Android layout include, merge, Viewstub

In the layout optimization, Androi's official mentions these three kinds of layout <include/>, <merge/>, <viewstub/>, and describes the advantages of each of the three layouts, the following is a brief talk about their advantages, and how to use , simply review.

1. Layout Reuse <include/>

<include/> Tags can reuse layout files, simple to use as follows:

<span style= "FONT-SIZE:12PX;" ><linearlayout xmlns:android= "http://schemas.android.com/apk/res/android"      android:orientation= " Vertical "       android:layout_width=" match_parent "      android:layout_height=" Match_parent "      android: background= "@color/app_bg"      android:gravity= "Center_horizontal" >        <include layout= "@layout/titlebar "/> ...  </LinearLayout> </span>

Description: 1) The <include/> Tag can use a separate layout property, which is also required.

    2) can use other properties. <include/> id Span style= "padding:0px; margin:0px; Line-height:28px "" And your layout id your layout id will be overwritten with the solution.

    3) in include label all android:layout_* layout_width and layout_height two properties

4) A layout can contain two identical include tags.

2. Reduce the view level <merge/>

    <merge/> tags play a very important role in the structural optimization of the UI, which can be used to prune unnecessary layers and optimize the UI. <merge/> more for replacing Framelay out or When one layout contains another, <MERGE/> Slow down your UI performance. You can use the <merge/> label optimization.

<span style= "FONT-SIZE:12PX;" ><merge xmlns:android= "Http://schemas.android.com/apk/res/android" >      <button          android:layout_ Width= "Fill_parent"           android:layout_height= "wrap_content"          android:text= "@string/add"/>      < Button          android:layout_width= "fill_parent"           android:layout_height= "wrap_content"          android:text= "@ String/delete "/>  </merge> </span>

more <merge/> Introduction can refer to click to open the link
3. Use <viewstub/> when needed

The biggest advantage of the <viewstub/> tag is that it does not load when you need it, and it doesn't affect performance when the UI is initialized. A variety of infrequently used layouts like progress bars, display error messages, and so on can use <viewstub/> tags to reduce memory usage and speed rendering. <viewstub/> is an invisible, 0 - size View. <viewstub/> Tags are used as follows:

<span style= "FONT-SIZE:12PX;" ><viewstub      android:id= "@+id/stub_import"      android:inflatedid= "@+id/panel_import"      android: layout= "@layout/progress_overlay"      android:layout_width= "fill_parent"      android:layout_height= "Wrap_ Content "      android:layout_gravity=" bottom "/> </span>

Description

when callingInflate ()function,viewstubThe referenced resource is substituted and returns the referencedView.  This program can be directly referenced by theViewWithout having to call the function againFindviewbyid ()

viewstub now, there's a flaw that doesn't support it . <merge/> tags.
More <viewstub/> Label Introduction can be consulted: Click to open the link

Android layout include, merge, Viewstub