    });
});