activity.xml

<?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"
    android:background="#ffffff"
    >
    
    <LinearLayout
       android:orientation="horizontal"     
       android:layout_width="fill_parent"    
       android:layout_height="27dp"   
       android:layout_marginTop="5px"
       android:layout_marginLeft="0px"
       android:layout_marginRight="0px"
       android:layout_weight="0.02">
        
        <Button
            android:layout_width="wrap_content"
            android:layout_height="fill_parent"
            android:text="PRE"
            android:id="@+id/pre"
            android:layout_weight="0.16"
                />
        
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="fill_parent"
            android:id="@+id/tv_dater"
            android:background="#11ff00"
            android:textColor="#ffffff"
            android:layout_weight="3"
            android:textSize="31.5sp"
            android:gravity="center_horizontal|center_vertical"
                  />
        
        <Button
            android:layout_width="wrap_content"
            android:layout_height="fill_parent"
            android:text="NEXT"
            android:id="@+id/next"
            android:layout_weight="0.16"

                />
                  
    </LinearLayout>
    
    <TextView 
        android:id="@+id/tv_date"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="#ff00000"
        android:gravity="center_vertical"
        android:paddingLeft="10dp"
        android:textColor="#ffffff"
        android:textSize="20sp"
        android.layout_weight="0.01"
        />
    
    <GridView
              
        android:layout_marginTop = "10dp"
        android:id = "@+id/gridview"
        android:layout_weight="1"
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:numColumns="7"
        android:listSelector="#b9ff01"
        >
    </GridView>
        
        
</LinearLayout>