What does FrameLayout do?

问题:

I'm new to programming. I was using Graphical Layout then when I was reading xml file, I saw FrameLayout. Then I searched, but I couldn't find something useful. What is FrameLayout and what does it do?

回答1:

You use a FrameLayout to stack child views on top of each other, with the most recent child on top of the stack. In the example below, the TextView is the most recent, so it is automatically placed on top of the ImageView.

For example:

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

    <ImageView
        android:id="@+id/backgroundImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="centerCrop"
        android:src="@drawable/bitmapie" />

    <TextView
        android:id="@+id/descTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginTop="70dp"
        android:background="@android:color/holo_blue_light"
        android:padding="10dp"
        android:text="TextView placed at the top of the Imageview"
        android:textColor="@android:color/white"
        android:textSize="22sp" />

</FrameLayout>

Output:

回答2:

Are you sure that you googled it?

• http://www.tutorialspoint.com/android/android_frame_layout.htm

Frame Layout is designed to block out an area on the screen to display a single item. Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organize child views in a way that's scalable to different screen sizes without the children overlapping each other.

You can, however, add multiple children to a FrameLayout and control their position within the FrameLayout by assigning gravity to each child, using the android:layout_gravity attribute.

• http://blog.neteril.org/blog/2013/10/10/framelayout-your-best-ui-friend/

The secret of FrameLayout is how it layouts its children. Although normally designed to contain one item, it will happily stack up other element on top of each other. Thus FrameLayout is essentially a way to manipulate the Z-order of views on the screen.

This is super useful for a couple of UI tricks from HUD-like elements to sliding panels to more complex animated transitions. In this post we will see an example for each of those.

• http://www.learn-android-easily.com/2013/05/frame-layout-in-androis.html

FrameLayout is designed to display a single item at a time. You can have multiple elements within a FrameLayout but each element will be positioned based on the top left of the screen. Elements that overlap will be displayed overlapping. I have created a simple XML layout using FrameLayout that shows how this works.

回答3:

You can consider the word frame as regular photo frame. What you do with that frame? you can place photos in that frame by one top to another. Same as in FrameLayout we can place views ( Any layout, or widget like button, text, image so on) top of other as @ojonugwa shows you the textview top of the Image.

回答4:

FrameLayout is designed to block out an area on the screen to display a single item. Generally, FrameLayout should be used to hold a single child view, because it can be difficult to organize child views in a way that’s scalable to different screen sizes without the children overlapping each other. You can, however, add multiple children to a FrameLayout and control their position within the FrameLayout by assigning gravity to each child, using the android:layout_gravity attribute.

Child views are drawn in a stack, with the most recently added child on top.

The source are here - https://medium.com/@anamikatripathi1601/android-beginners-views-layouts-657a5bbeebe2

Another popular approach of using FrameLayout it is Fragment container

回答5:

Basically it puts one view on top of another for example :

Inflating text on Image

  <FrameLayout>

<ImageView>
<Textview>

  </FrameLayout>