问题
I have made Android application a few months ago. The Toast class is very useful for me. I do not need to consider the main Thread and place to show it. Anywhere I can show it and just leave that and it is automatically disappeared.
Toast.makeToast(context, msg, Toast.LENGTH_SHORT).show();
That's it. ^^
What about iPhone? Is there something like the Toast? Just show message and do not need to care about it. It will be automatically disappeared.
回答1:
There is no class "out-of-the-box" in UIKit to do this. But it is quite easy to create a class that will offer this behavior.
You just have to create a class that inherit from UIView. This class will have the responsibility - to create what you want to display, - to add itself in parent view hierarchy - to dismiss itself using a timer.
You will be able to use it like :
[ToastView toastViewInView:myParentView withText:@"what a wonderful text"];
Regards, Quentin
回答2:
I've been writing for Android for a long time and I am missing Toast. I've implemented one. Need code? here you are:
ToastView.h
#import <UIKit/UIKit.h>
@interface ToastView : UIView
@property (strong, nonatomic) NSString *text;
+ (void)showToastInParentView: (UIView *)parentView withText:(NSString *)text withDuaration:(float)duration;
@end
ToastView.m
#import "ToastView.h"
@interface ToastView ()
@property (strong, nonatomic, readonly) UILabel *textLabel;
@end
@implementation ToastView
@synthesize textLabel = _textLabel;
float const ToastHeight = 50.0f;
float const ToastGap = 10.0f;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
-(UILabel *)textLabel
{
if (!_textLabel) {
_textLabel = [[UILabel alloc] initWithFrame:CGRectMake(5.0, 5.0, self.frame.size.width - 10.0, self.frame.size.height - 10.0)];
_textLabel.backgroundColor = [UIColor clearColor];
_textLabel.textAlignment = NSTextAlignmentCenter;
_textLabel.textColor = [UIColor whiteColor];
_textLabel.numberOfLines = 2;
_textLabel.font = [UIFont systemFontOfSize:13.0];
_textLabel.lineBreakMode = NSLineBreakByCharWrapping;
[self addSubview:_textLabel];
}
return _textLabel;
}
- (void)setText:(NSString *)text
{
_text = text;
self.textLabel.text = text;
}
+ (void)showToastInParentView: (UIView *)parentView withText:(NSString *)text withDuaration:(float)duration;
{
//Count toast views are already showing on parent. Made to show several toasts one above another
int toastsAlreadyInParent = 0;
for (UIView *subView in [parentView subviews]) {
if ([subView isKindOfClass:[ToastView class]])
{
toastsAlreadyInParent++;
}
}
CGRect parentFrame = parentView.frame;
float yOrigin = parentFrame.size.height - (70.0 + ToastHeight * toastsAlreadyInParent + ToastGap * toastsAlreadyInParent);
CGRect selfFrame = CGRectMake(parentFrame.origin.x + 20.0, yOrigin, parentFrame.size.width - 40.0, ToastHeight);
ToastView *toast = [[ToastView alloc] initWithFrame:selfFrame];
toast.backgroundColor = [UIColor darkGrayColor];
toast.alpha = 0.0f;
toast.layer.cornerRadius = 4.0;
toast.text = text;
[parentView addSubview:toast];
[UIView animateWithDuration:0.4 animations:^{
toast.alpha = 0.9f;
toast.textLabel.alpha = 0.9f;
}completion:^(BOOL finished) {
if(finished){
}
}];
[toast performSelector:@selector(hideSelf) withObject:nil afterDelay:duration];
}
- (void)hideSelf
{
[UIView animateWithDuration:0.4 animations:^{
self.alpha = 0.0;
self.textLabel.alpha = 0.0;
}completion:^(BOOL finished) {
if(finished){
[self removeFromSuperview];
}
}];
}
@end
Call from ViewController
[ToastView showToastInParentView:self.view withText:@"What a toast!" withDuaration:5.0];
回答3:
Have not tried but you might want to check:
https://github.com/ecstasy2/toast-notifications-ios
https://github.com/scalessec/Toast
回答4:
Edit: Updated for Swift 3
Here is a Swift 3 version based on wojciech_maciejewski's answer. This looks more like Android Toast and doesn't stack toasts on each other. It draws toast into the center of the screen. It can handle long multiline texts.
import UIKit
class ToastView: UIView {
private static let hLabelGap: CGFloat = 40.0
private static let vLabelGap: CGFloat = 20.0
private static let hToastGap: CGFloat = 20.0
private static let vToastGap: CGFloat = 10.0
private var textLabel: UILabel!
static func showInParent(_ parentView: UIView, _ text: String, duration: Double = 3.0) {
let labelFrame = CGRect(x: parentView.frame.origin.x + hLabelGap,
y: parentView.frame.origin.y + vLabelGap,
width: parentView.frame.width - 2 * hLabelGap,
height: parentView.frame.height - 2 * vLabelGap)
let label = UILabel()
label.font = UIFont.systemFont(ofSize: 15.0)
label.text = text
label.backgroundColor = UIColor.clear
label.textAlignment = NSTextAlignment.center
label.textColor = UIColor.white
label.numberOfLines = 0
label.frame = labelFrame
label.sizeToFit()
let toast = ToastView()
toast.textLabel = label
toast.addSubview(label)
toast.frame = CGRect(x: label.frame.origin.x - hToastGap,
y: label.frame.origin.y - vToastGap,
width: label.frame.width + 2 * hToastGap,
height: label.frame.height + 2 * vToastGap)
toast.backgroundColor = UIColor.darkGray
toast.alpha = 0.0
toast.layer.cornerRadius = 20.0
toast.center = parentView.center
label.center = CGPoint(x: toast.frame.size.width / 2, y: toast.frame.size.height / 2)
parentView.addSubview(toast)
UIView.animate(withDuration: 0.4, animations: {
toast.alpha = 0.9
label.alpha = 0.9
})
toast.perform(#selector(hideSelf), with: nil, afterDelay: duration)
}
@objc private func hideSelf() {
UIView.animate(withDuration: 0.4, animations: {
self.alpha = 0.0
self.textLabel.alpha = 0.0
}, completion: { t in self.removeFromSuperview() })
}
}
Usage from another controller:
ToastView.showInParent(navigationController!.view, "Hello world")
回答5:
I'm posting swift version of Scarmysun answer:) many thanks
import Foundation
import UIKit
class ToastView: UIView {
static let toastHeight:CGFloat = 50.0
static let toastGap:CGFloat = 10;
lazy var textLabel: UILabel = UILabel(frame: CGRectMake(5.0, 5.0, self.frame.size.width - 10.0, self.frame.size.height - 10.0))
static func showInParent(parentView: UIView!, withText text: String, forDuration duration: double_t) {
//Count toast views are already showing on parent. Made to show several toasts one above another
var toastsAlreadyInParent = 0;
for view in parentView.subviews {
if (view.isKindOfClass(ToastView)) {
toastsAlreadyInParent++
}
}
var parentFrame = parentView.frame;
var yOrigin = parentFrame.size.height - getDouble(toastsAlreadyInParent)
var selfFrame = CGRectMake(parentFrame.origin.x + 20.0, yOrigin, parentFrame.size.width - 40.0, toastHeight);
var toast = ToastView(frame: selfFrame)
toast.textLabel.backgroundColor = UIColor.clearColor()
toast.textLabel.textAlignment = NSTextAlignment.Center
toast.textLabel.textColor = UIColor.whiteColor()
toast.textLabel.numberOfLines = 2
toast.textLabel.font = UIFont.systemFontOfSize(13.0)
toast.addSubview(toast.textLabel)
toast.backgroundColor = UIColor.darkGrayColor()
toast.alpha = 0.0;
toast.layer.cornerRadius = 4.0;
toast.textLabel.text = text;
parentView.addSubview(toast)
UIView.animateWithDuration(0.4, animations: {
toast.alpha = 0.9
toast.textLabel.alpha = 0.9
})
toast.performSelector(Selector("hideSelf"), withObject: nil, afterDelay: duration)
}
static private func getDouble(toastsAlreadyInParent : Int) -> CGFloat {
return (70.0 + toastHeight * CGFloat(toastsAlreadyInParent) + toastGap * CGFloat(toastsAlreadyInParent));
}
func hideSelf() {
UIView.animateWithDuration(0.4, animations: {
self.alpha = 0.0
self.textLabel.alpha = 0.0
}, completion: { t in self.removeFromSuperview() })
}
}
回答6:
You can do this in many ways one of the way is using UIAlertViewController() in swift3
let alertManager=UIAlertController(title: nil, message: "Welcome!", preferredStyle: .alert)
self.present(alertManager, animated: true, completion: nil)
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now()+1,
execute: {
alertManager.dismiss(animated: false, completion: nil)
})
来源：https://stackoverflow.com/questions/3522866/what-is-the-android-widget-toast-equivalent-for-ios-applications