Android : check if (numberDecimal) edittext is empty/null

My app crashes although the code seems correct :-O if I don't insert anything to editText1 app crashes

<EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="18dp"
        android:ems="10"
        android:inputType="numberDecimal" >

        String tmp1 = editText1.getText().toString().trim();
                if(tmp1.isEmpty() || tmp1.length() == 0 || tmp1.equals("") || tmp1 == null){
                    editText1.setError("error");
                }
                else