Android - 实现微信的底部导航功能（第五次作业）

第五次作业-实现微信底部导航功能

题目要求

利用fragment和ViewPager实现类似微信的底部导航功能。上传模拟器运行截图及代码截图。（参考例5-2）

创建工程WeChat

项目工程结构

修改MainActivity布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    xmlns:app="http://schemas.android.com/apk/res-auto">


    <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewPage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1">

    androidx.viewpager.widget.ViewPager>

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tab"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:background="#666666"
        app:tabTextColor="#FFFFFF"
        app:tabIndicatorColor="#FFFFFF">

    com.google.android.material.tabs.TabLayout>

LinearLayout>

⚠️：底部出现导航栏

创建四个fragments并创建对应的布局文件

注意：这里创建的是java文件，而非activity，另外布局文件也需要自己创建。

WeChatFragment

• 布局文件fragment_wechat

  
  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent">
  
      <TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="WeChat界面"
          android:textSize="20sp"
          android:layout_centerInParent="true" />
  
  RelativeLayout>
  

• WeChatFragment.java

  package com.example.wechat.fragments;
  
  import android.os.Bundle;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewGroup;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  import androidx.fragment.app.Fragment;
  
  import com.example.wechat.R;
  
  public class WeChatFragment extends Fragment {
      @Nullable
      @Override
      public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
          return inflater.inflate(R.layout.fragment_wechat,container,false);
      }
  }
  

---

FriendsFragment

• 布局文件fragment_friends

  
  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent">
  
      <TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="朋友界面"
          android:textSize="20sp"
          android:layout_centerInParent="true" />
  
  RelativeLayout>
  

• FriendsFragment.java

  package com.example.wechat.fragments;
  
  import android.os.Bundle;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewGroup;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  import androidx.fragment.app.Fragment;
  
  import com.example.wechat.R;
  
  public class FriendsFragment extends Fragment {
      @Nullable
      @Override
      public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
          return inflater.inflate(R.layout.fragment_friends, container, false);
      }
  }
  

  ---

ConcatFragment

• 布局文件fragment_concat

  
  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent">
  
      <TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="联系人界面"
          android:textSize="20sp"
          android:layout_centerInParent="true" />
  
  RelativeLayout>
  

• ConcatFragment.java

  package com.example.wechat.fragments;
  
  import android.content.Intent;
  import android.os.Bundle;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewGroup;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  import androidx.fragment.app.Fragment;
  
  import com.example.wechat.R;
  
  public class ConcatFragment extends Fragment {
      @Nullable
      @Override
      public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
          return inflater.inflate(R.layout.fragment_concat, container, false);
      }
  }
  

  ---

SettingsFragment

• 布局文件fragment_settings

  
  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="match_parent"
      android:layout_height="match_parent">
  
      <TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="设置界面"
          android:textSize="20sp"
          android:layout_centerInParent="true" />
  
  RelativeLayout>
  

• SettingsFragment.java

  package com.example.wechat.fragments;
  
  import android.os.Bundle;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewGroup;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  import androidx.fragment.app.Fragment;
  
  import com.example.wechat.R;
  
  public class SettingsFragment extends Fragment {
      @Nullable
      @Override
      public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
          return inflater.inflate(R.layout.fragment_settings,container,false);
      }
  }
  

MainActivity.java

package com.example.wechat;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import androidx.viewpager.widget.ViewPager;

import android.content.Intent;
import android.os.Bundle;

import com.example.wechat.fragments.ConcatFragment;
import com.example.wechat.fragments.FriendsFragment;
import com.example.wechat.fragments.SettingsFragment;
import com.example.wechat.fragments.WeChatFragment;
import com.google.android.material.tabs.TabLayout;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

public class MainActivity extends AppCompatActivity {

    private TabLayout tabLayout;
    private ViewPager viewPager;

    List<Fragment> fragments = new ArrayList<>();

    String tabTitles[] = {"微信", "朋友", "通讯录","设置"};

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

        // 初始化TabLayout
        tabLayout = findViewById(R.id.tab);
        viewPager = findViewById(R.id.viewPage);

        //设置ViewPager之后，Tab的内容由ViewPage（适配器）提供
        tabLayout.setupWithViewPager(viewPager);

        fragments.add(new WeChatFragment());
        fragments.add(new FriendsFragment());
        fragments.add(new ConcatFragment());
        fragments.add(new SettingsFragment());


        viewPager.setAdapter(new MyFragmentPagerAdapter(getSupportFragmentManager()));

        //添加选项卡及对应的图标
        Objects.requireNonNull(tabLayout.getTabAt(0)).setIcon(R.drawable.icon_weixin);

        Objects.requireNonNull(tabLayout.getTabAt(1)).setIcon(R.drawable.icon_friends);

        Objects.requireNonNull(tabLayout.getTabAt(2)).setIcon(R.drawable.icon_concat);

        Objects.requireNonNull(tabLayout.getTabAt(3)).setIcon(R.drawable.icon_settings);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        fragments.get(0).onActivityResult(requestCode, resultCode, data);
    }

    class MyFragmentPagerAdapter extends FragmentPagerAdapter {

        //构造器
        public MyFragmentPagerAdapter(@NonNull FragmentManager fm) {
            super(fm, MyFragmentPagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
        }

        @NonNull
        @Override
        public Fragment getItem(int position) {
            return fragments.get(position);
        }

        @Override
        public int getCount() {
            return fragments.size();
        }

        @Nullable
        @Override
        //关联之后的TabLayout中题目(Item)，有ViewPager的适配器方法getPageTitle提供
        public CharSequence getPageTitle(int position) {
            return tabTitles[position];     //展示导航栏文字
        }
    }
}

最终效果展示

补充：

⚠️：导航栏采用的icon图标均取自于阿里巴巴矢量图标库官网

​ 网站链接：https://www.iconfont.cn/

图标格式选择如下：

最终代码区域展示如下图：