在 Ionic/Angular 中使用 ngIf 时，如何根据按钮的值更改按钮的颜色

Question

I have a html page that generates x number of buttons using ngIf based on a number I feed it earlier in a method call getButton() which is a click listener on the start button.

<ion-content>

  <ion-button (click)="getButton(15)"> 
    Start
  </ion-button>

  <ion-button *ngFor ="let element of buttonArray" (click)="checkAnswer(element.value)"> 
    {{ element.value }}
  </ion-button>

</ion-content>

The value of the button is randomized from an array of colors and then pushed into an array of button values whose length is equal to the number of buttons required.

colorsArray : string[] = ['Red', 'Blue', 'Green', 'Yellow']

getButton(i: number){
    let c: number ;
    for (c=0; c<i; c++) {
      this.buttonArray.push((this.colorsArray[(Math.floor(Math.random()*4))])
    }
   }

The output is x number of buttons with random values from the colorsArray.

How do I change the color of the button to the value of the button (element.value in the code), that is, a button with the value 'red' must be colored 'red' and a button with the value 'blue' must be colored blue.

Answer 1

You Can Generate Random Colors by This Function:

getRandomColor(){
    let color = "#";
    for (let i = 0; i < 3; i++)
    {
        let part = Math.round(Math.random() * 255).toString(16);
        color += (part.length > 1) ? part : "0" + part;
    }
   return color;    
}

and initialize your array with colors:

this.buttonArray.forEach((e)=>{
   e.color = this.getRandomColor();
})

and In html: use ngStyle to show generated color.

<ion-button *ngFor ="let element of buttonArray" (click)="checkAnswer(element.value)" [ngStyle]="{background-color: element.color}"> 
    {{ element.value }}
</ion-button>