ngClass正在跳过一些类，并且只对true应用一个类

Question

ngClass仅应用前三行中的一个类，并将在最后一行应用所有类：

  <ion-list id="wifiList-list2">
      <ion-item color="none" id="wifiList-list-item1" *ngFor="let wifi of wifi_list" on-click="goToSSID(wifi)">
       <!-- <ion-icon name="wifi" item-left></ion-icon> -->
        <div
          [ngClass]="{
            'signal-bars mt1 sizing-box good four-bars' : (wifi.level) < '0' && (wifi.level) > '-60',
            'signal-bars mt1 sizing-box four-bars bad one-bar' : (wifi.level) <= '-70' && (wifi.level) > '-90',
            'signal-bars mt1 sizing-box four-bars bad two-bars' : (wifi.level) <= '-67' && (wifi.level) > '-70',
            'signal-bars mt1 sizing-box four-bars ok three-bars' : (wifi.level) <= '-60' && (wifi.level) > '-67'
          }"
          >
          <div class="first-bar bar"></div>
          <div class="second-bar bar"></div>
          <div class="third-bar bar"></div>
          <div class="fourth-bar bar"></div>
        </div>
      </ion-item>
    </ion-list>

在下面的屏幕截图中，任何值为-35的wifi.level将仅适用于一个“好”类并跳过其余部分。任何值为-63的wifi.level都适用于所有类：“signal-bars mt1 sizing-box four-bars ok three-bars”

与上面的截图相同，wifi.level = -73仅适用于“坏”类。

删除' '和( )时，我的结果相同：

<ion-list id="wifiList-list2">
  <ion-item color="none" id="wifiList-list-item1" *ngFor="let wifi of wifi_list" on-click="goToSSID(wifi)">
   <!-- <ion-icon name="wifi" item-left></ion-icon> -->
    <div
      [ngClass]="{
        'signal-bars mt1 sizing-box good four-bars' : wifi.level < 0 && wifi.level > -60,
        'signal-bars mt1 sizing-box four-bars bad one-bar' : wifi.level <= -70 && wifi.level > -90,
        'signal-bars mt1 sizing-box four-bars bad two-bars' : wifi.level <= -67 && wifi.level > -70,
        'signal-bars mt1 sizing-box four-bars ok three-bars' : wifi.level <= -60 && wifi.level > -67
      }"
      >
      <div class="first-bar bar"></div>
      <div class="second-bar bar"></div>
      <div class="third-bar bar"></div>
      <div class="fourth-bar bar"></div>
    </div>
  </ion-item>
</ion-list>

Answer 1

将wifi.level的值与没有''的数字进行比较。

如果这对您有用，请告诉我。