Difficulty with ScrollView and LinearLayout

问题:

I'm trying to make an Android layout: 3 components inside a vertical LinearLayout. The center component is a ScrollView that contains a TextView. When the TextView contains a significant amount of text (more than can fit on the screen), the ScrollView grows all the way to the bottom of the screen, shows scrollbars, and pushes the last component, a LinearLayout with a Button inside, off the screen.

If the text inside the TextView inside the ScrollView is short enough, the button at the bottom of the screen is positioned perfectly.

The layout I'm trying to achieve is:

The XML for the layout I've written is:

<?xml version="1.0" encoding="UTF-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">

    <TextView android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#FFFFFF"
            android:layout_marginLeft="10dip"
            android:layout_marginRight="10dip"
            android:layout_marginTop="10dip"
            android:layout_marginBottom="10dip"
            android:text="Title />

    <ScrollView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">

        <TextView android:id="@+id/text"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:autoLink="web"
                android:textColor="#FFFFFF"
                android:background="#444444"
                android:padding="10dip" />

    </ScrollView>

    <LinearLayout
            android:orientation="horizontal"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:layout_weight="1">

        <LinearLayout
                android:orientation="horizontal"
                android:layout_width="0dip"
                android:layout_height="wrap_content"
                android:layout_weight="1"/>

        <Button android:id="@+id/login_button"
                android:layout_width="0dip"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom"
                android:layout_weight="1"
                android:text="@string/next_button"/>

    </LinearLayout>

</LinearLayout>

回答1:

The scrollview is the second view object and is set to wrap_content, which is more than the screen.

I recommend a RelativeLayout. Top textview first with android:alignParentTop="true", the bottom LinearLayout next with android:alignParentBottom="true" and the scrollview listed last in the xml with the value android:alignBelow="@id/whatYouCallTheHeader.

This will align the bottom bar at the bottom of the screen, and the header at the top, no matter the size. Then the scrollview will have its own place, after the header and footer have been placed.

回答2:

you should go for relativeLayout rather than LinearLayout. And you can use some properties like alignBelow and all.

回答3:

Try adding a layout weight into the ScrollView ie.

<ScrollView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1">

This worked for me in a situation almost identical to the one you're presenting but left me wondering why, because it is counter-intuitive that increasing the layout weight of a control from 0 (the default if you don't specify a layout_weight) to 1 should make a control which is already using too much space smaller.

I suspect the reason it works is that by not specifying a layout_weight you actually allow the layout to ignore the size of the scroll view relative to other controls and conversely if do specify one you give it permission to shrink it in proportion to the weights you assign.

回答4:

![Fixed Header-Footer and scrollable Body layout ][1]

---

This is what you are looking for . Most of the app in android had this type of layout , a fixed header and footer and a scrollable body . The xml for this layout is

---

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
        android:background="#5599DD"
        android:layout_height="fill_parent">
        <!-- Header goes here -->
       <TextView 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#FFFFFF"
            android:layout_marginLeft="10dip"
            android:layout_marginRight="10dip"
            android:layout_marginTop="10dip"
            android:layout_marginBottom="10dip"
            android:textSize="20sp"
            android:layout_gravity="center"
            android:text="Title" />
       <!-- Body goes here -->
        <ScrollView
            android:layout_weight="1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">
            <TextView 
                android:id="@+id/text"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:autoLink="web"
                android:text="@string/lorem_ipsum"
                android:textColor="#FFFFFF"

                android:padding="10dip" />
        </ScrollView>
        <!-- footer goes here -->
        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">
            <RelativeLayout
                android:layout_width="fill_parent"
                android:layout_height="fill_parent">
                <Button 
                    android:id="@+id/login_button"
                    android:layout_height="wrap_content"
                    android:layout_width="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_alignParentRight="true"
                    android:text="Button"/>

            </RelativeLayout>
     </LinearLayout>
</LinearLayout>