[Android]Android布局优化之 ViewStub

转载请标注：转载于http://www.cnblogs.com/Liuyt-61/p/6602926.html

----------------------------------------------------------------

>使用ViewStub惰性加载

作用：ViewStub标签同include标签一样可以用来引入一个外部布局，不同的是，ViewStub引入的布局默认不会扩张，既不会占用显示，也不会占用位置，从而在解析layout时节省cpu和内存。

common_text.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" >

    <TextView

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="隐藏内容" />

</LinearLayout>

------------------------------------------------

main.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" >

    <include layout="@layout/common_title" />

    <FrameLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

        <TextView

            android:id="@+id/textView"

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:text="正文内容"

            android:textSize="16sp" />

        <include layout="@layout/common_progress" />

    </FrameLayout>

    <Button

        android:id="@+id/button"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="显示隐藏内容" />

    <ViewStub

        android:id="@+id/viewStub"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout="@layout/common_text" />

</LinearLayout>

--------------------------------------

MainActivity.java

package com.Liuyt.s03_e22_include;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.ViewStub;

import android.widget.Button;

public class MainActivity extends Activity {

    private Button btn;

    private ViewStub viewStub;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        btn = (Button) findViewById(R.id.button);

        viewStub = (ViewStub) findViewById(R.id.viewStub);

        btn.setOnClickListener(new OnClickListener() {

            @Override

            public void onClick(View arg0) {

                // TODO Auto-generated method stub

                viewStub.inflate();

            }

        });

    }

}