//file NoteListActivity
package jp.co.ricoh.melody.views.activities;

import android.databinding.DataBindingUtil;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;

import junit.framework.Test;

import jp.co.ricoh.melody.R;
import jp.co.ricoh.melody.databinding.NoteListActivityBinding;
import jp.co.ricoh.melody.presenters.INoteListActivityPresenter;
import jp.co.ricoh.melody.presenters.NoteActivityPresenter;
import jp.co.ricoh.melody.presenters.NoteListActivityPresenter;
import jp.co.ricoh.melody.views.fragments.NoteListFragment;

import static android.R.attr.fragment;

/**
 * Created by leonard on 17-3-11.
 */
public class NoteListActivity extends BaseActivity implements NoteActivityPresenter {

    private NoteListActivityBinding mViewDataBinding;
    private INoteListActivityPresenter mActivityPresenter;
    private Fragment mCurrentFragment;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initView(savedInstanceState);
    }

   /* this contain all note functions.
   * content layout contain note list layout,note item layout,layout item edit
   * back key will change in fragemnt backstack
   * */

    private void initView(Bundle savedInstanceState) {
        mViewDataBinding = DataBindingUtil.setContentView(this, R.layout.activity_note);
        mActivityPresenter = NoteListActivityPresenter.newInstance();
        if (savedInstanceState==null) {
            Fragment fragment = NoteListFragment.newInstance();
            switchContent(fragment,true);
        }
    }
    @Override
    public void switchContent(Fragment newFragemnt, boolean reuse) {
        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction().setCustomAnimations(
                android.R.anim.fade_in, android.R.anim.fade_out);
        if (reuse){
            newFragemnt = getSupportFragmentManager().findFragmentByTag(newFragemnt.getTag());
        }
        if (!newFragemnt.isAdded()) {    // 先判断是否被add过
            transaction.hide(mCurrentFragment).add(R.id.contentFrame, newFragemnt).commitAllowingStateLoss(); // 隐藏当前的fragment，add下一个到Activity中
        } else {
            transaction.hide(mCurrentFragment).show(newFragemnt).commitAllowingStateLoss(); // 隐藏当前的fragment，显示下一个
        }
        mCurrentFragment = newFragemnt;
    }

    @Override
    public void setTitle(String title) {
        mViewDataBinding.toolbar.setTitle(R.string.app_name);
    }
}

//file NoteActivityPresenter

package jp.co.ricoh.melody.presenters;

import android.support.v4.app.Fragment;

/**
 * Created by leonard on 17-3-13.
 */
public interface NoteActivityPresenter {
    void switchContent(Fragment newFragemnt, boolean reuse);
    void setTitle(String title);
}

//res activity_note
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <data class="NoteListActivityBinding"/>

    <android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
     <include layout="@layout/content_main"
         android:id="@+id/content"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            android:layout_width="match_parent"/>


        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:fitsSystemWindows="true"
            android:layout_height="?attr/actionBarSize">
            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"></android.support.v7.widget.Toolbar>
        </android.support.design.widget.AppBarLayout>

    </android.support.design.widget.CoordinatorLayout>
</layout>

//res content_main
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2016 RICOH Co.,LTD. -->
<!-- All rights reserved. -->
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <FrameLayout
        android:id="@+id/contentFrame"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    </FrameLayout>


</RelativeLayout>