1、全局異步執(zhí)行耗時任務

dispatch_async(dispatch_get_global_queue(0, 0), ^{

});

2.主線程異步刷新UI

dispatch_async(dispatch_get_main_queue(), ^{

});

3.改變PlaceHolder的顏色

[username_text setValue:[UIColor colorWithRed:1 green:1

blue:1 alpha:0.5]

forKeyPath:@"_placeholderLabel.textColor"];

4.解決鍵盤彈起擋住文本框的問題

//鍵盤彈起時重置View大小

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent

*)event{

[username_text resignFirstResponder];

[password_text resignFirstResponder];

NSTimeInterval animationDuration = 0.30f;

[UIView beginAnimations:@"ResizeForKeyboard"context:nil];

[UIView setAnimationDuration:animationDuration];

CGRect rect = CGRectMake(0.0f, 0.0f,self.view.frame.size.width,self.view.frame.size.height);

self.view.frame = rect;

[UIView commitAnimations];

}

?

?

//退出編輯（鍵盤落下）重置View大小

- (BOOL)textFieldShouldReturn:(UITextField *)textField

{

NSTimeInterval animationDuration = 0.30f;

[UIView beginAnimations:@"ResizeForKeyboard"context:nil];

[UIView setAnimationDuration:animationDuration];

CGRect rect = CGRectMake(0.0f, 0.0f,self.view.frame.size.width,self.view.frame.size.height);

self.view.frame = rect;

[UIView commitAnimations];

[textField resignFirstResponder];

return YES;

}

?

5.開始編輯（鍵盤彈起）通過控件Y坐標計算View顯示范圍

- (void)textFieldDidBeginEditing:(UITextField *)textField

{

CGRect frame = password_text.frame;

int offset = frame.origin.y + 32 -

(self.view.frame.size.height - 216.0);

NSTimeInterval animationDuration = 0.30f;

[UIView beginAnimations:@"ResizeForKeyBoard"

context:nil];

[UIView setAnimationDuration:animationDuration];

floatwidth =self.view.frame.size.width;

floatheight =self.view.frame.size.height;

if(offset > 0)

{

CGRect rect = CGRectMake(0.0f, -

offset,width,height);

self.view.frame = rect;

}

[UIView commitAnimations];

}

轉載于:https://www.cnblogs.com/CJH5209/p/6072129.html

總結

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