ionic4离子选择占位符的不透明度不能更改

Question

无法更改离子v4中的占位符不透明度

我试图在global.css中更改离子选择占位符的不透明度

以下是我的代码

.select-placeholder {
opacity：1; }

but that didn't works , even i tried all methods to change it's css like

ion-select{
        --placeholder-opacity: 1 !important;
    }
    ion-select{
         --opacity: 1 !important;
    }
    ion-select{
        opacity: 1 !important;
    }

etc... but not works fine , event it color change very well using following code 

   ion-select{
         color: var(--ion-color-secondary);
    }

no change , it took default opacity <style> tag.

任何帮助，将不胜感激

已编辑

<ion-select class="contact-us-select" interface="alert" [interfaceOptions]="customPopoverOptions"
        placeholder="selection" cancelText="cancel" okText="done" (ionChange)="onSelectChangevalue($event)">
        <ion-select-option *ngFor="let item of Data" [value]="item.id">{{item?.title}}</ion-select-option>
      </ion-select>

Answer 1

ion-select{
    --placeholder-opacity: 1 !important;
    color:black;
}

Answer 2

全局.scss

ion-select{
     opacity: 0.3 !important;
     color: var(--ion-color-secondary);
}

这应该可以很好地更改全局 scss，您只需要--更改组件中定义的 scss 变量。