使用RadioButton+Fragment实现底部导航栏

底部导航栏，在我们App项目中是非常常用！而且实现它的方式很多，今天我们就来使用RadioButton+Fragment实现底部导航栏！

下面就让我们动手吧，首先我们打开RadioButtonDemo这个项目，首先修改activity_main.xml文件如下:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.jackhu.radiobuttondemo.MainActivity">

    <FrameLayout
        android:id="@+id/mFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">FrameLayout>

    <RadioGroup
        android:layout_marginBottom="2dp"
        android:id="@+id/mRadioGroup"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="48dp">
        <RadioButton
            android:drawableTop="@drawable/rbhome"
            android:button="@null"
            android:checked="true"
            android:textColor="@color/colorRadioButtonP"
            android:id="@+id/mRb_home"
            android:gravity="center"
            android:layout_width="0dp"
            android:text="Home"
            android:layout_weight="1"
            android:layout_height="match_parent" />

        <RadioButton
            android:drawableTop="@drawable/rb_message"
            android:button="@null"
            android:textColor="@color/colorRadioButtonN"
            android:id="@+id/mRb_message"
            android:gravity="center"
            android:layout_width="0dp"
            android:text="Message"
            android:layout_weight="1"
            android:layout_height="match_parent" />

        <RadioButton
            android:drawableTop="@drawable/rbfind"
            android:button="@null"
            android:textColor="@color/colorRadioButtonN"
            android:id="@+id/mRb_find"
            android:gravity="center"
            android:layout_width="0dp"
            android:text="Find"
            android:layout_weight="1"
            android:layout_height="match_parent" />

        <RadioButton
            android:drawableTop="@drawable/rbmy"
            android:button="@null"
            android:textColor="@color/colorRadioButtonN"
            android:id="@+id/mRb_my"
            android:gravity="center"
            android:layout_width="0dp"
            android:text="My"
            android:layout_weight="1"
            android:layout_height="match_parent" />

    RadioGroup>

LinearLayout>

这里我们在布局文件Fragment控件:用于显示界面的切换。
RadioGroup控件包含了4个RadioButton:用于显示按钮。我们给第一个按钮check为true默认选中。其中android:button=”@null” 取消圆点。

---

drawableTop属性:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_checked="true" android:drawable="@drawable/home_p"/>
    <item android:drawable="@drawable/home_n"/>
selector>

显示选择和未选中的状态的图标

---

创建Fragment，加载Fragment布局文件，类代码如下:

package com.example.jackhu.radiobuttondemo.fragment;


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

import com.example.jackhu.radiobuttondemo.R;

/**
 * A simple {@link Fragment} subclass.
 */
public class HomeFragment extends Fragment {


    public HomeFragment() {
        // Required empty public constructor
    }

    //单例模式
    public static HomeFragment newInstance(){
        HomeFragment homeFragment=new HomeFragment();
        return homeFragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_home, container, false);
    }

}

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接下来我们来修改MainActivity.class中的代码，在这里实现点击按钮切换Fragment的具体功能，代码如下:

package com.example.jackhu.radiobuttondemo;

import android.support.annotation.IdRes;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

import com.example.jackhu.radiobuttondemo.fragment.FindFragment;
import com.example.jackhu.radiobuttondemo.fragment.HomeFragment;
import com.example.jackhu.radiobuttondemo.fragment.MessageFragment;
import com.example.jackhu.radiobuttondemo.fragment.MyFragment;

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

public class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener {

    private RadioGroup mRadioGroup;
    private List fragments = new ArrayList<>();
    private Fragment fragment;
    private FragmentManager fm;
    private FragmentTransaction transaction;
    private RadioButton rb_Home,rb_Message,rb_Find,rb_My;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView(); //初始化组件
        mRadioGroup.setOnCheckedChangeListener(this); //点击事件
        fragments = getFragments(); //添加布局
        //添加默认布局
        normalFragment();
    }

    //默认布局
    private void normalFragment() {
        fm=getSupportFragmentManager();
        transaction=fm.beginTransaction();
        fragment=fragments.get(0);
        transaction.replace(R.id.mFragment,fragment);
        transaction.commit();
    }

    private void initView() {
        mRadioGroup = (RadioGroup) findViewById(R.id.mRadioGroup);
        rb_Home= (RadioButton) findViewById(R.id.mRb_home);
        rb_Message= (RadioButton) findViewById(R.id.mRb_message);
        rb_Find= (RadioButton) findViewById(R.id.mRb_find);
        rb_My= (RadioButton) findViewById(R.id.mRb_my);
    }

    @Override
    public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {
        fm=getSupportFragmentManager();
        transaction=fm.beginTransaction();
        switch (checkedId){
            case R.id.mRb_home:
                fragment=fragments.get(0);
                transaction.replace(R.id.mFragment,fragment);
                Toast.makeText(this, "Home", Toast.LENGTH_SHORT).show();
                break;
            case R.id.mRb_message:
                fragment=fragments.get(1);
                transaction.replace(R.id.mFragment,fragment);
                Toast.makeText(this, "Message", Toast.LENGTH_SHORT).show();
                break;
            case R.id.mRb_find:
                fragment=fragments.get(2);
                transaction.replace(R.id.mFragment,fragment);
                Toast.makeText(this, "Find", Toast.LENGTH_SHORT).show();
                break;
            case R.id.mRb_my:
                fragment=fragments.get(3);
                transaction.replace(R.id.mFragment,fragment);
                Toast.makeText(this, "My", Toast.LENGTH_SHORT).show();
                break;
        }
        setTabState();
        transaction.commit();
    }

    //设置选中和未选择的状态
    private void setTabState() {
        setHomeState();
        setMessageState();
        setFindState();
        setMyState();
    }

    private void setMyState() {
        if (rb_My.isChecked()){
            rb_My.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
        }else{
            rb_My.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
        }
    }

    private void setFindState() {
        if (rb_Find.isChecked()){
            rb_Find.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
        }else{
            rb_Find.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
        }
    }

    private void setMessageState() {
        if (rb_Message.isChecked()){
            rb_Message.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
        }else{
            rb_Message.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
        }
    }

    private void setHomeState() {
        if (rb_Home.isChecked()){
            rb_Home.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonP));
        }else{
            rb_Home.setTextColor(ContextCompat.getColor(this,R.color.colorRadioButtonN));
        }
    }

    public List getFragments() {
        fragments.add(new HomeFragment());
        fragments.add(new MessageFragment());
        fragments.add(new FindFragment());
        fragments.add(new MyFragment());
        return fragments;
    }
}

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好了，这样的话，所有的代码就已经完成了，可以运行一下看看完整的效果了最终效果图: