UIPickerView的使用

UIPickerView功能与UIDatePicker类似

初始化实例时，通常只需要设置原点坐标，不需要设置宽高（默认宽高为：frame = (0 0; 320 216)）

区别在于:

1、UIPickerView需要自定义实现数据类型（包括：数据源，列数等）

[objc] view
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@interface ViewController () <UIPickerViewDelegate, UIPickerViewDataSource>

@property (nonatomic, strong) NSDictionary *sourceDict;

@property (nonatomic, strong) NSString *rowTitleFirst;

@property (nonatomic, strong) NSString *rowTitleSecond;

@property (nonatomic, strong) NSString *rowTitleThird;

@property (nonatomic, strong) UITextField *textfield;

@end

[objc] view
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UIPickerView *pickerView = [[UIPickerView alloc] init];

// [self.view addSubview:pickerView];

pickerView.backgroundColor = [UIColor orangeColor];

NSLog(@"pickerView %@", pickerView);

[objc] view
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/*

设置代理

1 包括代理对象，及数据源代理对象

2 实现代理方法的对象

3 添加协议

4 实现代理方法

注意事项

1、两种代理必须同时实现

2、标题显示设置三选一，只设置其中一个方法即可

2-1、- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component

2-2、- (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component

2-3、- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view

*/

pickerView.delegate = self;

pickerView.dataSource = self;

[objc] view
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// 设置数据源

NSArray *meizhouArray = @[@"梅县", @"五华县", @"丰顺县", @"大埔县", @"蕉岭县", @"兴宁市", @"梅江区"];

NSArray *guangzhouArray = @[@"天河区", @"白云区", @"荔湾区", @"番禺区", @"海珠区", @"花都区", @"从化区", @"增城区"];

NSArray *shenzhenArray = @[@"龙华新区", @"大鹏新区", @"福田区", @"罗湖区", @"宝安区", @"龙岗区", @"南山区"];

NSDictionary *guangdongCityDict = [NSDictionary dictionaryWithObjectsAndKeys:shenzhenArray, @"深圳市", guangzhouArray, @"广州市", meizhouArray, @"梅州市", nil nil];

NSDictionary *guangxiCityDict = [NSDictionary dictionaryWithObjectsAndKeys:@[], @"柳州市", @[], @"桂林市", nil nil];

self.sourceDict = [NSDictionary dictionaryWithObjectsAndKeys:guangdongCityDict, @"广东省", guangxiCityDict, @"广西省", nil nil];

[objc] view
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// 设置默认值

self.rowTitleFirst = @"广东省";

self.rowTitleSecond = @"深圳市";

[pickerView selectRow:0 inComponent:0 animated:NO];

[pickerView selectRow:0 inComponent:1 animated:NO];

[pickerView selectRow:3 inComponent:2 animated:NO];

[objc] view
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// 刷新数据

[pickerView reloadAllComponents];

[objc] view
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// 通过textfield来使用

self.textfield = [[UITextField alloc] initWithFrame:CGRectMake(10.0, 50.0, (CGRectGetWidth(self.view.bounds) - 10.0 * 2), 40.0)];

[self.view addSubview:self.textfield];

self.textfield.backgroundColor = [UIColor yellowColor];

self.textfield.textColor = [UIColor redColor];

self.textfield.placeholder = @"请选择地址（省市区）";

// 添加键盘上方的子视图

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

button.frame = CGRectMake(0.0, 0.0, CGRectGetWidth(self.view.bounds), 40.0);

button.backgroundColor = [UIColor greenColor];

[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];

[button setTitleColor:[UIColor redColor] forState:UIControlStateHighlighted];

[button setTitle:@"隐藏键盘" forState:UIControlStateNormal];

[button addTarget:self action:@selector(hiddenKeyboard:) forControlEvents:UIControlEventTouchUpInside];

self.textfield.inputAccessoryView = button;

//输入源改成地址选择视图

self.textfield.inputView = pickerView;

[objc] view
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// UIPickerViewDelegate

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component

{

// 设置列的宽度

return 100.0;

}

- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component

{

// 设置列中的每行的高度

return 40.0;

}

- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component

{

// 设置列中的每行的显示标题NSString

// 设置每列每行的标题

NSArray *keyArray = self.sourceDict.allKeys;

if (0 == component)

{

NSString *title = keyArray[row];

return title;

}

else if (1 ==component)

{

NSDictionary *cityDict = self.sourceDict[self.rowTitleFirst];

NSArray *cityArray = cityDict.allKeys;

NSString *title = cityArray[row];

return title;

}

else if (2 == component)

{

NSDictionary *areaDict = self.sourceDict[self.rowTitleFirst];

NSArray *areaArray = areaDict[self.rowTitleSecond];

NSString *title = areaArray[row];

return title;

}

return nil;

}

//- (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component

//{

// // 设置列中的每行的显示标题NSAttributedString

// return nil;

//}

//- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view

//{

// // 设置列中的每行的自定义视图

// return nil;

//}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

{

// 获取列中选中的某一行

NSLog(@"component = %ld, row = %ld", component, row);

NSArray *keyArray = self.sourceDict.allKeys;

if (0 == component)

{

NSString *keyFirst = keyArray[row];

// 设置第一列的值，即key1

self.rowTitleFirst = keyFirst;

// 当第一列改变时，第二列的值应该跟着改变，即key2，设置为默认第二列的第一个值

NSDictionary *cityDict = self.sourceDict[self.rowTitleFirst];

NSArray *cityArray = cityDict.allKeys;

if (cityArray && 0 < cityArray.count)

{

NSString *keySecond = cityArray[0];

self.rowTitleSecond = keySecond;

}

// 设置第三个标题，当第二列改变时，第三wfhr值路着改变

NSArray *areaArray = cityDict[self.rowTitleSecond];

if (areaArray && 0 < areaArray.count)

{

NSString *keyThird = areaArray[0];

self.rowTitleThird = keyThird;

}

else

{

// 没有第三列时，将第三列的默认标题设置为空

self.rowTitleThird = nil;

}

// 重新刷新第2列的数据，且设置显示为第一行

[pickerView reloadComponent:1];

[pickerView selectRow:0 inComponent:1 animated:YES];

// 重新刷新第3列的数据，且设置显示为第一行

[pickerView reloadComponent:2];

[pickerView selectRow:0 inComponent:2 animated:YES];

}

else if (1 ==component)

{

// 设置第二个标题

NSDictionary *cityDict = self.sourceDict[self.rowTitleFirst];

NSArray *cityArray = cityDict.allKeys;

NSString *keySecond = cityArray[row];

self.rowTitleSecond = keySecond;

// 设置第三个标题，默认第一行

NSArray *areaArray = cityDict[self.rowTitleSecond];

if (areaArray && 0 < areaArray.count)

{

NSString *keyThird = areaArray[0];

self.rowTitleThird = keyThird;

}

// 重新刷新第3列的数据，且设置显示为第一行

[pickerView reloadComponent:2];

[pickerView selectRow:0 inComponent:2 animated:YES];

}

else if (2 == component)

{

// 设置第三个标题

NSDictionary *cityDict = self.sourceDict[self.rowTitleFirst];

NSArray *areaArray = cityDict[self.rowTitleSecond];

if (areaArray && 0 < areaArray.count)

{

NSString *keyThird = areaArray[row];

self.rowTitleThird = keyThird;

}

}

NSString *text = [NSString stringWithFormat:@"%@%@%@", self.rowTitleFirst, self.rowTitleSecond, self.rowTitleThird];

NSLog(@"选择结果：%@", text);

self.textfield.text = text;

}

[objc] view
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// UIPickerViewDataSource

// returns the number of 'columns' to display.

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

{

// 设置列数

// 设置三列：省、市、区

return 3;

}

// returns the # of rows in each component..

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component

{

// 设置每列的行数

// 设置每列的实际行数

NSArray *keyArray = self.sourceDict.allKeys;

if (0 == component)

{

return keyArray.count;

}

else if (1 ==component)

{

NSDictionary *cityDict = self.sourceDict[self.rowTitleFirst];

NSArray *cityArray = cityDict.allKeys;

return cityArray.count;

}

else if (2 == component)

{

NSDictionary *areaDict = self.sourceDict[self.rowTitleFirst];

NSArray *areaArray = areaDict[self.rowTitleSecond];

return areaArray.count;

}

return 0;

}

[objc] view
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// 隐藏键盘

- (void)hiddenKeyboard:(UIButton *)button

{

[self.view endEditing:YES];

}