android *** Layout 02

相对布局

主要是这个

android:layout_alignParentTop

If "true", makes the top edge of this view match the top edge of the parent.

android:layout_centerVertical

If "true", centers this child vertically within its parent.

android:layout_below

Positions the top edge of this view below the view specified with a resource ID.

android:layout_toRightOf

Positions the left edge of this view to the right of the view specified with a resource ID.

来源于http://android-doc.com/guide/topics/ui/layout/relative.html

相应的xml是

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="41dp"
        android:layout_marginTop="28dp"
        android:textSize="30sp"
        android:text="用户名："
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <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="密码："
        android:textSize="30sp"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/textView1"
        android:layout_toRightOf="@+id/textView1"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/editText2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/textView2"
        android:layout_alignBottom="@+id/textView2"
        android:layout_toRightOf="@+id/textView1"
        android:ems="10"
        android:inputType="textPassword" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/editText2"
        android:layout_marginLeft="21dp"
        android:layout_marginTop="75dp"
        android:text="登陆" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button1"
        android:layout_alignLeft="@+id/editText2"
        android:layout_marginLeft="33dp"
        android:text="取消" />

</RelativeLayout>