android setText

Question

我想计算圆的周长并将结果放在TextView中。

   public void hesapla1(View v){

        double pi = 3.14;
        double yari = R.id.e1;

        double alan = pi * Math.pow(yari,2);

        sonuc1.setText((int) alan);

    }

Answer 1

您只能在String中设置TextView值：

sonuc1.setText(String.valueOf(alan));