创建类似于iPhone消息传递应用程序的UITextField / UITextView

Question

你怎么能创建一个UITextField非常类似苹果在他们的消息应用程序，Instagram使用，edmodo使用，Whatsapp使用和许多其他消息共享应用程序中使用的？此文本字段应设置动画，动画显示，可以展开，只能达到一定高度，并具有其他属性。

Answer 1

我研究了一段时间，但找不到答案所以我只是创造了自己的方式去做。你必须做几件事。首先，这确实使用了UITextView而不是UITextField。其次，这段代码专为iPhone 5编写，因此您可能需要使用坐标。它不使用大小调整类或约束。 1您需要实施第一个。您的.h文件应如下所示：

int returnPressed = 0;
int newLine;

@interface ViewController : UIViewController <UITextViewDelegate>
{
IBOutlet UIView *dock;
IBOutlet UIButton *sendButton;
IBOutlet UITextView *textView1;

CGRect previousRect;

}

@end

在.m文件中，需要满足许多需求才能使其看起来像iPhone消息应用程序的外观。您会注意到我们如何在这里创建自己的自定义占位符，因为textview并不真正拥有它们。这是.m文件：

- (void)viewDidLoad {
[super viewDidLoad];

previousRect = CGRectZero;

textView1.delegate = self;

self->textView1.layer.borderWidth = 1.0f;
self->textView1.layer.borderColor = [[UIColor lightGrayColor] CGColor];
self->textView1.layer.cornerRadius = 6;
self->textView1.textColor = [UIColor lightGrayColor];
self->textView1.text = @"Place Holder";






    }


- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
if ([text isEqualToString:@"\n"]) {

    returnPressed +=1;

    if(returnPressed < 17){

    textView1.frame = CGRectMake(8, 8, textView1.frame.size.width, textView1.frame.size.height + 17);

    newLine = 17*returnPressed;

    [UIView animateWithDuration:0.1 animations:^
     {
         dock.transform = CGAffineTransformMakeTranslation(0, -250 - newLine);
     }
     ];

    }
}

return YES;
}


- (void)textViewDidChange:(UITextView *)textView{

UITextPosition* pos = textView1.endOfDocument;

CGRect currentRect = [textView1 caretRectForPosition:pos];

if (currentRect.origin.y > previousRect.origin.y || [textView1.text isEqualToString:@"\n"]){

    returnPressed +=1;

    if(returnPressed < 17 && returnPressed > 1){

        textView1.frame = CGRectMake(8, 8, textView1.frame.size.width, textView1.frame.size.height + 17);

        newLine = 17*returnPressed;

        [UIView animateWithDuration:0.1 animations:^
         {
             dock.transform = CGAffineTransformMakeTranslation(0, -250 - newLine);
         }
         ];

    }
}
previousRect = currentRect;


}



- (BOOL)textViewShouldBeginEditing:(UITextView *)textField {


if([textView1.text isEqualToString:@""] || [textView1.text isEqualToString:@"Place Holder"]){
textView1.text = @"";
}

textView1.textColor = [UIColor blackColor];

[UIView animateWithDuration:0.209 animations:^
 {
     dock.transform = CGAffineTransformMakeTranslation(0, -250 - newLine);
 }
                 completion:^(BOOL finished){}];

return YES;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch * touch = [touches anyObject];
if(touch.phase == UITouchPhaseBegan) {
    [textView1 resignFirstResponder];
    [self.view endEditing:YES];

    int height = returnPressed*20;

    [UIView animateWithDuration:0.209 animations:^
     {
         dock.transform = CGAffineTransformMakeTranslation(0, -height);
     }];

    if([textView1.text isEqualToString:@""]){
        self->textView1.textColor = [UIColor lightGrayColor];
        self->textView1.text = @"Place Holder";
    }
}
}

这就是一切。我希望这可以帮助那些尝试这样做的人，我希望你能将它整合到你的app中。

Answer 2

有一个可以用于增长文本视图的窗格： https://cocoapods.org/pods/HPGrowingTextView

通过这种方式，您可以管理动画和文本视图的最大高度。