how to check for input validation java
<p>this is what i have so far, how do i make it so it will check the the EditText boxes are empty. when i test it out with all empty boxes it will force close, why and/or how do I fix it?</p>

<pre><code>if ((x1field.getText().toString().equals("")));
{
forgetunits.setText("you have forgotten a number");
    }
if ((x2field.getText().toString().equals("")));
{
forgetunits.setText("you have forgotten a number");
    }
if ((y1field.getText().toString().equals("")));
{
    forgetunits.setText("you have forgotten a number");
    }
if ((y2field.getText().toString().equals("")));
{
        forgetunits.setText("you have forgotten a number");
        }
</code></pre>
