Why do I keep having problems with R not being resolved?

I have constantly gotten the same error over and over in my program and i can't find out how to fix it. R cann开发者_StackOverflowot be resolved to an error. I have tried to build my project and i have no imports that involve .R? Would anyone know how to fix it?

Here's my xml files i can't seem to find anything wrong....

strings.xml Remote Doc Remote Doc Patient Mode Doctor Mode About Exit Simple Mode Detailed Mode About Remote Doc \ Remote Doc is an application that allows a brace user analyze how often they use their thing

main.xml

    <!-- Patient Option -->
    <Button android:layout_width="fill_parent"
            android:layout_height="wrap_content" 
            android:layout_weight="1"
        android:text="@string/patientButton"
        android:id="@+id/patientButton">
    </Button>

    <!-- Doctor Option -->
    <Button android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:text="@string/doctorButton"
        android:layout_weight="1"
        android:id="@+id/doctorButton">
    </Button>

    <!-- Exit Mode -->
    <Button android:text="@string/exit" 

     android:layout_weight="1"
     android:id="@+id/exit" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content"></Button>

     <!-- About Mode -->
    <Button android:text="@string/aboutButton" 

     android:layout_weight="1"
     android:id="@+id/aboutButton" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content"></Button>
</LinearLayout>


/>

main.xml- land

    android:text="@string/mainTitle"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_gravity="center"
    android:layout_marginBottom="20dip"
    android:textSize="24.5sp"/>
    <TableLayout
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:layout_gravity="center"
        android:stretchColumns="*">
        <TableRow> 
            <Button
                android:text="@string/patientButton"
                android:id="@+id/patientButton"/>
            <Button
                android:text="@string/doctorButton"
                android:id="@+id/doctorButton"/>    
        </TableRow>
        <TableRow>
            <Button
                android:text="@string/aboutButton"
                android:id="@+id/aboutButton"/>
            <Button
                android:text="@string/exit"
                android:id="@+id/exit"/>    
        </TableRow>
    </TableLayout>
</LinearLayout>

---

This is a really common problem. First try cleaning your project by going to Project > Clean.

If that doesn't work, try one of the recommendations from this similar question

---

R is an automatically generated class in Android. It holds all your ressource references. Since the creation of that failed, you will most likely have an error inside one of your ressource files. (e.g. syntax error in a layout file like main.xml, or in your strings.xml). Check these files inside the res/ folder. Probably in the one you most recently edited.

After your are done and found it, this should go away automatically. Sometimes it gets stuck though, then do a project clean. Inside eclipse select Project->Clean.