利用Fragment实现应用的主布局

Fragment与Viewpager其实都可以实现主界面的布局，但是推荐使用Fragment，因为Fragment对于后期的维护和管理比较有利；

Fragment其实和Viewpager实现的步骤是差不多的，首先看下Fragment的结构图

4个Fragment分开管理各个对应的布局文件

   布局文件用FrameLayout引入Fragment布局

接下来就是activity文件了，代码中有备注也就不多说什么了，这个和Viewpager实现其实大同小异

package com.yongninggo.wechat;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.yongninggo.wechat.Fragment.Home_fragment;
import com.yongninggo.wechat.Fragment.Message_fragment;
import com.yongninggo.wechat.Fragment.Person_fragment;
import com.yongninggo.wechat.Fragment.Pond_fragment;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    //定义所有的控件
    private LinearLayout home_layout_view;
    private LinearLayout message_layout_view;
    private LinearLayout pond_layout_view;
    private LinearLayout person_layout_view;
    private ImageView home_image_view;
    private ImageView message_image_view;
    private ImageView pond_image_view;
    private ImageView person_image_view;
    //定义4个Fragment布局
    private Fragment home;
    private Fragment message;
    private Fragment pond;
    private Fragment person;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        inisview();
        inisEvent();
        setSelect(0);  //设置首次启动应用显示的Fragment界面
    }

    //给4个LinearLayout添加点击事件
    private void inisEvent() {
        home_layout_view.setOnClickListener(this);
        message_layout_view.setOnClickListener(this);
        pond_layout_view.setOnClickListener(this);
        person_layout_view.setOnClickListener(this);
    }

    //初始化所有控件
    private void inisview() {
        home_layout_view = (LinearLayout) findViewById(R.id.home_layout_view);
        message_layout_view = (LinearLayout) findViewById(R.id.message_layout_view);
        pond_layout_view = (LinearLayout) findViewById(R.id.pond_layout_view);
        person_layout_view = (LinearLayout) findViewById(R.id.person_layout_view);
        home_image_view = (ImageView) findViewById(R.id.home_image_view);
        message_image_view = (ImageView) findViewById(R.id.message_image_view);
        pond_image_view = (ImageView) findViewById(R.id.pond_image_view);
        person_image_view = (ImageView) findViewById(R.id.person_image_view);
    }

    //设置点击后的图片颜色为亮色, 设置Fragment内容区域的
    private void setSelect (int a){
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction transaction = fm.beginTransaction();
        HideFragment(transaction);
        switch (a){
            case 0 :
                if (home == null){
                    home = new Home_fragment();
                    transaction.add(R.id.content,home);
                } else {
                    transaction.show(home);
                }
                home_image_view.setImageResource(R.drawable.comui_tab_home_selected);
                break;
            case 1 :
                if (message == null){
                    message = new Message_fragment();
                    transaction.add(R.id.content,message);
                } else {
                    transaction.show(message);
                }
                message_image_view.setImageResource(R.drawable.comui_tab_message_selected);
                break;
            case 2 :
                if (pond == null){
                    pond = new Pond_fragment();
                    transaction.add(R.id.content,pond);
                } else {
                    transaction.show(pond);
                }
                pond_image_view.setImageResource(R.drawable.comui_tab_pond_selected);
                break;
            case 3 :
                if (person == null){
                    person = new Person_fragment();
                    transaction.add(R.id.content,person);
                } else {
                    transaction.show(person);
                }
                person_image_view.setImageResource(R.drawable.comui_tab_person_selected);
                break;
            default:
                break;
        }
        transaction.commit();
    }

    private void HideFragment(FragmentTransaction transaction) {
        if (home != null){
            transaction.hide(home);
        }
        if (message != null){
            transaction.hide(message);
        }
        if (pond != null){
            transaction.hide(pond);
        }
        if (person != null){
            transaction.hide(person);
        }
    }

    //实现点击判断
    @Override
    public void onClick(View v) {
        Resetimg();
        switch (v.getId()){
            case R.id.home_layout_view :
                setSelect(0);
                break;
            case R.id.message_layout_view :
                setSelect(1);
                break;
            case R.id.pond_layout_view :
                setSelect(2);
                break;
            case R.id.person_layout_view :
                setSelect(3);
                break;
            default:
                break;
        }
    }

    //将所有的图片初始化成灰色
    private void Resetimg() {
        home_image_view.setImageResource(R.drawable.comui_tab_home);
        message_image_view.setImageResource(R.drawable.comui_tab_message);
        pond_image_view.setImageResource(R.drawable.comui_tab_pond);
        person_image_view.setImageResource(R.drawable.comui_tab_person);
    }
}