Develop Reference

Relative layout doesn't properly display as expected in Landscape view

Hi I'm making my first android program 'a calculator'. I was using the relative layout instead linear layout and I found some problems when it running it in the emulator.
1) the frame has not centered in the screen. 2) Once it is in the landscape mode, the numbers again goes to left side instead of centering it.
I tried many ways but still the problem remains same.
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_centerInParent="true"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:id="#+id/textView2"
android:background="#fbf8c9"
android:editable="true"
android:layout_marginTop="20dp"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1"
android:id="#+id/button"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2"
android:id="#+id/button2"
android:layout_above="#+id/button5"
android:layout_toRightOf="#+id/button"
android:layout_toEndOf="#+id/button"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="3"
android:id="#+id/button3"
android:layout_alignBottom="#+id/button2"
android:layout_toRightOf="#+id/button2"
android:layout_toEndOf="#+id/button2"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="4"
android:id="#+id/button4"
android:layout_below="#+id/button"
android:layout_alignLeft="#+id/button"
android:layout_alignStart="#+id/button"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="5"
android:id="#+id/button5"
android:layout_above="#+id/button8"
android:layout_toLeftOf="#+id/button3"
android:layout_toStartOf="#+id/button3"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="6"
android:id="#+id/button6"
android:layout_below="#+id/button3"
android:layout_toRightOf="#+id/button2"
android:layout_toEndOf="#+id/button2"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="7"
android:id="#+id/button7"
android:layout_below="#+id/button4"
android:layout_alignLeft="#+id/button4"
android:layout_alignStart="#+id/button4"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="8"
android:id="#+id/button8"
android:layout_below="#+id/button4"
android:layout_toLeftOf="#+id/button6"
android:layout_toStartOf="#+id/button6"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="9"
android:id="#+id/button9"
android:layout_alignBottom="#+id/button8"
android:layout_toRightOf="#+id/button8"
android:layout_toEndOf="#+id/button8"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:id="#+id/button10"
android:layout_alignTop="#+id/button12"
android:layout_toLeftOf="#+id/button12"
android:layout_toStartOf="#+id/button12"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:id="#+id/button11"
android:layout_alignTop="#+id/button12"
android:layout_toRightOf="#+id/button12"
android:layout_toEndOf="#+id/button12"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="="
android:id="#+id/button12"
android:layout_below="#+id/button8"
android:layout_alignRight="#+id/button9"
android:layout_alignEnd="#+id/button9"
android:onClick="buttonOnClick"
android:background="#dcfa82" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="*"
android:id="#+id/button13"
android:layout_toRightOf="#+id/button3"
android:layout_alignTop="#+id/button3"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="/"
android:id="#+id/button14"
android:layout_below="#+id/button3"
android:layout_toRightOf="#+id/button6"
android:layout_alignTop="#+id/button6"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="-"
android:id="#+id/button15"
android:layout_toRightOf="#+id/button9"
android:layout_alignTop="#+id/button9"
android:onClick="buttonOnClick" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="AC"
android:id="#+id/button16"
android:layout_alignTop="#+id/button10"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:onClick="buttonOnClick" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:id="#+id/textView1"
android:background="#fbf8c9"
android:editable="true"
android:layout_marginTop="10dp"
android:layout_below="#+id/textView2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RelativeLayout>
</RelativeLayout>
please someone kindly help me in solving this issue..

I would suggest wrapping all the buttons in a View which itself can be centered in the RelativeLayout, such as a TableLayout. Here is a LinearLayout approach since you really only need the button-grid centered in a RelativeLayout. You can get all the buttons to fill the screen (like in the third photo) in a TableLayout using android:stretchColumns="*".
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/textView"
android:background="#fbf8c9"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#fbf8c9"
android:layout_marginTop="10dp"
android:id="#+id/textView2"/>
<RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent">
<TableLayout android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp">
<TableRow>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1"
android:id="#+id/button"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2"
android:id="#+id/button2"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="3"
android:id="#+id/button3"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="*"
android:id="#+id/button13"
android:onClick="buttonOnClick"/>
</TableRow>
<TableRow>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="4"
android:id="#+id/button4"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="5"
android:id="#+id/button5"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="6"
android:id="#+id/button6"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="/"
android:id="#+id/button14"
android:onClick="buttonOnClick"/>
</TableRow>
<TableRow>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="7"
android:id="#+id/button7"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="8"
android:id="#+id/button8"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="9"
android:id="#+id/button9"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="-"
android:id="#+id/button15"
android:onClick="buttonOnClick"/>
</TableRow>
<TableRow>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="AC"
android:id="#+id/button16"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="="
android:id="#+id/button12"
android:onClick="buttonOnClick"
android:background="#dcfa82"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:id="#+id/button10"
android:onClick="buttonOnClick"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:id="#+id/button11"
android:onClick="buttonOnClick"/>
</TableRow>
</TableLayout>
</RelativeLayout>
</LinearLayout>

How about this?
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:background="#fbf8c9"
android:editable="true"
android:text="123243"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_marginTop="10dp"/>
<RelativeLayout
android:id="#+id/relLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_marginTop="100dp">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toLefttOf="#+id/button2"
android:onClick="buttonOnClick"
android:text="1" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button5"
android:layout_toEndOf="#+id/button"
android:layout_toRightOf="#+id/button"
android:onClick="buttonOnClick"
android:text="2" />
<Button
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button2"
android:layout_toEndOf="#+id/button2"
android:layout_toRightOf="#+id/button2"
android:onClick="buttonOnClick"
android:text="3" />
<Button
android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button"
android:layout_alignStart="#+id/button"
android:layout_below="#+id/button"
android:onClick="buttonOnClick"
android:text="4" />
<Button
android:id="#+id/button5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button8"
android:layout_toLeftOf="#+id/button3"
android:layout_toStartOf="#+id/button3"
android:onClick="buttonOnClick"
android:text="5" />
<Button
android:id="#+id/button6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/button3"
android:layout_toEndOf="#+id/button2"
android:layout_toRightOf="#+id/button2"
android:onClick="buttonOnClick"
android:text="6" />
<Button
android:id="#+id/button7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button4"
android:layout_alignStart="#+id/button4"
android:layout_below="#+id/button4"
android:onClick="buttonOnClick"
android:text="7" />
<Button
android:id="#+id/button8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/button4"
android:layout_toLeftOf="#+id/button6"
android:layout_toStartOf="#+id/button6"
android:onClick="buttonOnClick"
android:text="8" />
<Button
android:id="#+id/button9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button8"
android:layout_toEndOf="#+id/button8"
android:layout_toRightOf="#+id/button8"
android:onClick="buttonOnClick"
android:text="9" />
<Button
android:id="#+id/button10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button12"
android:layout_toLeftOf="#+id/button12"
android:layout_toStartOf="#+id/button12"
android:onClick="buttonOnClick"
android:text="0" />
<Button
android:id="#+id/button11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button12"
android:layout_toEndOf="#+id/button12"
android:layout_toRightOf="#+id/button12"
android:onClick="buttonOnClick"
android:text="+" />
<Button
android:id="#+id/button12"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignEnd="#+id/button9"
android:layout_alignRight="#+id/button9"
android:layout_below="#+id/button8"
android:background="#dcfa82"
android:onClick="buttonOnClick"
android:text="=" />
<Button
android:id="#+id/button13"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button3"
android:layout_toRightOf="#+id/button3"
android:onClick="buttonOnClick"
android:text="*" />
<Button
android:id="#+id/button14"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button6"
android:layout_below="#+id/button3"
android:layout_toRightOf="#+id/button6"
android:onClick="buttonOnClick"
android:text="/" />
<Button
android:id="#+id/button15"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button9"
android:layout_toRightOf="#+id/button9"
android:onClick="buttonOnClick"
android:text="-" />
<Button
android:id="#+id/button16"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignTop="#+id/button10"
android:onClick="buttonOnClick"
android:text="AC" />
</RelativeLayout>
<TextView
android:id="#+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="50dp"
android:background="#fbf8c9"
android:editable="true"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
Portrait:
Landscape:

Below code should work, but I don't suggest using RelativeLayout which causes slow performance compared to other ViewGroups. Also you should reference existing calculator apps and separate portrait and landscape into 2 different layouts.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true" >
<TextView
android:id="#+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="10dp"
android:background="#fbf8c9"
android:editable="true"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="#+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="#+id/textView2"
android:layout_marginTop="10dp"
android:background="#fbf8c9"
android:editable="true"
android:textAppearance="?android:attr/textAppearanceLarge" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView1"
android:layout_marginTop="10dp"
android:layout_centerHorizontal="true">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toLefttOf="#+id/button2"
android:onClick="buttonOnClick"
android:text="1" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button5"
android:layout_toEndOf="#+id/button"
android:layout_toRightOf="#+id/button"
android:onClick="buttonOnClick"
android:text="2" />
<Button
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button2"
android:layout_toEndOf="#+id/button2"
android:layout_toRightOf="#+id/button2"
android:onClick="buttonOnClick"
android:text="3" />
<Button
android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button"
android:layout_alignStart="#+id/button"
android:layout_below="#+id/button"
android:onClick="buttonOnClick"
android:text="4" />
<Button
android:id="#+id/button5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button8"
android:layout_toLeftOf="#+id/button3"
android:layout_toStartOf="#+id/button3"
android:onClick="buttonOnClick"
android:text="5" />
<Button
android:id="#+id/button6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/button3"
android:layout_toEndOf="#+id/button2"
android:layout_toRightOf="#+id/button2"
android:onClick="buttonOnClick"
android:text="6" />
<Button
android:id="#+id/button7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button4"
android:layout_alignStart="#+id/button4"
android:layout_below="#+id/button4"
android:onClick="buttonOnClick"
android:text="7" />
<Button
android:id="#+id/button8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/button4"
android:layout_toLeftOf="#+id/button6"
android:layout_toStartOf="#+id/button6"
android:onClick="buttonOnClick"
android:text="8" />
<Button
android:id="#+id/button9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button8"
android:layout_toEndOf="#+id/button8"
android:layout_toRightOf="#+id/button8"
android:onClick="buttonOnClick"
android:text="9" />
<Button
android:id="#+id/button10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button12"
android:layout_toLeftOf="#+id/button12"
android:layout_toStartOf="#+id/button12"
android:onClick="buttonOnClick"
android:text="0" />
<Button
android:id="#+id/button11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button12"
android:layout_toEndOf="#+id/button12"
android:layout_toRightOf="#+id/button12"
android:onClick="buttonOnClick"
android:text="+" />
<Button
android:id="#+id/button12"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignEnd="#+id/button9"
android:layout_alignRight="#+id/button9"
android:layout_below="#+id/button8"
android:background="#dcfa82"
android:onClick="buttonOnClick"
android:text="=" />
<Button
android:id="#+id/button13"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button3"
android:layout_toRightOf="#+id/button3"
android:onClick="buttonOnClick"
android:text="*" />
<Button
android:id="#+id/button14"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button6"
android:layout_below="#+id/button3"
android:layout_toRightOf="#+id/button6"
android:onClick="buttonOnClick"
android:text="/" />
<Button
android:id="#+id/button15"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/button9"
android:layout_toRightOf="#+id/button9"
android:onClick="buttonOnClick"
android:text="-" />
<Button
android:id="#+id/button16"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignTop="#+id/button10"
android:onClick="buttonOnClick"
android:text="AC" />
</RelativeLayout>
</RelativeLayout>
</RelativeLayout>

My android layout changes each time i chose a different device in emulator even if they have approximately same size?

Here is my xml file
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingLeft="15dp"
android:paddingRight="15dp"
tools:context=".MainActivity" >
<TextView
android:id="#+id/ResultText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="right"
android:textSize="20sp"
android:layout_marginTop="5dp"
android:background="#EEEEEE" />
<TextView
android:id="#+id/InputText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/ResultText"
android:layout_below="#+id/ResultText"
android:background="#BBBBBB"
android:gravity="right"
android:textColor="#FFFFFF"
android:layout_marginTop="4dp"
android:textSize="15sp" />
<Button
android:id="#+id/button5"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button1"
android:layout_below="#+id/button1"
android:text="5" />
<Button
android:id="#+id/button7"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button3"
android:layout_alignTop="#+id/button6"
android:text="7" />
<Button
android:id="#+id/button8"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button4"
android:layout_alignTop="#+id/button7"
android:text="8" />
<Button
android:id="#+id/button9"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button5"
android:layout_below="#+id/button5"
android:text="9" />
<Button
android:id="#+id/buttonMultiply"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/buttonDivide"
android:text="x" />
<Button
android:id="#+id/buttonSubtract"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/buttonAdd"
android:layout_alignBottom="#+id/buttonAdd"
android:layout_alignParentRight="true"
android:text="-" />
<Button
android:id="#+id/buttonDivide"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button8"
android:layout_alignBottom="#+id/button8"
android:layout_alignLeft="#+id/buttonAdd"
android:text="/" />
<Button
android:id="#+id/buttonAdd"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button4"
android:layout_alignBottom="#+id/button4"
android:layout_toLeftOf="#+id/buttonSubtract"
android:text="+" />
<Button
android:id="#+id/button4"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button8"
android:layout_toLeftOf="#+id/buttonDivide"
android:text="4" />
<Button
android:id="#+id/button3"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button7"
android:layout_toLeftOf="#+id/button8"
android:text="3" />
<Button
android:id="#+id/buttonDot"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button0"
android:layout_alignBottom="#+id/button0"
android:layout_alignLeft="#+id/button7"
android:text="." />
<Button
android:id="#+id/button2"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button3"
android:layout_alignBottom="#+id/button3"
android:layout_toLeftOf="#+id/button3"
android:text="2" />
<Button
android:id="#+id/button6"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button0"
android:layout_toLeftOf="#+id/button7"
android:text="6" />
<Button
android:id="#+id/button0"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button9"
android:layout_alignBottom="#+id/button9"
android:layout_alignLeft="#+id/button6"
android:text="0" />
<Button
android:id="#+id/button1"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/InputText"
android:layout_marginTop="26dp"
android:layout_toLeftOf="#+id/button2"
android:text="1" />
<Button
android:id="#+id/buttonEqual"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/buttonDot"
android:layout_alignBottom="#+id/buttonDot"
android:layout_alignRight="#+id/buttonMultiply"
android:layout_toRightOf="#+id/button8"
android:text="=" />
<Button
android:id="#+id/buttonDel"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/buttonDot"
android:layout_toRightOf="#+id/buttonDot"
android:text="del" />
<Button
android:id="#+id/buttonSin"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button9"
android:layout_below="#+id/button9"
android:text="sin" />
<Button
android:id="#+id/buttonCos"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button0"
android:layout_alignTop="#+id/buttonSin"
android:text="cos" />
<Button
android:id="#+id/buttonTan"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/buttonDot"
android:layout_alignTop="#+id/buttonCos"
android:text="tan" />
<Button
android:id="#+id/buttonCot"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/buttonSec"
android:text="cot" />
<Button
android:id="#+id/buttonSec"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/buttonCosec"
android:layout_alignBottom="#+id/buttonCosec"
android:layout_toLeftOf="#+id/buttonCot"
android:text="sec" />
<Button
android:id="#+id/buttonCosec"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/buttonTan"
android:layout_alignBottom="#+id/buttonTan"
android:layout_toLeftOf="#+id/buttonSec"
android:layout_marginLeft="1dp"
android:text="csec" />
<Button
android:id="#+id/buttonPow"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/buttonSin"
android:layout_below="#+id/buttonSin"
android:layout_alignRight="#+id/buttonSin"
android:gravity="left"
android:textSize="10sp"
android:text="yX" />
<Button
android:id="#+id/buttonLog10"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/buttonPow"
android:layout_toRightOf="#+id/buttonPow"
android:text="log" />
<Button
android:id="#+id/buttonLoge"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/buttonLog10"
android:layout_alignBottom="#+id/buttonLog10"
android:layout_toRightOf="#+id/buttonLog10"
android:text="ln" />
<Button
android:id="#+id/buttonSquare"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/buttonLoge"
android:layout_toRightOf="#+id/buttonLoge"
android:text="sqr" />
<Button
android:id="#+id/buttonSqrt"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/buttonSquare"
android:layout_toRightOf="#+id/buttonSquare"
android:text="sqrt" />
<Button
android:id="#+id/buttonFactorial"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/buttonSqrt"
android:text="x!" />
<Button
android:id="#+id/buttonSinh"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/buttonPow"
android:layout_below="#+id/buttonPow"
android:layout_toLeftOf="#+id/buttonLoge"
android:text="sinh" />
<Button
android:id="#+id/buttonCosh"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/buttonSinh"
android:layout_alignBottom="#+id/buttonSinh"
android:layout_alignLeft="#+id/buttonLoge"
android:layout_toLeftOf="#+id/buttonSqrt"
android:text="cosh" />
<Button
android:id="#+id/buttonTanh"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/buttonSqrt"
android:layout_alignRight="#+id/buttonFactorial"
android:layout_alignTop="#+id/buttonCosh"
android:text="tanh" />
</RelativeLayout>
here are some screen shots:
As you can see the left portion is not filled completely it is on a 4.65 inch xhdpi screen
On a 4 inch hdpi screen its perfect covering full width and full height

Basically, what Ben Pearson suggested, you can use TableLayout and several TableRow layouts. For example, a single row layout XML might look like this:
<TableRow
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:id="#+id/button5"
style="?android:attr/buttonStyleSmall"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="5" />
<Button
android:id="#+id/button6"
style="?android:attr/buttonStyleSmall"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="6" />
<Button
android:id="#+id/button7"
style="?android:attr/buttonStyleSmall"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="7" />
<Button
android:id="#+id/button8"
style="?android:attr/buttonStyleSmall"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="8" />
<Button
android:id="#+id/buttonDivide"
style="?android:attr/buttonStyleSmall"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="/" />
<Button
android:id="#+id/buttonMultiply"
style="?android:attr/buttonStyleSmall"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="x" />
</TableRow>
Note that since TableRow is a subclass of LinearLayout, it understands the layout_weight attribute on its children. Set the layout_width to 0dp and layout_weight to 1 on each button (or 2, for some buttons).

ScrollView won't scroll

I am new to Android Programming(started yesterday, infact) and I cannot, for the life of me, get ScrollView to scroll. I have a bunch of buttons which won't all fit on the screen, so I tried to add a scroll function. However, this doesn't work. I am running an emulator if that helps. Here is my XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".UnleashedMainPageActivity" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/unleashed_Main" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_below="#+id/textView1"
android:text="#string/choose_Mod" />
<Button
android:id="#+id/button4"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView2"
android:layout_alignRight="#+id/textView2"
android:layout_below="#+id/textView2"
android:text="Applied Energistics" />
<Button
android:id="#+id/button1"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button4"
android:layout_alignRight="#+id/button4"
android:layout_below="#+id/button4"
android:text="Buildcraft" />
<Button
android:id="#+id/button2"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button1"
android:layout_alignRight="#+id/button1"
android:layout_below="#+id/button1"
android:text="Computer Craft" />
<Button
android:id="#+id/button3"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button2"
android:layout_alignRight="#+id/button2"
android:layout_below="#+id/button2"
android:text="Ender Storage" />
<Button
android:id="#+id/button5"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button3"
android:layout_alignRight="#+id/button3"
android:layout_below="#+id/button3"
android:text="Equivalent Exchange 3" />
<Button
android:id="#+id/button6"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button5"
android:layout_alignRight="#+id/button5"
android:layout_below="#+id/button5"
android:text="ExtraBiomes/Biomes O' Plenty" />
<Button
android:id="#+id/button7"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button6"
android:layout_alignRight="#+id/button6"
android:layout_below="#+id/button6"
android:text="Factorization" />
<Button
android:id="#+id/button8"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button7"
android:layout_alignRight="#+id/button7"
android:layout_below="#+id/button7"
android:text="Forestry" />
<Button
android:id="#+id/button9"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button8"
android:layout_alignRight="#+id/button8"
android:layout_below="#+id/button8"
android:text="IndustrialCraft 2" />
<Button
android:id="#+id/button10"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button9"
android:layout_alignRight="#+id/button9"
android:layout_below="#+id/button9"
android:text="MineFactory Reloaded" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button10"
android:layout_alignLeft="#+id/button4"
android:layout_alignTop="#+id/button4"
android:orientation="vertical" >
<ScrollView
android:id="#+id/scrollView1"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
</LinearLayout>
</ScrollView>
</LinearLayout>
</RelativeLayout>

replace :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".UnleashedMainPageActivity" >
<ScrollView
android:id="#+id/scrollView1"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/unleashed_Main" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_below="#+id/textView1"
android:text="#string/choose_Mod" />
<Button
android:id="#+id/button4"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView2"
android:layout_alignRight="#+id/textView2"
android:layout_below="#+id/textView2"
android:text="Applied Energistics" />
<Button
android:id="#+id/button1"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button4"
android:layout_alignRight="#+id/button4"
android:layout_below="#+id/button4"
android:text="Buildcraft" />
<Button
android:id="#+id/button2"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button1"
android:layout_alignRight="#+id/button1"
android:layout_below="#+id/button1"
android:text="Computer Craft" />
<Button
android:id="#+id/button3"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button2"
android:layout_alignRight="#+id/button2"
android:layout_below="#+id/button2"
android:text="Ender Storage" />
<Button
android:id="#+id/button5"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button3"
android:layout_alignRight="#+id/button3"
android:layout_below="#+id/button3"
android:text="Equivalent Exchange 3" />
<Button
android:id="#+id/button6"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button5"
android:layout_alignRight="#+id/button5"
android:layout_below="#+id/button5"
android:text="ExtraBiomes/Biomes O' Plenty" />
<Button
android:id="#+id/button7"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button6"
android:layout_alignRight="#+id/button6"
android:layout_below="#+id/button6"
android:text="Factorization" />
<Button
android:id="#+id/button8"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button7"
android:layout_alignRight="#+id/button7"
android:layout_below="#+id/button7"
android:text="Forestry" />
<Button
android:id="#+id/button9"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button8"
android:layout_alignRight="#+id/button8"
android:layout_below="#+id/button8"
android:text="IndustrialCraft 2" />
<Button
android:id="#+id/button10"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button9"
android:layout_alignRight="#+id/button9"
android:layout_below="#+id/button9"
android:text="MineFactory Reloaded" />
</LinearLayout>
</ScrollView>
</RelativeLayout>

at first you don't have close tag for RelativeLayout.
and if you want scrollview work then you have to insert enough views in scrollview for fill screen height

buttons aligment in virtual device

I am trying to align buttons like simple calculator
But when i align buttons like that when i run it buttons can shift from desired location.
I can't understand what is problem.
here is code :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/activity_horizontal_margin"
android:gravity="fill_vertical"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="#+id/button11"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button4"
android:layout_alignBottom="#+id/button4"
android:layout_alignLeft="#+id/button14"
android:layout_toLeftOf="#+id/button12"
android:onClick="#string/_onclick"
android:text="#string/_4" />
<Button
android:id="#+id/button16"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button4"
android:layout_toLeftOf="#+id/button5"
android:onClick="#string/_onclick"
android:text="#string/_9" />
<Button
android:id="#+id/button7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button6"
android:layout_alignParentBottom="true"
android:layout_marginBottom="16dp"
android:onClick="#string/_onclick"
android:text="#string/_" />
<Button
android:id="#+id/button8"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#id/button7"
android:layout_alignLeft="#+id/button11"
android:layout_toLeftOf="#+id/button9"
android:onClick="#string/_onclick"
android:text="#string/_1" />
<Button
android:id="#+id/button10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button7"
android:layout_toRightOf="#+id/button1"
android:onClick="#string/_onclick"
android:text="#string/_3" />
<Button
android:id="#+id/button6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button7"
android:layout_alignLeft="#+id/button4"
android:onClick="#string/_onclick"
android:text="#string/_jam" />
<Button
android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button12"
android:layout_alignBottom="#+id/button12"
android:layout_alignLeft="#+id/button5"
android:onClick="#string/_onclick"
android:text="#string/_menha" />
<Button
android:id="#+id/button5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button16"
android:layout_alignBottom="#+id/button16"
android:layout_alignLeft="#+id/button3"
android:onClick="#string/_onclick"
android:text="#string/_zarb" />
<Button
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button5"
android:layout_alignParentRight="true"
android:layout_marginRight="15dp"
android:onClick="#string/_onclick"
android:text="#string/_taghsim" />
<Button
android:id="#+id/button14"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/button11"
android:layout_toLeftOf="#+id/button12"
android:onClick="#string/_onclick"
android:text="#string/_7" />
<Button
android:id="#+id/button15"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/button13"
android:layout_alignLeft="#+id/button12"
android:layout_toLeftOf="#+id/button13"
android:onClick="#string/_onclick"
android:text="#string/_8" />
<Button
android:id="#+id/button9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button7"
android:layout_alignLeft="#id/button12"
android:layout_alignTop="#id/button10"
android:layout_toLeftOf="#+id/button10"
android:onClick="#string/_onclick"
android:text="#string/_2" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button3"
android:layout_alignBottom="#+id/button3"
android:layout_toLeftOf="#+id/button3"
android:layout_toRightOf="#+id/button1"
android:onClick="#string/_onclick"
android:text="#string/c" />
<Button
android:id="#+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/button14"
android:layout_alignLeft="#+id/button14"
android:layout_alignParentBottom="false"
android:layout_alignParentRight="false"
android:layout_alignRight="#+id/button15"
android:layout_alignWithParentIfMissing="false"
android:layout_centerInParent="false"
android:onClick="#string/_onclick"
android:text="#string/ce" />
<Button
android:id="#+id/button17"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button7"
android:layout_alignBottom="#+id/button7"
android:layout_alignRight="#+id/button10"
android:layout_toRightOf="#+id/button9"
android:onClick="#string/_onclick"
android:text="#string/_dot" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button1"
android:layout_alignParentTop="true"
android:layout_marginLeft="17dp"
android:layout_marginTop="59dp"
android:textSize="20sp"
tools:ignore="SpUsage" />
<Button
android:id="#+id/button13"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#id/button10"
android:layout_alignBaseline="#+id/button12"
android:layout_alignBottom="#+id/button12"
android:layout_alignLeft="#+id/button16"
android:layout_below="#id/button16"
android:layout_toLeftOf="#id/button4"
android:onClick="#string/_onclick"
android:text="#string/_6" />
<Button
android:id="#+id/Button01"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/button8"
android:layout_toLeftOf="#+id/button17"
android:onClick="#string/_onclick"
android:text="#string/_0" />
<Button
android:id="#+id/button12"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/button10"
android:layout_toLeftOf="#+id/button13"
android:onClick="#string/_onclick"
android:text="#string/_5" />
this is screenshot of my problems:
http://i39.tinypic.com/xm04lz.jpg
http://i42.tinypic.com/ibgmk3.jpg
please help me how can i solve the problem

Why are you making your life so difficult? Stop this alignment madness and use LinearLayouts. Create a LinearLayout and put the 5 rows of buttons inside, with each row as LinearLayout. Then use the layout_weight parameter to add them the same (or desired) width.
Example:
<LinearLayout>
<LinearLayout>
Button Button Button Button
</LinearLayout>
<LinearLayout>
Button Button Button Button
</LinearLayout>
....
</LinearLayout>

Named Buttons in Android

I am trying to create a button in an Android layout with name "=" and Eclipse says:
It is not acceptable.
How can I create a button with name "=" or "1" etc?
here is the buttons:
Here is xml code
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<Button
android:id="#+id/button1"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_marginLeft="29dp"
android:layout_marginTop="98dp"
android:text="7" />
<Button
android:id="#+id/button2"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button1"
android:layout_toRightOf="#+id/button1"
android:text="8" />
<Button
android:id="#+id/button3"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button2"
android:layout_toRightOf="#+id/button2"
android:text="9" />
<Button
android:id="#+id/button4"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button1"
android:layout_below="#+id/button1"
android:text="4" />
<Button
android:id="#+id/button5"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button4"
android:layout_alignLeft="#+id/button2"
android:text="5" />
<Button
android:id="#+id/button6"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button5"
android:layout_toRightOf="#+id/button2"
android:text="6" />
<Button
android:id="#+id/button7"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button4"
android:layout_below="#+id/button4"
android:text="1" />
<Button
android:id="#+id/button8"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button7"
android:layout_toRightOf="#+id/button4"
android:text="2" />
<Button
android:id="#+id/button9"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button8"
android:layout_toRightOf="#+id/button5"
android:text="3" />
<Button
android:id="#+id/button10"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button7"
android:layout_below="#+id/button7"
android:text="." />
<Button
android:id="#+id/button11"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/button10"
android:layout_toRightOf="#+id/button7"
android:text="0" />
<Button
android:id="#+id/button12"
style="?android:attr/buttonStyleSmall"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button11"
android:layout_alignBottom="#+id/button11"
android:layout_alignLeft="#+id/button9"
android:text="=" />
<Button
android:id="#+id/button13"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_above="#+id/button6"
android:layout_toRightOf="#+id/button3"
android:text="/" />
<Button
android:id="#+id/button14"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button6"
android:layout_alignBottom="#+id/button6"
android:layout_alignRight="#+id/button13"
android:layout_toRightOf="#+id/button3"
android:freezesText="true"
android:text="-" />
<Button
android:id="#+id/button15"
style="?android:attr/buttonStyleSmall"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/button9"
android:layout_alignBottom="#+id/button9"
android:layout_toRightOf="#+id/button6"
android:text="+" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/button1"
android:layout_alignParentTop="true"
android:layout_marginTop="70dp"
android:text="#string/hello_world"
tools:context=".MainActivity" />
</RelativeLayout>

You are confusing the name of the button with the text shown on the button. So please give your button the name "buttonEquals" (or the like), and just set its text (or label) to "=".

Button mybtn = (Button)findViewById(R.id.YOURBUTTONID);
mybtn.setText("=");