angular实现简单的pagination分页组件

不想使用第三方库，只想使用一个分页器，那么就简单的实现一个，效果如下：

1.使用方式：

---

<custom-pagination *ngIf="enterpriseList.length"
                         [fastTurnBtn]="false"
                         [totalPage]="paginationParams.totalPages"
                         [maxSize]="paginationParams.maxSize"
                         [(ngModel)]="paginationParams.currentPage"
                         (changePage)="changePage($event)">
      </custom-pagination>

2.可配置项：

---

• fsatTurnBtn：是否显示首页和末页
• turnBtn：是否显示上下翻页
• maxSize：最多显示几页
• totalPage：总页数
• moreBtn：是否显示省略号提示更多分页

3.实现方案：

---

先上代码，这里使用啦ngModel实现自定义组件的数据双向绑定，可以看上一篇随记的介绍：

// custom-pagination.ts

import { Component, OnInit, Input, Output, EventEmitter, OnChanges, forwardRef  } from '@angular/core';
import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';

@Component({
  selector: 'custom-pagination',
  templateUrl: './pagination.component.html',
  styleUrls: ['./pagination.component.css'],
  providers: [{
    provide: NG_VALUE_ACCESSOR,
    useExisting: forwardRef(() => PaginationComponent),
    multi: true
  }]
})
export class PaginationComponent implements OnInit, OnChanges {

  constructor() { }
  @Input() totalPage: any;
  @Input() maxSize: any = 5;
  @Input() moreBtn: Boolean = true;
  @Input() turnBtn: Boolean = true;
  @Input() fastTurnBtn: Boolean = true;
  @Output() currentPageChange: EventEmitter<Number> = new EventEmitter;
  @Output() changePage: EventEmitter<Number> = new EventEmitter;
  private currentPage = 1;
  showPageList: Array<number> = [];
  showEndPage = 0;
  showBeginPage = 0;
  showLeftMoreStatus = false;
  showRightMoreStatus = false;
  ngOnInit() {
  }
  ngOnChanges () { // 异步获取的数据，在ngOnChange里监听数据变化后再处理分页
    this.initPages();
  }
  currentChange() {
    this.currentPageChange.emit(this.currentPage);
  }
  goToPage (page) {
    if (page && this.currentPage !== page) {
      this.currentPage = page;
      this.changePageHandle();
    }
  }
  prevNextPage (page) {
    console.log(this.currentPage)
    if (this.totalPage < 2) {
      return;
    }
    let pageNum;
    if (page === '上一页') {
      pageNum = this.currentPage === 1 ? this.currentPage : this.currentPage - 1;
    } else {
      pageNum = this.currentPage === this.totalPage ? this.currentPage : this.currentPage + 1;
    }
    if (pageNum !== this.currentPage) {
      this.currentPage = pageNum;
      this.changePageHandle();
    }
  }
  leftMoreClick () { // 左更多按钮点击后处理当前显示的分页
    const startPage = this.showBeginPage - this.maxSize;
    const endPage = startPage + this.maxSize;
    this.currentPage -= Math.ceil((endPage - startPage) / 2);
    this.changePageHandle()
  }
  rightMoreClick () { // 右更多分页按钮点击后处理当前显示的分页
    let startPage;
    if ((this.showEndPage + this.maxSize) < this.totalPage) {
      startPage = this.showEndPage + this.maxSize;
    } else {
      startPage = this.totalPage - this.maxSize;
    }
    const endPage = startPage + this.maxSize;
    this.currentPage += Math.ceil((endPage - startPage) / 2);
    this.changePageHandle()
  }
  formatPages () { // 操作页码后处理需要显示的新页码数据
    if (this.totalPage > this.maxSize) {
      const formatRightPage = this.showEndPage - Math.ceil(this.maxSize / 2); // 需要向后处理显示分页数据的分界点
      const formatLeftPage = this.showBeginPage + Math.floor(this.maxSize / 2); // 需要向前处理显示分页数据的分界点
      let startPage; // 需要显示的开始页码
      if (this.currentPage > formatRightPage || this.currentPage < formatLeftPage) {
        startPage = this.currentPage - Math.floor(this.maxSize / 2) > 0 ? this.currentPage - Math.floor(this.maxSize / 2) : 1;
        this.showBeginPage = startPage;
        this.showEndPage = (startPage + this.maxSize) < this.totalPage ? (startPage + this.maxSize) : this.totalPage;
        if (this.showEndPage - this.showBeginPage <= this.maxSize) { // 如果处理后显示的分页数量少于maxSize，处理需要显示的开始页码满足maxSize
          startPage = this.showEndPage - this.maxSize;
          this.showBeginPage = startPage;
        }
        this.handlePagesData(startPage, this.showEndPage);
      }
    }
    console.log(this.showPageList)
  }
  initPages () { // 根据传入的参数初始化页码
    if (this.totalPage > this.maxSize) {
      this.maxSize--;
      const startPage = this.currentPage;
      this.showBeginPage = startPage;
      this.showEndPage = startPage + this.maxSize;
      this.handlePagesData(startPage, this.showEndPage);
    } else {
      this.showBeginPage = this.currentPage;
      this.showEndPage = this.totalPage;
      for (let i = 1; i <= this.totalPage; i++) {
        this.showPageList.push(i)
      }
    }
    this.showPagesMore();
  }
  handlePagesData (begin, end) { // 循环生成要显示的页码数据
    this.showPageList = [];
    for (let i = begin; i <= end; i++) {
      this.showPageList.push(i)
    }
  }
  showPagesMore () { // 判断是否满足显示向左向右更多分页按钮的条件
    if (this.currentPage > this.maxSize * 2) {
      this.showLeftMoreStatus = true;
    } else {
      this.showLeftMoreStatus = false;
    }
    if (this.showEndPage < this.totalPage) {
      this.showRightMoreStatus = true;
    } else {
      this.showRightMoreStatus = false;
    }
  }
  changePageHandle () { // 翻页后触发方法
    this.formatPages();
    this.showPagesMore();
    this.onModelChange(this.currentPage); // 触发ngModel绑定的数据更新
    this.changePage.emit(this.currentPage); // 向外触发自定义方法，并传值
  }
  onModelChange: Function = () => { };
  // 页面的值改变，调用改方法，并调用onModelChange传入改变后的值，实现值得回传
  writeValue(val): void {
    // 页面初始化时时，调用该方法，传入初始值
    if (val) {
      this.currentPage = val;
    }
  }
  registerOnChange(fn: any): void {
    // 页面值改变时，调用该方法，传入新值实现回传
    this.onModelChange = fn;
  }
  registerOnTouched(fn: any): void {
  }

}

<!--custom-pagination.html-->

<ul class="custom-pagination">
  <li class="page-item first-page" *ngIf="fastTurnBtn" [ngClass]="{'disabled': currentPage === 1}" (click)="goToPage(1)"><span><<</span></li>
  <li class="page-item prev-page" *ngIf="turnBtn" [ngClass]="{'disabled': currentPage === 1}" (click)="prevNextPage('上一页')"><span><</span></li>
  <li class="page-item left-more-page" *ngIf="showLeftMoreStatus && moreBtn" (click)="leftMoreClick()" title="查看更多"><span></span></li>
  <li class="page-item" *ngFor="let item of showPageList" [ngClass]="{'active': currentPage === item}" (click)="goToPage(item)">{{item}}</li>
  <li class="page-item right-more-page" *ngIf="showRightMoreStatus && moreBtn" (click)="rightMoreClick()" title="查看更多"><span></span></li>
  <li class="page-item next-page" *ngIf="turnBtn" [ngClass]="{'disabled': currentPage === totalPage}" (click)="prevNextPage('下一页')"><span>></span></li>
  <li class="page-item last-page" *ngIf="fastTurnBtn" [ngClass]="{'disabled': currentPage === totalPage}" (click)="goToPage(totalPage)"><span>>></span></li>
</ul>

// custom-pagination.css

.custom-pagination{
  overflow: hidden;
  margin: 10px 0;
  text-align: center;
}
.page-item{
  display: inline-block;
  width: 25px;
  height: 25px;
  line-height: 23px;
  border: 1px solid #06a0e7;
  color: #06a0e7;
  text-align: center;
  border-radius: 3px;
  margin: 0 2px;
  cursor: pointer;
  user-select: none;
  vertical-align: middle;
}
.prev-page,.next-page{
  width: auto;
  padding: 0 2px;
}
.page-item.active{
  border-color: #06a0e7;
  background: #06a0e7;
  color: #fff;
}
.disabled{
  cursor: not-allowed;
  border-color: #d9d9d9;
  color: #00000040;
}
.prev-page span,.next-page span,.first-page span,.last-page span{
  display: inline-block;
  transform: scale(.5, 1.2) translateY(-1px);
  min-width: 20px;
}
.left-more-page span,.right-more-page span{
  position: relative;
  display: inline-block;
  width: 100%;
  height: 100%;
}
.left-more-page span:after,.right-more-page span:after{
  position: absolute;
  content: '•••';
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  font-size: 12px;
}
.left-more-page:hover span:after{
  content: '<<';
  transform: scale(.5, 1.2);
}
.right-more-page:hover span:after{
  content: '>>';
  transform: scale(.5, 1.2);
}

以上方案可实现简单的分页器组件，有可以更好的实现方案或者优化实现的，希望指出。