Objective c 根据coredata中匹配的字符串选择UIPickerview

我有一个表单，一旦用户提交，它应该重新加载视图（但会改变一些事情）

在此表单上有一个UIPickerview（_tripPicker），它有两个位置：起始位置和结束位置（pickerview的两个组件）

我将它保存到适当的数据库和所有这些——但是当它重新加载（当用户单击保存时），我希望pickerview“重置”，第一个位置（begSchool）与用户刚刚保存到coredata的第二个位置（endSchool）相匹配

例如：假设用户从点B转到点C（pickerview中的组件分别为0和1）；当他们单击“保存”时，我希望组件0显示“PointC”，而第二个组件只显示要转到的点列表（将其重置为最初的加载方式）

我尝试过做一些匹配字符串的工作，但遇到了一些问题

以下是我这样做的逻辑：

//Save the data & reload View
[[NSManagedObjectContext MR_defaultContext] MR_saveToPersistentStoreWithCompletion:^(BOOL success, NSError *error) {

//Reset the pickerview  **********THIS LOGIC NEEDS WORK**********
//Check to see if there is previous UserMiles entered - if so, set beg_school to appropriate name
// Get the local context
NSArray *tripsSorted = [UserMiles MR_findAllSortedBy:@"driven_date" ascending:NO];
if (!tripsSorted || !tripsSorted.count){
    //if no previous trips have been entered - set the school list to default
    begSchoolLabel.text = [_schoolArray1 objectAtIndex:[_tripPicker selectedRowInComponent:0]];

} else {
    UserMiles *lastTrip = [tripsSorted objectAtIndex:0];
    NSString *preValue = lastTrip.end_school;
    begSchoolLabel.text = preValue;
    NSUInteger *currentIndex = [_schoolArray1 indexOfObject:preValue]; //Error/warning that incompatible integer to point conversion
    [_tripPicker selectRow:currentIndex inComponent:0 animated:YES];  //Error/warning here that incompatible point to integer conversion
    NSLog(@"LastTrip.endSchool = %@", lastTrip.end_school);
}

//Set end school labels for the second component in the picker
endSchoolLabel.text = [_schoolArray2 objectAtIndex:[_tripPicker selectedRowInComponent:1]];

NSLog (@"saveInBackground: finished!");

}];
[self.view setNeedsDisplay];

lastTrip.end_school从pickerview的组件1中获取学校的适当名称，我只需要找出如何将其与加载pickerview的数组中的适当值匹配，并使其在pickerview中被选中。文本当前显示适当的名称，但pickerview未显示任何更改

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请告诉我是否需要澄清，或者您需要查看哪些其他代码-提前感谢。

我可以通过将字符串与数组中的对象进行匹配，首先在数组中找到indexValue来解决此问题

我的结局是：

//Save the data & reload View
[[NSManagedObjectContext MR_defaultContext] MR_saveToPersistentStoreWithCompletion:^(BOOL success, NSError *error) {

//Reset the pickerview  **********THIS LOGIC NEEDS WORK**********
//Check to see if there is previous UserMiles entered - if so, set beg_school to appropriate name
// Get the local context
NSArray *tripsSorted = [UserMiles MR_findAllSortedBy:@"driven_date" ascending:NO];
if (!tripsSorted || !tripsSorted.count){
    //if no previous trips have been entered - set the school list to default
    begSchoolLabel.text = [_schoolArray1 objectAtIndex:[_tripPicker selectedRowInComponent:0]];

} else {
    UserMiles *lastTrip = [tripsSorted lastObject];
    NSString *preValue = lastTrip.end_school;
    begSchoolLabel.text = preValue;
    int indexValue = [_schoolArray1 indexOfObject:preValue]; //Compares the preValue string to the strings in the array and finds the indexValue of the right match
    [_tripPicker selectRow:indexValue inComponent:0 animated:YES]; //Sets the picker to the appropriate value
    NSLog(@"LastTrip.endSchool = %@", lastTrip.end_school);
}

//Set end school labels for the second component in the picker
endSchoolLabel.text = [_schoolArray2 objectAtIndex:[_tripPicker selectedRowInComponent:1]];

NSLog (@"saveInBackground: finished!");

}];
[self.view setNeedsDisplay];