這段時(shí)間的主業(yè)是完成一個(gè)家政類小程序,終于是過審核發(fā)布了。不得不說微信的這個(gè)小程序生態(tài)還是頗有想法的,拋開他現(xiàn)有的一些問題不說,其提供的組件系統(tǒng)乍一看還是蠻酷的。比如其提供的一個(gè)叫swiper的視圖組件,就可以在寫界面的時(shí)候省不少時(shí)間和代碼,輪播圖片跟可滑動(dòng)列表都可以用。導(dǎo)致現(xiàn)在回來寫angular項(xiàng)目時(shí)也想整一個(gè)這樣的組件出來,本文就將使用angular的組件能力和服務(wù)能力完成這么一個(gè)比較通用,耦合度較低的swiper出來。
目前成都創(chuàng)新互聯(lián)公司已為成百上千的企業(yè)提供了網(wǎng)站建設(shè)、域名、網(wǎng)站空間、網(wǎng)站托管、服務(wù)器托管、企業(yè)網(wǎng)站設(shè)計(jì)、蓬安網(wǎng)站維護(hù)等服務(wù),公司將堅(jiān)持客戶導(dǎo)向、應(yīng)用為本的策略,正道將秉承"和諧、參與、激情"的文化,與客戶和合作伙伴齊心協(xié)力一起成長,共同發(fā)展。
首先要選擇使用的技術(shù),要實(shí)現(xiàn)的是與界面打交道的東西,自然是實(shí)現(xiàn)成一個(gè)組件,最終要實(shí)現(xiàn)的效果是寫下這樣的代碼就可以完成一個(gè)可以滑動(dòng)的視圖來:
<swipers> <swiper>視圖1</swiper> <swiper>視圖2</swiper> </swipers>
然后要把最基本的組件定義寫出來,顯然這里要定義兩個(gè)組件。第一個(gè)是父級(jí)組件,選擇器名字就叫ytm-swipers,目前做的事情僅僅是做一個(gè)外殼定義基本樣式,使用時(shí)的子標(biāo)簽都會(huì)插入在ng-content標(biāo)簽中。
@Component({ selector: 'ytm-swipers', template: ` <div class="view-body"> <ng-content></ng-content> </div> `, styles: [` .view-body{height: 100%;width: 100%;overflow: hidden;position: relative;} `] })
第二個(gè)就是子視圖了,在父級(jí)組件下,每個(gè)子組件都會(huì)沾滿父級(jí)組件,只有當(dāng)前的子組件會(huì)顯示,當(dāng)切換視圖時(shí)實(shí)際做的就是更改這些子組件的顯示方式,說的最簡單的話,這個(gè)子組件還是僅僅用來加一個(gè)子外殼,給外殼添加基本樣式,實(shí)際的頁面內(nèi)容原封不動(dòng)放在ng-content標(biāo)簽中。
@Component({ selector: 'swiper', template: ` <div class="view-child" *ngIf="swiper.displayList.indexOf(childId) >= 0" [ngClass]="{'active': swiper.displayList[0] === childId, 'prev': swiper.displayList[2] === childId, 'next': swiper.displayList[1] === childId}"> <ng-content></ng-content> </div> `, styles: [` .view-child{ height: 100%;width: 100%;position: absolute;top: 0; transition: 0.5s linear;background: #fff; overflow-x: hidden; } .view-child.active{left: 0;z-index: 9;} .view-child.next{left: 100%;z-index: 7;} .view-child.prev{left: -100%;z-index: 8;} `] })
下一步是要讓這兩個(gè)父子組件完成心靈的溝通,講道理其實(shí)可以直接使用ElementRef強(qiáng)行取到DOM來操作,不過這里使用的是組件內(nèi)服務(wù)。和普通的服務(wù)使用上沒差別,不過其provider是聲明在某個(gè)組件里的,所以此服務(wù)只有在此組件以及子組件中可以注入使用。
@Injectable() class SwiperService { public swiperList: number[]; public displayList: number[]; // 0為當(dāng)前 1為下一個(gè) 2為上一個(gè) public current: number; private changing: boolean; constructor() { this.changing = false; this.swiperList = []; this.displayList = []; this.current = 0; } public Add(id: number) { this.swiperList.push(id); switch (this.swiperList.length) { case 1: this.displayList[0] = id; return; case 2: this.displayList[1] = id; return; default: this.displayList[2] = id; return; } } public Next(): Promise<any> { if (this.changing) { return new Promise<any>((resolve, reject) => { return reject('on changing'); }); } this.changing = true; let c = this.swiperList.indexOf(this.displayList[0]); let n = this.swiperList.indexOf(this.displayList[1]); let p = this.swiperList.indexOf(this.displayList[2]); p = c; c = n; n = (c + 1) % this.swiperList.length; this.displayList[0] = this.swiperList[c]; this.displayList[2] = this.swiperList[p]; this.displayList[1] = -1; setTimeout(() => { this.displayList[1] = this.swiperList[n]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } public Prev(): Promise<any> { if (this.changing) { return new Promise<any>((resolve, reject) => { return reject('on changing'); }); } this.changing = true; let c = this.swiperList.indexOf(this.displayList[0]); let n = this.swiperList.indexOf(this.displayList[1]); let p = this.swiperList.indexOf(this.displayList[2]); n = c; c = p; p = p - 1 < 0 ? this.swiperList.length - 1 : p - 1; this.displayList[0] = this.swiperList[c]; this.displayList[1] = this.swiperList[n]; this.displayList[2] = -1; setTimeout(() => { this.displayList[2] = this.swiperList[p]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } public Skip(index: number): Promise<any> { let c = this.swiperList.indexOf(this.displayList[0]); if (this.changing || c === index) { return new Promise<any>((resolve, reject) => { reject('on changing or no change'); }); } this.changing = true; let n = (index + 1) % this.swiperList.length; let p = index - 1 < 0 ? this.swiperList.length - 1 : index - 1; this.displayList[0] = this.swiperList[index]; if (index > c) { this.displayList[2] = this.swiperList[p]; this.displayList[1] = -1; setTimeout(() => { this.displayList[1] = this.swiperList[n]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } else { this.displayList[1] = this.swiperList[n]; this.displayList[2] = -1; setTimeout(() => { this.displayList[2] = this.swiperList[p]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } } }
用到的變量包括: changing變量保證同時(shí)只能進(jìn)行一個(gè)切換,保證切換完成才能進(jìn)行下一個(gè)切換;swiperList裝填所有的視圖的id,這個(gè)id在視圖初始化的時(shí)候生成;displayList數(shù)組只會(huì)有三個(gè)成員,裝填的依次是當(dāng)前視圖在swiperList中的索引,下一個(gè)視圖的索引,上一個(gè)視圖的索引;current變量用戶指示當(dāng)前顯示的視圖的id。實(shí)際視圖中的顯示的控制就是使用ngClass指令來根據(jù)displayList和視圖id附加相應(yīng)的類,當(dāng)前視圖會(huì)正好顯示,前一視圖會(huì)在左邊剛好遮擋,后一視圖會(huì)在右邊剛好遮擋。
同時(shí)服務(wù)還要提供幾個(gè)方法:Add用于添加制定id的視圖,Next用于切換到下一個(gè)視圖(左滑時(shí)調(diào)用),Prev用于切換到前一個(gè)視圖(右滑時(shí)調(diào)用),再來一個(gè)Skip用于直接切換到指定id的視圖。
在子視圖中注入此服務(wù),需要在子視圖初始化時(shí)生成一個(gè)id并Add到視圖列表中:
export class YTMSwiperViewComponent {
public childId: number;
constructor(@Optional() @Host() public swiper: SwiperService) {
this.childId = this.swip
@Injectable() class SwiperService { public swiperList: number[]; public displayList: number[]; // 0為當(dāng)前 1為下一個(gè) 2為上一個(gè) public current: number; private changing: boolean; constructor() { this.changing = false; this.swiperList = []; this.displayList = []; this.current = 0; } public Add(id: number) { this.swiperList.push(id); switch (this.swiperList.length) { case 1: this.displayList[0] = id; return; case 2: this.displayList[1] = id; return; default: this.displayList[2] = id; return; } } public Next(): Promise<any> { if (this.changing) { return new Promise<any>((resolve, reject) => { return reject('on changing'); }); } this.changing = true; let c = this.swiperList.indexOf(this.displayList[0]); let n = this.swiperList.indexOf(this.displayList[1]); let p = this.swiperList.indexOf(this.displayList[2]); p = c; c = n; n = (c + 1) % this.swiperList.length; this.displayList[0] = this.swiperList[c]; this.displayList[2] = this.swiperList[p]; this.displayList[1] = -1; setTimeout(() => { this.displayList[1] = this.swiperList[n]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } public Prev(): Promise<any> { if (this.changing) { return new Promise<any>((resolve, reject) => { return reject('on changing'); }); } this.changing = true; let c = this.swiperList.indexOf(this.displayList[0]); let n = this.swiperList.indexOf(this.displayList[1]); let p = this.swiperList.indexOf(this.displayList[2]); n = c; c = p; p = p - 1 < 0 ? this.swiperList.length - 1 : p - 1; this.displayList[0] = this.swiperList[c]; this.displayList[1] = this.swiperList[n]; this.displayList[2] = -1; setTimeout(() => { this.displayList[2] = this.swiperList[p]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } public Skip(index: number): Promise<any> { let c = this.swiperList.indexOf(this.displayList[0]); if (this.changing || c === index) { return new Promise<any>((resolve, reject) => { reject('on changing or no change'); }); } this.changing = true; let n = (index + 1) % this.swiperList.length; let p = index - 1 < 0 ? this.swiperList.length - 1 : index - 1; this.displayList[0] = this.swiperList[index]; if (index > c) { this.displayList[2] = this.swiperList[p]; this.displayList[1] = -1; setTimeout(() => { this.displayList[1] = this.swiperList[n]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } else { this.displayList[1] = this.swiperList[n]; this.displayList[2] = -1; setTimeout(() => { this.displayList[2] = this.swiperList[p]; this.changing = false; }, 500); return new Promise<any>((resolve, reject) => { return resolve(this.displayList[0]); }); } } } er.swiperList.length;
this.swiper.Add(this.swiper.swiperList.length);
}
}
這個(gè)id其實(shí)就是已有列表的索引累加,且一旦有新視圖被初始化,都會(huì)添加到列表中(支持動(dòng)態(tài)加入很酷,雖然不知道會(huì)有什么隱藏問題發(fā)生)。
父組件中首先必須要配置一個(gè)provider聲明服務(wù):
@Component({ selector: 'ytm-swipers', template: ` <div class="view-body"> <ng-content></ng-content> </div> `, styles: [` .view-body{height: 100%;width: 100%;overflow: hidden;position: relative;} `], providers: [SwiperService] })
然后就是要監(jiān)聽手勢滑動(dòng)事件,做出相應(yīng)的切換。以及傳入一個(gè)current變量,每當(dāng)此變量更新時(shí)都要切換到對(duì)應(yīng)id的視圖去,實(shí)際使用效果就是:
<ytm-swipers [current]="1">...</ytm-swipers>
可以將視圖切換到id喂1的視圖也就是第二個(gè)視圖。
export class YTMSwiperComponent implements OnChanges { @Input() public current: number; @Output() public onSwiped = new EventEmitter<Object>(); private touchStartX; private touchStartY; constructor(private swiper: SwiperService) { this.current = 0; } public ngOnChanges(sc: SimpleChanges) { if (sc.current && sc.current.previousValue !== undefined && sc.current.previousValue !== sc.current.currentValue) { this.swiper.Skip(sc.current.currentValue).then((id) => { console.log(id); this.onSwiped.emit({current: id, bySwipe: false}); }).catch((err) => { console.log(err); }); } } @HostListener('touchstart', ['$event']) public onTouchStart(e) { this.touchStartX = e.changedTouches[0].clientX; this.touchStartY = e.changedTouches[0].clientY; } @HostListener('touchend', ['$event']) public onTouchEnd(e) { let moveX = e.changedTouches[0].clientX - this.touchStartX; let moveY = e.changedTouches[0].clientY - this.touchStartY; if (Math.abs(moveY) < Math.abs(moveX)) { /** * Y軸移動(dòng)小于X軸 判定為橫向滑動(dòng) */ if (moveX > 50) { this.swiper.Prev().then((id) => { // this.current = id; this.onSwiped.emit({current: id, bySwipe: true}); }).catch((err) => { console.log(err); }); } else if (moveX < -50) { this.swiper.Next().then((id) => { // this.current = id; this.onSwiped.emit({current: id, bySwipe: true}); }).catch((err) => { console.log(err); }); } } this.touchStartX = this.touchStartY = -1; } }
此外代碼中還添加了一個(gè)回調(diào)函數(shù),可以再視圖完成切換時(shí)執(zhí)行傳入的回調(diào),這個(gè)使用的是angular的EventEmitter能力。
以上就是全部實(shí)現(xiàn)了,實(shí)際的使用示例像這樣:
<ytm-swipers [current]="0" (onSwiped)="切換回調(diào)($event)"> <swiper> 視圖1 </swiper> <swiper> 視圖2 </swiper> <swiper> 視圖3 </swiper> </ytm-swipers>
視圖的切換有了兩種方式,一是手勢滑動(dòng),不過沒有寫實(shí)時(shí)拖動(dòng),僅僅是判斷左右滑做出反應(yīng)罷了,二是更新[current]節(jié)點(diǎn)的值。
整個(gè)組件的實(shí)現(xiàn)沒有使用到angular一些比較底層的能力,僅僅是玩弄css樣式以及組件嵌套并通過服務(wù)交互,以及Input、Output與外界交互。相比之下ionic的那些組件就厲害深?yuàn)W多了,筆者還有很長的路要走。
以上所述是小編給大家介紹的基于angular實(shí)現(xiàn)模擬微信小程序swiper組件,希望對(duì)大家有所幫助,如果大家有任何疑問歡迎給我留言小編會(huì)及時(shí)回復(fù)大家的!
文章題目:基于angular實(shí)現(xiàn)模擬微信小程序swiper組件
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