我的Android之路——底部菜单栏的实现

<LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <FrameLayout
            android:id="@+id/fl_content"
            android:layout_width="match_parent"
            android:background="#ffffff"
            android:layout_height="0dp"
            android:layout_weight="1">
        </FrameLayout>

        <include layout="@layout/activity_bottom"/>
    </LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:background="?attr/colorPrimary"
      >

     <LinearLayout
         android:id="@+id/ll_home"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_weight="1"
         android:gravity="center"
         android:orientation="vertical" >

         <ImageView
             android:id="@+id/iv_home"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:src="@drawable/tab_home_pressed" />

         <TextView
             android:id="@+id/tv_home"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="3dp"
             android:text="首页"
             android:textColor="#1B940A"
             android:textStyle="bold" />
     </LinearLayout>

     <LinearLayout
         android:id="@+id/ll_find"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_weight="1"
         android:gravity="center"
         android:orientation="vertical" >

         <ImageView
             android:id="@+id/iv_find"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:src="@drawable/tab_find_normal" />

         <TextView
             android:id="@+id/tv_find"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="3dp"
             android:text="发现"
             android:textColor="#ffffff"
             android:textStyle="bold" />
     </LinearLayout>

     <LinearLayout
         android:id="@+id/ll_recommend"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_weight="1"
         android:gravity="center"
         android:orientation="vertical" >

         <ImageView
             android:id="@+id/iv_recommend"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:src="@drawable/tab_recommend_normal" />

         <TextView
             android:id="@+id/tv_recommend"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="3dp"
             android:text="推荐"
             android:textColor="#ffffff"
             android:textStyle="bold" />
     </LinearLayout>

     <LinearLayout
         android:id="@+id/ll_discuss"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_weight="1"
         android:gravity="center"
         android:orientation="vertical" >

         <ImageView
             android:id="@+id/iv_discuss"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:src="@drawable/tab_discuss_normal" />

         <TextView
             android:id="@+id/tv_discuss"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="3dp"
             android:text="讨论"
             android:textColor="#ffffff"
             android:textStyle="bold" />
     </LinearLayout>

</LinearLayout>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent">

     <ScrollView
         android:layout_width="match_parent"
         android:layout_height="wrap_content">
         <LinearLayout
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:orientation="vertical">

         </LinearLayout>
     </ScrollView>
     <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="我是首页"
        android:textSize="30dp" />

</RelativeLayout>

package com.example.liu.cakeapp;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * Created by lenovo on 2016/9/8.
 */
public class HomeFragment extends Fragment {
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle saveInstanceState){
        return inflater.inflate(R.layout.home,container,false);
    }
}

package com.example.liu.cakeapp;

import android.app.SearchManager;
import android.content.Context;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.widget.SearchView;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener , View.OnClickListener {

    //底部菜单四个LinearLayout
    private LinearLayout ll_home;
    private LinearLayout ll_find;
    private LinearLayout ll_recommend;
    private LinearLayout ll_discuss;

    //底部菜单四个ImageView
    private ImageView iv_home;
    private ImageView iv_find;
    private ImageView iv_recommend;
    private ImageView iv_discuss;

    //底部菜单四个菜单标题
    private TextView tv_home;
    private TextView tv_find;
    private TextView tv_recommend;
    private TextView tv_discuss;

    //四个Fragment
    private Fragment homeFragment;
    private Fragment findFragment;
    private Fragment recommendFragment;
    private Fragment discussFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //初始化控件
        initView();
        // 初始化底部按钮事件
        initEvent();
        // 初始化并设置当前Fragment
        initFragment(0);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);

        SearchManager searchManager=(SearchManager)getSystemService(Context.SEARCH_SERVICE);
        SearchView searchView=(SearchView)menu.findItem(R.id.toolbar_search).getActionView();
        searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.event) {
            return true;
        }else if(id == R.id.jump)
        {
            return true;
        }else if(id == R.id.event)
        {
            return true;
        }else if(id == R.id.event)
        {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_camera) {
            // Handle the camera action
        } else if (id == R.id.nav_gallery) {

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_manage) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    private void initFragment(int index){
        FragmentManager fragmentManager=getSupportFragmentManager();
        FragmentTransaction transaction=fragmentManager.beginTransaction();
        //隐藏所有Fragment
        hideFragment(transaction);
        switch(index){
            case 0:
                if(homeFragment == null){
                    homeFragment=new HomeFragment();
                    transaction.add(R.id.fl_content, homeFragment);
                }else{
                    transaction.show(homeFragment);
                }
                break;
            case 1:
                if(findFragment == null){
                    findFragment=new FindFragment();
                    transaction.add(R.id.fl_content, findFragment);
                }else{
                    transaction.show(findFragment);
                }
                break;
            case 2:
                if(recommendFragment == null){
                    recommendFragment=new RecommendFragment();
                    transaction.add(R.id.fl_content, recommendFragment);
                }else{
                    transaction.show(recommendFragment);
                }
                break;
            case 3:
                if(discussFragment == null){
                    discussFragment=new DiscussFragment();
                    transaction.add(R.id.fl_content, discussFragment);
                }else{
                    transaction.show(discussFragment);
                }
                break;
            default:
                break;
        }
        transaction.commit();
    }
    //隐藏Fragment
    private void hideFragment(FragmentTransaction transaction) {
         if (homeFragment != null) {
             transaction.hide(homeFragment);
         }
         if (findFragment != null) {
             transaction.hide(findFragment);
         }
         if (recommendFragment != null) {
             transaction.hide(recommendFragment);
         }
         if (discussFragment != null) {
             transaction.hide(discussFragment);
         }
     }
    private void initEvent(){
        ll_home.setOnClickListener(this);
        ll_find.setOnClickListener(this);
        ll_recommend.setOnClickListener(this);
        ll_discuss.setOnClickListener(this);
    }

    private void initView(){
        this.ll_home=(LinearLayout)findViewById(R.id.ll_home);
        this.ll_find=(LinearLayout)findViewById(R.id.ll_find);
        this.ll_recommend=(LinearLayout)findViewById(R.id.ll_recommend);
        this.ll_discuss=(LinearLayout)findViewById(R.id.ll_discuss);

        this.iv_home=(ImageView)findViewById(R.id.iv_home);
        this.iv_find=(ImageView)findViewById(R.id.iv_find);
        this.iv_recommend=(ImageView)findViewById(R.id.iv_recommend);
        this.iv_discuss=(ImageView)findViewById(R.id.iv_discuss);

        this.tv_home=(TextView)findViewById(R.id.tv_home);
        this.tv_find=(TextView)findViewById(R.id.tv_find);
        this.tv_recommend=(TextView)findViewById(R.id.tv_recommend);
        this.tv_discuss=(TextView)findViewById(R.id.tv_discuss);
    }

    public void onClick(View v){
        //在每次点击后将所有的底部按钮颜色改变为灰色，然后根据点击着色
        restartBotton();
        //ImageView和TetxView设置为绿色，页面随之跳转
        switch (v.getId()){
            case R.id.ll_home:
                iv_home.setImageResource(R.drawable.tab_home_pressed);
                tv_home.setTextColor(0xff1B940A);
                initFragment(0);
                break;
            case R.id.ll_find:
                iv_find.setImageResource(R.drawable.tab_find_pressed);
                tv_find.setTextColor(0xff1B940A);
                initFragment(1);
                break;
            case R.id.ll_recommend:
                iv_recommend.setImageResource(R.drawable.tab_recommend_pressed);
                tv_recommend.setTextColor(0xff1B940A);
                initFragment(2);
                break;
            case R.id.ll_discuss:
                iv_discuss.setImageResource(R.drawable.tab_discuss_pressed);
                tv_discuss.setTextColor(0xff1B940A);
                initFragment(3);
                break;
            default:
                break;
        }
    }
    public void restartBotton(){
        iv_home.setImageResource(R.drawable.tab_home_normal);
        iv_find.setImageResource(R.drawable.tab_find_normal);
        iv_recommend.setImageResource(R.drawable.tab_recommend_normal);
        iv_discuss.setImageResource(R.drawable.tab_discuss_normal);

        tv_home.setTextColor(0xffffffff);
        tv_find.setTextColor(0xffffffff);
        tv_recommend.setTextColor(0xffffffff);
        tv_discuss.setTextColor(0xffffffff);
    }
}