Can I use layout_weight to position a RelativeLayout?

I've been trying all day to get this to work and i think that I can use RelativeLayout

android:layout_weight="0.3"  

to place three buttons on the right side of the screen, not centered but 30% down from the top.

Is this possible and if so how do I do it?

The following is my XML that shows three buttons underneath each other but in top right position:

   </RelativeLayout>
      <LinearLayout
        android:id="@+id/rightRelativeLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_weight="1"
        android:orientation="vertical"
        >
            <ImageButton
                android:id="@+id/btn_A" 
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="A"
                android:src="@drawable/drawer_1"
                android:background="@android:color/transparent"


 开发者_如何学运维           /> 
            <ImageButton
                android:id="@+id/btn_B" 
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:layout_weight="1"
                android:text="B"
                android:src="@drawable/drawer_1"
                android:background="@android:color/transparent"

                android:layout_below="@+id/btn_A"
            />
            <ImageButton
                android:id="@+id/btn_C" 
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:layout_marginTop="10dp"
                android:text="C"
                android:src="@drawable/drawer_1"
                android:background="@android:color/transparent"

                android:layout_below="@+id/btn_B"

            />
        </LinearLayout>

[UPDATE] Added final working version for people who need it

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout android:id="@+id/RelativeLayout1"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical">

    <Gallery xmlns:android="http://schemas.android.com/apk/res/android"
             android:id="@+id/examplegallery" 
             android:layout_width="fill_parent"
             android:layout_height="wrap_content" />
   <RelativeLayout 
        android:id="@+id/InnerRelativeLayout"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true" >
    <Button 
        android:id="@+id/btn_newpen_drawtext" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Pen"
    />      
    <EditText 
        android:id="@+id/etx_addtext_drawtext"
        android:layout_width="fill_parent"
        android:layout_toLeftOf="@+id/btn_delete_pen"
        android:layout_toRightOf="@+id/btn_newpen_drawtext"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:text=""
    />
        <Button 
            android:id="@+id/btn_delete_pen" 
            android:layout_toLeftOf="@+id/btn_save_drawtext"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Del"
        />
        <Button 
            android:id="@+id/btn_save_drawtext" 
            android:layout_alignParentRight="true" 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="save"
        />

   </RelativeLayout>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rightLinerLayoutL0"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:layout_toRightOf="@+id/RelativeLayout1"
    android:weightSum="1.0"
    android:layout_alignParentRight="true"
    android:orientation="vertical"
    >
    <LinearLayout android:layout_height="0dp" 
                  android:id="@+id/rightLinerLayoutL1" 
                  android:layout_weight="0.15" 
                  android:layout_width="0dp">
    </LinearLayout>
    <LinearLayout android:layout_height="0dp" 
                  android:orientation="vertical" 
                  android:id="@+id/rightLinerLayoutL2" 
                  android:layout_weight="0.85" 
                  android:layout_width="wrap_content">

        <ImageButton android:text="Button_A" 
            android:background="@android:color/transparent" 
            android:layout_height="wrap_content" 
            android:id="@+id/btn_A" 
            android:layout_width="wrap_content" 
            android:layout_gravity="right" 
            android:src="@drawable/drawer"
            android:onClick="btnAListener">
        </ImageButton>
        <ImageButton android:text="Button_B" 
            android:background="@android:color/transparent" 
            android:layout_height="wrap_content" 
            android:layout_marginTop="10dp"
            android:id="@+id/btn_B" 
            android:layout_width="wrap_content" 
            android:layout_gravity="right" 
            android:src="@drawable/drawer"
            android:onClick="btnBListener">
        </ImageButton>
        <ImageButton android:text="Button_C" 
            android:background="@android:color/transparent" 
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:id="@+id/btn_C" 
            android:layout_width="wrap_content" 
            android:layout_gravity="right" 
            android:src="@drawable/drawer"
            android:onClick="btnCListener">
        </ImageButton>
    </LinearLayout>
</LinearLayout >

</RelativeLayout>

Stack 2 LinearLayout (L1, L2) sections with weights of 0.3 and 0.7 (and heights of 0dp) inside a LinearLayout (L0) with vertical orientation and total weight of 1.0. Put your buttons in the 0.7 weighted layout (L2). That will give you your spacing of 30% above the buttons.

You can then place the containing LinearLayout (L0) inside a RelativeLayout (R0) and place L0 relative to the right of the parent (R0), which will position the entire thing on the right side of the screen.

Edit: My version is pretty much same as Milde in end, except using a root of RelativeLayout so I could put the layout_alignParentRight="true" to ensure it's flush to the right. The only sticking point I found was ensuring your first LinearLayout has height of fill_parent so that your spacer really is 30% of screen.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent">
    <LinearLayout android:orientation="vertical" android:layout_height="fill_parent" android:layout_width="wrap_content" android:weightSum="1.0" android:layout_alignParentRight="true">
        <LinearLayout android:layout_weight="0.3" android:layout_height="0dp" android:layout_width="0dp" />
        <LinearLayout android:layout_weight="0.7" android:layout_height="0dp" android:layout_width="wrap_content" android:orientation="vertical">
            <Button android:text="Button 1" android:layout_width="wrap_content" android:layout_height="wrap_content" />
            <Button android:text="Button 2" android:layout_width="wrap_content" android:layout_height="wrap_content" />
            <Button android:text="Button 3" android:layout_width="wrap_content" android:layout_height="wrap_content" />
        </LinearLayout>
    </LinearLayout>
</RelativeLayout>

Try this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rightLinerLayoutL0"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    >
    <LinearLayout android:id="@+id/rightLinerLayoutL1" android:layout_weight="0.3" android:layout_width="fill_parent">
    </LinearLayout>
    <LinearLayout android:orientation="vertical" android:id="@+id/rightLinerLayoutL2" android:layout_weight="0.7" android:layout_width="fill_parent">
        <Button android:text="Button_A" android:layout_height="wrap_content" android:id="@+id/btn_A" android:layout_width="wrap_content" android:layout_gravity="right"></Button>
        <Button android:text="Button_B" android:layout_height="wrap_content" android:id="@+id/btn_B" android:layout_width="wrap_content" android:layout_gravity="right"></Button>
        <Button android:text="Button_C" android:layout_height="wrap_content" android:id="@+id/btn_C" android:layout_width="wrap_content" android:layout_gravity="right"></Button>
    </LinearLayout>
</LinearLayout >

Since this xml file doesn't give error it doesn't mean that you can use these attributes (weight, orientation associated to LinearLayout) with RelativeLayout. Please see the documentation for RelativeLayout first.