我发现使用服务上传图像很有用，但是我无法恢复在DateDemo2之后设置的import Foundation
import XCTest
class DateDecodeTests: XCTestCase {
class DateDemo :Decodable {
var dates : [Date]
var eventsDateTimes : [Date]?
var eventsDateTimes2 : [Date]?
}
class DateDemo2 : DateDemo {
var eventsDateTimes3 : [Date]?
}
func testDateDecoding() throws {
let json = """
{
"dates": ["2018-10-17T23:00:00.000+01:00", "2018-10-18T00:30:00.000+01:00"],
"eventsDateTimes": ["2018-10-18T22:00:00.000+02:00", "2018-10-31T00:30:00.000+01:00", "2018-11-08T20:00:00.000+01:00"],
"eventsDateTimes2": [],
}
""".data(using: .utf8)!
let decoder : JSONDecoder = JSONDecoder.myDefaultJsonDecoder
let date = try decoder.decode(DateDemo.self, from: json)
print(date.dates)
print(date.eventsDateTimes)
print(date.eventsDateTimes2)
// It prints out:
// [2018-10-17 22:00:00 +0000, 2018-10-17 23:30:00 +0000]
// Optional([2018-10-18 20:00:00 +0000, 2018-10-30 23:30:00 +0000, 2018-11-08 19:00:00 +0000])
// Optional([])
}
func testDateDecodingWithHierarchy() throws {
let json = """
{
"dates": ["2018-10-17T23:00:00.000+01:00", "2018-10-18T00:30:00.000+01:00"],
"eventsDateTimes": ["2018-10-18T22:00:00.000+02:00", "2018-10-31T00:30:00.000+01:00", "2018-11-08T20:00:00.000+01:00"],
"eventsDateTimes2": [],
"eventsDateTimes3": ["2018-10-18T22:00:00.000+02:00", "2018-10-31T00:30:00.000+01:00", "2018-11-08T20:00:00.000+01:00"],
}
""".data(using: .utf8)!
let decoder : JSONDecoder = JSONDecoder.myDefaultJsonDecoder
let date = try decoder.decode(DateDemo2.self, from: json)
print(date.dates)
print(date.eventsDateTimes)
print(date.eventsDateTimes2)
print(date.eventsDateTimes3)
// It prints out:
// [2018-10-17 22:00:00 +0000, 2018-10-17 23:30:00 +0000]
// Optional([2018-10-18 20:00:00 +0000, 2018-10-30 23:30:00 +0000, 2018-11-08 19:00:00 +0000])
// Optional([])
// nil ---> ??? Why is this nil?
assert(date.eventsDateTimes3 != nil, "eventsDateTimes3 must not be nil")
}
}
extension JSONDecoder {
static var myDefaultJsonDecoder: JSONDecoder {
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(DateFormatter.myDefaultDateFormatter)
return decoder
}
}
extension DateFormatter {
static var myDefaultDateFormatter: DateFormatter {
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZZ"
return formatter
}
}
值。
url
如何恢复render.onload和// service
export class UploadService {
constructor(private alertService: AlertService) {}
uploadPhoto(event: Event) {
const file = (event.target as HTMLInputElement).files[0];
if (file.type === 'image/png' || file.type === 'image/jpeg' || file.type === 'image/jpg') {
const reader = new FileReader();
let url;
reader.onload = () => {
url = reader.result;
};
reader.onerror = (error: any) => {
this.alertService.error(`Error ao carregar a imagem: ${error}`);
return;
};
reader.readAsDataURL(file);
return { File: file, Url: url };
} else {
this.alertService.error('Formato inválido. Somente imagens do formato Png, Jpeg e Jpg são permitidos.');
return;
}
}
}
// component
uploadBanner(event: Event) {
const Upload = this.uploadService.uploadPhoto(event);
if (Upload) {
this.urlBanner = Upload.Url;
this.shop.banner = Upload.File;
}
}？
答案 0 :(得分：1)
您将其视为同步操作，但事实并非如此。您必须使用Promise或Observable来解决此问题。并在您的onload事件触发时返回数据。
export class UploadService {
constructor(private alertService: AlertService) {}
uploadPhoto(event: Event): Promise<{file: any, url: string}> { {
return new Promise((resolve, reject) => {
const file = (event.target as HTMLInputElement).files[0];
if (file.type === 'image/png' || file.type === 'image/jpeg' || file.type === 'image/jpg') {
const reader = new FileReader();
let url;
reader.onload = () => {
resolve({file, url: reader.result})
};
reader.onerror = (error: any) => {
this.alertService.error(`Error ao carregar a imagem: ${error}`);
reject(error)
};
reader.readAsDataURL(file);
} else {
let error = 'Formato inválido. Somente imagens do formato Png, Jpeg e Jpg são permitidos.'
this.alertService.error(error);
reject(error);
}
}
}
}
组件
// component
uploadBanner = async (event: Event) => {
const url = await this.uploadService.uploadPhoto(event);
console.log(url)
}