我对Objective C很新，而且我在将plist中的值读入一组NSArray时遇到了麻烦。我尝试引用this question但没有运气。
我有3个数组，我试图加载到我的选择器中。我想加载的3个数组是数组转换，typesFrom和typesTo。 typesFrom和typesTo包含相同的值，但根据转换类型而改变。
目前，选择器将加载3列但没有行。我觉得这可能是一个简单的解决方案，但我已经尝试了几个小时但似乎无法找到它。 / p>
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
// Grab information from the plist
NSBundle *bundle = [NSBundle mainBundle];
NSString *plistPath = [bundle
pathForResource:@"conversions"
ofType:@"plist"
];
NSDictionary *dictionary = [[NSDictionary alloc]
initWithContentsOfFile:plistPath
];
// Store conversions
for(NSDictionary *dict in [dictionary valueForKey:@"Conversions"]) {
[self.conversions arrayByAddingObject:[dict valueForKey:@"name"]];
[self.categories arrayByAddingObject:[dict valueForKey:@"conversions"]];
}
[dictionary release];
[self loadIntoPicker:0];
}
- (void)loadIntoPicker:(NSInteger)index {
// Set the current category
NSArray *category = [self.categories objectAtIndex:index];
for (NSDictionary *conversion in category) {
[self.typesFrom arrayByAddingObject:[conversion valueForKey:@"type"]];
[self.typesTo arrayByAddingObject:[conversion valueForKey:@"type"]];
[self.descriptions arrayByAddingObject:[conversion valueForKey:@"description"]];
[self.multipliers arrayByAddingObject:[conversion valueForKey:@"multiplier"]];
}
[picker selectRow:0 inComponent:1 animated:YES];
[picker selectRow:0 inComponent:2 animated:YES];
[picker reloadComponent:1];
[picker reloadComponent:2];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 3;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
if ( component == kCategoryComponent )
return [self.conversions count];
else
return [self.typesFrom count];
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
if ( component == kCategoryComponent )
return [self.conversions objectAtIndex:row];
else if ( component == kConvertFromComponent )
return [self.typesFrom objectAtIndex:row];
else
return [self.typesTo objectAtIndex:row];
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
if ( component == kCategoryComponent ) {
if ( row >= 0 )
[self loadIntoPicker:row];
}
}
我正在使用的plist：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Conversions</key>
<array>
<dict>
<key>name</key>
<string>Speed</string>
<key>conversions</key>
<array>
<dict>
<key>type</key>
<string>mph</string>
<key>description</key>
<string>mile/hour</string>
<key>multiplier</key>
<integer>1</integer>
</dict>
<dict>
<key>type</key>
<string>ft/s</string>
<key>description</key>
<string>foot/second</string>
<key>multiplier</key>
<real>1.466667</real>
</dict>
<dict>
<key>type</key>
<string>km/h</string>
<key>description</key>
<string>kilometer/hour</string>
<key>multiplier</key>
<real>1.609344</real>
</dict>
<dict>
<key>type</key>
<string>m/s</string>
<key>description</key>
<string>meter/second</string>
<key>multiplier</key>
<real>0.44704</real>
</dict>
</array>
</dict>
<dict>
<key>name</key>
<string>Distance</string>
<key>conversions</key>
<array>
<dict>
<key>type</key>
<string>ft</string>
<key>description</key>
<string>feet</string>
<key>multiplier</key>
<integer>1</integer>
</dict>
<dict>
<key>type</key>
<string>yd</string>
<key>description</key>
<string>yard</string>
<key>multiplier</key>
<real>0.3333333</real>
</dict>
<dict>
<key>type</key>
<string>mi</string>
<key>description</key>
<string>mile</string>
<key>multiplier</key>
<real>0.0001894</real>
</dict>
<dict>
<key>type</key>
<string>in</string>
<key>description</key>
<string>inch</string>
<key>multiplier</key>
<integer>12</integer>
</dict>
<dict>
<key>type</key>
<string>m</string>
<key>description</key>
<string>meter</string>
<key>multiplier</key>
<real>0.3048</real>
</dict>
<dict>
<key>type</key>
<string>km</string>
<key>description</key>
<string>kilometer</string>
<key>multiplier</key>
<real>0.0003048</real>
</dict>
<dict>
<key>type</key>
<string>cm</string>
<key>description</key>
<string>centimeter</string>
<key>multiplier</key>
<real>30.48</real>
</dict>
</array>
</dict>
<dict>
<key>name</key>
<string>Volume</string>
<key>conversions</key>
<array>
<dict>
<key>type</key>
<string>ft^3</string>
<key>description</key>
<string>cubic feet</string>
<key>multiplier</key>
<integer>1</integer>
</dict>
<dict>
<key>type</key>
<string>liter</string>
<key>description</key>
<string>liter</string>
<key>multiplier</key>
<real>28.31685</real>
</dict>
<dict>
<key>type</key>
<string>acre ft</string>
<key>description</key>
<string>acre foot</string>
<key>multiplier</key>
<real>2.3e-05</real>
</dict>
<dict>
<key>type</key>
<string>barrel</string>
<key>description</key>
<string>barrel [US, liquid]</string>
<key>multiplier</key>
<real>0.2374768</real>
</dict>
<dict>
<key>type</key>
<string>gallon</string>
<key>description</key>
<string>gallon [US, liquid]</string>
<key>multiplier</key>
<real>29.92208</real>
</dict>
<dict>
<key>type</key>
<string>quart</string>
<key>description</key>
<string>quart [US, liquid]</string>
<key>multiplier</key>
<real>29.92208</real>
</dict>
</array>
</dict>
</array>
</dict>
</plist>
答案 0 :(得分：1)
看起来你的数组没有被初始化或正确填充。
arrayByAddingObject:返回包含添加对象的新数组，但您没有使用这些语句的返回值。
如果您的数组是NSMutableArray属性，请尝试以下代码：
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
// Grab information from the plist
NSBundle *bundle = [NSBundle mainBundle];
NSString *plistPath = [bundle
pathForResource:@"conversions"
ofType:@"plist"
];
NSDictionary *dictionary = [[NSDictionary alloc]
initWithContentsOfFile:plistPath
];
self.conversions = [NSMutableArray arrayWithCapacity:0];
self.categories = [NSMutableArray arrayWithCapacity:0];
// Store conversions
for(NSDictionary *dict in [dictionary valueForKey:@"Conversions"]) {
[self.conversions addObject:[dict valueForKey:@"name"]];
[self.categories addObject:[dict valueForKey:@"conversions"]];
}
[dictionary release];
[self loadIntoPicker:0];
}
如果它们是NSArray类型，您可以像这样修改代码：
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
// Grab information from the plist
NSBundle *bundle = [NSBundle mainBundle];
NSString *plistPath = [bundle
pathForResource:@"conversions"
ofType:@"plist"
];
NSDictionary *dictionary = [[NSDictionary alloc]
initWithContentsOfFile:plistPath
];
NSMutableArray *tempConversions = [NSMutableArray arrayWithCapacity:0];
NSMutableArray *tempCategories = [NSMutableArray arrayWithCapacity:0];
// Store conversions
for(NSDictionary *dict in [dictionary valueForKey:@"Conversions"]) {
[tempConversions addObject:[dict valueForKey:@"name"]];
[tempCategories addObject:[dict valueForKey:@"conversions"]];
}
[dictionary release];
self.conversions = tempConversions;
self.categories = tempCategories;
[self loadIntoPicker:0];
}