在iOS8自定义键盘扩展中获取完整字符串

Question

我正在为iOS 8创建自定义键盘扩展.

我想获取用户在文本输入字段中编写的整个字符串.

不幸的是,我偶然发现了两个主要问题:

1)我在这个回调中得到null:

- (void)textDidChange:(id<UITextInput>)textInput

2)当我调用这些方法时,我只得到部分字符串:

- [self.textDocumentProxy documentContextAfterInput];
- [self.textDocumentProxy documentContextBeforeInput];

我想在用户正在编辑的文本输入中获取整个字符串,您建议我做什么？

谢谢!

Answer 1

我发现了如何.

- (void)doSomething{
    dispatch_async(inputQueue, ^{
        [self getAllString];
    });
    return;
}

首先使用dispatch_async和您自己的队列包装您的方法.

#define DELAY_LENGTH 0.01

-(void)getAllString{
    id<UITextDocumentProxy> proxy = self.textDocumentProxy;
    NSString* before = [proxy documentContextBeforeInput];
    NSString* after = [proxy documentContextAfterInput];

    NSMutableArray* afterArray = [NSMutableArray arrayWithCapacity:10];

    while (after) {
        unsigned long afterLength = [after length];
        if(afterLength <= 0){
            break;
        }
        [afterArray addObject:after];
        [NSThread sleepForTimeInterval:DELAY_LENGTH];
        [proxy adjustTextPositionByCharacterOffset:afterLength];
        [NSThread sleepForTimeInterval:DELAY_LENGTH];
        after = [proxy documentContextAfterInput];
    }

    NSMutableArray* beforeArray = [NSMutableArray arrayWithCapacity:10];

    [NSThread sleepForTimeInterval:DELAY_LENGTH];
    before = [proxy documentContextBeforeInput];

    while (before) {
        unsigned long beforeLength = [before length];
        if (beforeLength <= 0) {
            break;
        }
        [beforeArray addObject:before];
        [NSThread sleepForTimeInterval:DELAY_LENGTH];
        [proxy adjustTextPositionByCharacterOffset:-beforeLength];
        [NSThread sleepForTimeInterval:DELAY_LENGTH];
        before = [proxy documentContextBeforeInput];
    }

    NSLog(@"afterArray: %@",[self getArrayString:afterArray reverse:false]);

    NSString* beforeString = [self getArrayString:beforeArray reverse:true];

    NSLog(@"beforArray: %@",beforeString);

    [NSThread sleepForTimeInterval:DELAY_LENGTH];
    [proxy adjustTextPositionByCharacterOffset:beforeString.length];
}

有两个工具:

@implementation NSArray (Reverse)

- (NSArray *)reversedArray {
    NSMutableArray *array = [NSMutableArray arrayWithCapacity:[self count]];
    NSEnumerator *enumerator = [self reverseObjectEnumerator];
    for (id element in enumerator) {
        [array addObject:element];
    }
    return array;
}

@end

和

-(NSString*)getArrayString : (NSArray*)array
                   reverse : (BOOL)isReverse{
    NSArray* tar = isReverse ? [array reversedArray] : array;
    NSMutableString* result = [NSMutableString stringWithCapacity:10];
    for (NSString* string in tar) {
        [result appendString:string];
    }
    return result;
}

对于每种代理方法,你都要小睡一些.

结果:

文本框

012, 345! 6789
0123. 4567! 89012 '34567890.' 123456789

安慰

2015-03-18 21:04:15.034 moveCursor[39413:2692914] afterArray: 
2015-03-18 21:04:15.035 moveCursor[39413:2692914] beforArray: 012, 345! 6789
0123. 4567! 89012 '34567890.' 123456789

Answer 2

我在 documentContextAfterInput 和 documentContextBeforeInput 字符串中遇到了同样的问题。我认为 IOS8 只返回插入点两侧的少数字符。我认为这是故意的。