app crashing when ever i'm entering a value-android

I am working on temperature conversion app,

My requirement is i have two text fields Celsius and Fahrenheit 1. when i enter a value in Celsius text field it have to convert into Fahrenheit

and

2. when i enter a value in Fahrenheit text field it have to convert into Celsius

i tried on a single item i.e. when i try on a single field but not both

here goes my code

My XML code.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://ift.tt/nIICcg"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="20dp"
android:orientation="vertical" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Celsius"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
    android:id="@+id/et_cel"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ems="10"
    android:inputType="numberSigned" >

    <requestFocus />
</EditText>

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Forenheit"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
    android:id="@+id/et_for"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ems="10"
    android:inputType="numberSigned" />

<Button
    android:id="@+id/button1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:onClick="go_reset"
    android:text="Reset" />

</LinearLayout>

My java code

EditText cel, fore;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.type3);
    cel = (EditText) findViewById(R.id.et_cel);
    fore = (EditText) findViewById(R.id.et_for);
    cel.addTextChangedListener(new TextWatcher() {

        public void afterTextChanged(Editable s) {
        }

        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
        }

        public void onTextChanged(CharSequence s, int start, int before,
                int count) {

            String inputs = cel.getText().toString();
            if (TextUtils.isEmpty(inputs)) {
                cel.setText("");
            } else {
                try {
                    float i = Float.parseFloat(inputs);
                    i = ((i * 9) / 5) + 32;
                    fore.setText(String.valueOf(i));
                } catch (Exception e) {
                    // TODO: handle exception
                    cel.setText("");
                }

            }
        }
    });

    fore.addTextChangedListener(new TextWatcher() {

        public void afterTextChanged(Editable s) {
        }

        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
        }

        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
            String inputs = fore.getText().toString();
            if (TextUtils.isEmpty(inputs)) {
                cel.setText("");
            } else {
                try {
                    float i = Float.parseFloat(inputs);
                    i = ((i - 32) * 5 / 9);
                    cel.setText(String.valueOf(i));
                } catch (Exception e) {
                    // TODO: handle exception
                    cel.setText("");
                }

            }

        }
    });
}

@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    super.onBackPressed();
    Intent i = new Intent(this, Home.class);
    startActivity(i);
}

public void go_reset(View v) {
    cel.setText("");
    fore.setText("");
}

public void go() {

}