布局优化具体流程

1、Include

将 其他的xml文件包含的当前xml文件中来

common_nav.xml

activity_main.xml

2、merge

目的是通过删减多余或者额外的层级，从而优化整个Android Layout的结构。核心功能就是减少冗余的层次从而达到优化UI的目的！—转载

3、ViewStub

延时加载view

package com.example.administrator.layoutoptimize;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewStub;
import android.widget.Button;


public class MainActivity extends ActionBarActivity {
    private boolean inflated = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn = (Button)findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ViewStub viewStub = (ViewStub)findViewById(R.id.viewStub);
                if(!inflated){
                    inflated = true;
                    viewStub.inflate();
                }
            }
        });
    }
}