angular - Material Angular 选择所有复选框

Question

我正在尝试在 Angular Material 上实现全选复选框。当用户点击特定的复选框(项目)时，主复选框应显示Indeterminate，如果所有复选框都被选中，则变为checked。目前我有一些奇怪的行为。任何人都可以让我知道我哪里出错了吗？这是 stackblitz . 这是我的示例代码:

应用.html

<fieldset class="demo-fieldset">
  <div>
    <mat-checkbox aria-label="Select All" [checked]="isChecked(selected3, itemsObject)" [indeterminate]="isIndeterminate(selected3, itemsObject)" (click)="toggleAll(selected3, itemsObject)">
      Select All list of user (Array of objects) {{isChecked(selected3, itemsObject)}}
    </mat-checkbox>
  </div>
  <div class="demo-select-all-checkboxes" *ngFor="let item of itemsObject">
    <mat-checkbox [checked]="exists(item, selected3)" (click)="toggle(item, selected3)">
      {{ item.val }}
    </mat-checkbox>
    {{exists(item, selected3)}}

  </div>
</fieldset>

应用.ts

import {
  Component
} from '@angular/core';

@Component({
  selector: 'app',
  templateUrl: 'app.html',
  styleUrls: ['app.css'],
})
export class CheckboxConfigurableExample {
  itemsObject = [{
    id: 1,
    val: 'john'
  }, {
    id: 2,
    val: 'jane'
  }];
  selected3 = [];

  toggle(item, list) {
    var idx = list.indexOf(item);
    if (idx > -1) {
      list.splice(idx, 1);
    } else {
      list.push(item);
    }
  }

  exists(item, list) {
    return list.indexOf(item) > -1;
  };

  isIndeterminate(x, t) {
    return (x.length !== 0 && x.length !== t.length);
  };

  isChecked(x, t) {
    return x.length === t.length;
  };

  toggleAll(x, t) {
    var l1 = x.length,
      l2 = t.length;
    if (l1 === l2) {
      x.splice(0, l1);
    } else if (l1 === 0 || l1 > 0) {
      //First we need to empty array, because we are using push to fill in array
      x.splice(0, l2);
      t.forEach(y => x.push(y));
    }
  };
}

这是我的 stackblitz

Answer 1

试试这段代码:

组件:

import {Component} from '@angular/core';
import {

  MatCheckboxChange
} from '@angular/material';

/**
 * @title Configurable checkbox
 */
@Component({
  selector: 'checkbox-configurable-example',
  templateUrl: 'checkbox-configurable-example.html',
  styleUrls: ['checkbox-configurable-example.css'],
})
export class CheckboxConfigurableExample {
  itemsObject = [{
    id: 1,
    val: 'john'
  }, {
    id: 2,
    val: 'jane'
  }];
  selected3 = [];

  toggle(item,event: MatCheckboxChange) {
     if (event.checked) {
      this.selected3.push(item);
    } else {
      const index = this.selected3.indexOf(item);
      if (index >= 0) {
        this.selected3.splice(index, 1);
      }
    }
   console.log(item + "<>", event.checked);
  }

  exists(item) {
    return this.selected3.indexOf(item) > -1;
  };

  isIndeterminate() {
    return (this.selected3.length > 0 && !this.isChecked());
  };

  isChecked() {
    return this.selected3.length === this.itemsObject.length;
  };



  toggleAll(event: MatCheckboxChange) { 

    if ( event.checked ) {

       this.itemsObject.forEach(row => {
          // console.log('checked row', row);
          this.selected3.push(row)
          });

        // console.log('checked here');
    } else {
      // console.log('checked false');
       this.selected3.length = 0 ;
    }
}
}

模板:

<fieldset class="demo-fieldset">
  <div>
     <mat-checkbox aria-label="Select All" [checked]="isChecked()" [indeterminate]="isIndeterminate()" (change)="$event ? toggleAll($event) : null">
      Select All list of user (Array of objects) {{isChecked(selected3)}}
    </mat-checkbox>
  </div>
  <div class="demo-select-all-checkboxes" *ngFor="let item of itemsObject">
    <mat-checkbox (click)="$event.stopPropagation()"
                    (change)="$event ? toggle(item, $event) : null"
                    [checked]="exists(item)">
      {{ item.val }}
    </mat-checkbox>
    {{exists(item)}}

  </div>
</fieldset>