Android 底部按钮BottomNavigationView + Fragment 的使用（二）

这里来试验BottomNavigationView + Fragment

底部按钮通过点击底部选项，实现中间的Fragment进行页面的切换。

使用BottomNavigationView 控件，实现底部按钮的布局，然后给按钮加上监听，监听选择后，实现中间Fragment页面的切换

上代码：found_main.xml 其他两个文件为menu_main.xml 和 user_main.xml ，从found_main.xml copy 过去就行，修改下里面的样式，便于区分。

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout

    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_height="match_parent">

   <!--用来显示具体内容-->
<LinearLayout

        android:id="@+id/linearLayout2"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:orientation="horizontal"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent">
<TextView

            android:id="@+id/titlename"

            android:layout_width="match_parent"

            android:layout_height="45dp"

            android:layout_weight="1"

            android:background="#2b5361"

            android:drawablePadding="3dp"

            android:gravity="center"

            android:text="发现" />
</LinearLayout>
<LinearLayout

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_marginTop="45dp"

        android:background="@android:color/holo_blue_bright"

        android:orientation="vertical"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/linearLayout2">
<ImageView

            android:id="@+id/imageView2"

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            app:srcCompat="@android:drawable/arrow_down_float" />

    </LinearLayout>
</android.support.constraint.ConstraintLayout>

创建主页面，activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout 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:id="@+id/container"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MenuActivity">
<FrameLayout

        android:id="@+id/FramePage"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:background="@android:color/holo_purple"

        app:layout_constraintBottom_toTopOf="@+id/viewline">
</FrameLayout>
<View

        android:id="@+id/viewline"

        android:layout_width="match_parent"

        android:layout_height="5dp"

        android:layout_above="@id/navigation"

        android:background="@android:color/darker_gray"

        app:layout_constraintBottom_toTopOf="@+id/navigation" />
<android.support.design.widget.BottomNavigationView

        android:id="@+id/navigation"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:background="?android:attr/windowBackground"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintLeft_toLeftOf="parent"

        app:layout_constraintRight_toRightOf="parent"

        app:menu="@menu/navigation" />
</android.support.constraint.ConstraintLayout>

创建BottomNavigationView需要显示的item文件 nabigation.xml

<?xml version="1.0" encoding="utf-8"?>

<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item

        android:id="@+id/navigation_home"

        android:icon="@drawable/ic_home_black_24dp"

        android:title="@string/title_home" />
<item

        android:id="@+id/navigation_dashboard"

        android:icon="@drawable/ic_dashboard_black_24dp"

        android:title="@string/title_dashboard" />
<item

        android:id="@+id/navigation_notifications"

        android:icon="@drawable/ic_notifications_black_24dp"

        android:title="@string/title_notifications" />
</menu>

最后上主程序 MenuActivity.java

package action.sun.com.hello;
import android.app.FragmentManager;

import android.app.FragmentTransaction;

import android.os.Bundle;

import android.support.annotation.NonNull;

import android.support.design.widget.BottomNavigationView;

import android.support.v4.view.ViewPager;

import android.support.v7.app.AppCompatActivity;

import android.util.Log;

import android.view.MenuItem;

import android.widget.FrameLayout;

import android.widget.TextView;
import action.sun.com.hello.action.sun.com.hello.until.FirstFragment;
public class MenuActivity extends AppCompatActivity {
private  String className= "MenuActivity";

  //  private ViewPager viewPager;

    String msg = "Android : ";

    //继承Activity 不会显示APP头上的标题

    private FirstFragment f1,f2,f3;
@Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_menu);
final BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.navigation);
//bottomNavigationView Item 选择监听

       bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {

            @Override

            public boolean onNavigationItemSelected(@NonNull MenuItem item) {

                Log.d("123", "onNavigationItemSelected is click: ");

                FragmentTransaction transaction = getFragmentManager().beginTransaction();

                hideAllFragment(transaction);

                switch (item.getItemId()){

                    case R.id.navigation_home:

                        Log.d(className, "R.id.navigation_home: ");

                        if(f1==null){

                            f1 = FirstFragment.newInstance("发现",R.layout.found_main);

                            transaction.add(R.id.FramePage,f1);

                        }else{

                            transaction.show(f1);

                        }

                        break;

                    case R.id.navigation_dashboard:

                        Log.d(className, "R.id.navigation_dashboard: ");

                        if(f2==null){

                            f2 =FirstFragment.newInstance("我的",R.layout.user_main);//"第二个Fragment"

                            transaction.add(R.id.FramePage,f2);

                        }else{

                            transaction.show(f2);

                        }

                        break;

                    case R.id.navigation_notifications:

                        Log.d(className, "R.string.title_notification: ");

                        if(f3==null){

                            f3 = FirstFragment.newInstance("关于",R.layout.menu_main);//"第三个Fragment"

                            transaction.add(R.id.FramePage,f3);

                        }else{

                            transaction.show(f3);

                        }

                        break;

                }

                transaction.commit();

                Log.d(msg, "xxxxx ");
return false;

            }

        });
}
//隐藏所有Fragment

    public void hideAllFragment(FragmentTransaction transaction){

        if(f1!=null){

            transaction.hide(f1);

        }

        if(f2!=null){

            transaction.hide(f2);

        }

        if(f3!=null){

            transaction.hide(f3);

        }
}
}

FirstFragment.java

package action.sun.com.hello.action.sun.com.hello.until;
import android.graphics.drawable.Drawable;

import android.support.annotation.Nullable;

import android.app.Fragment;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

import android.os.Bundle;
import action.sun.com.hello.R;
public class FirstFragment extends Fragment{
private String context="xxxxxxxxxxxxx";

    private TextView mTextView;

    //要显示的页面

    private int FragmentPage;
public  static  FirstFragment newInstance(String context,int iFragmentPage){
FirstFragment myFragment = new FirstFragment();

        myFragment.context = context;

        myFragment.FragmentPage = iFragmentPage;

        return  myFragment;

    }
@Nullable

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        this.context = context;

        View view = inflater.inflate(FragmentPage,container,false);

        //mTextView = (TextView)view.findViewById(R.id.titlename);

        //mTextView = (TextView)getActivity().findViewById(R.id.txt_content);

        ///mTextView.setText(context);

        //mTextView.setBackgroundColor(20);

        return view;

    }

}

到此，代码结束，可实现上面的效果。