checking whether or not a variable of type double is null or not, generates error
<p>I'm just checking if a value of a double variable is null or not, strangely, an error 
raised saying "operator == is undefined for double"?</p>

<p><strong>Code</strong>:</p>

<pre><code>public double getGyro_X() {
    if (this.gyro_X == null) {
        Toast.makeText(this, ""+gyro_XIsNullText, ToastdurationShort).show();
    } else {
    return this.gyro_X;
    }
}
</code></pre>
