APP学习10（Fragment碎片）

1. Fragment碎片

方式1：通过控件实现。

实现点击饮料，隔壁的文本进行切换。

 

 

 代码：主要添加的代码在于fragment_left.java中

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    >


   <fragment
       android:name="com.example.myapp.fragment_Menu"
       android:id="@+id/fragment1"
       android:layout_width="0dp"
       android:layout_height="match_parent"
       android:layout_weight="1"
       ></fragment>
   <fragment
       android:name="com.example.myapp.fragment_info"
       android:id="@+id/fragment2"
       android:layout_width="0dp"
       android:layout_height="match_parent"
       android:layout_weight="2"
       ></fragment>
</LinearLayout>

left_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="@color/teal_700">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btn1"
        android:backgroundTint="@color/purple_200"
        android:text="烤串"
        android:textSize="30sp"></Button>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btn2"
        android:backgroundTint="@color/purple_200"
        android:text="饮料"
        android:textSize="30sp"></Button>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btn3"
        android:backgroundTint="@color/purple_200"
        android:text="主食"
        android:textSize="30sp"></Button>

</LinearLayout>

right_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <TextView
        android:id="@+id/info"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="sk"
        android:textSize="40sp"
        ></TextView>

</LinearLayout>

fragment_left.java

package com.example.myapp;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;

//Fragment_Menu类将碎片和对应的布局产生关联
public class fragment_Menu extends Fragment {
    @Nullable
    @Override
    //通过onCreateView用于构建某个碎片和布局的关联
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.left_layout,container,false);
        Button btn2=v.findViewById(R.id.btn2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //找到mainActivity对象
                MainActivity m1 = (MainActivity) getActivity();
                //通过m1找到碎片管理器
                FragmentManager fm = m1.getSupportFragmentManager();
                //通过fm获取右边的碎片
                Fragment f1=fm.findFragmentById(R.id.fragment2);
                //通过f1找到右边对应的布局
                View v1=f1.getView();
                TextView t1=v1.findViewById(R.id.info);
                t1.setText("可乐、雪碧、茉莉花茶");
            }
        });
        return v;
    }
}

 

方式2：主要改变在layout_main.xml和fragment_Menu.java(里面把内容删掉，直接返回view就好了)还有MainActivity.java文件。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    >

   <FrameLayout
      android:id="@+id/left"
       android:layout_width="0dp"
       android:layout_height="match_parent"
      android:layout_weight="1"></FrameLayout>
   <FrameLayout
      android:id="@+id/right"
       android:layout_width="0dp"
       android:layout_height="match_parent"
      android:layout_weight="2"></FrameLayout>

</LinearLayout>

MainActivity.java

package com.example.myapp;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.os.Bundle;



public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取碎片管理器
        FragmentManager fm=this.getSupportFragmentManager();
        //获取碎片事物对象
        FragmentTransaction ft = fm.beginTransaction();
        ft.add(R.id.left,new fragment_Menu());
        ft.add(R.id.right,new fragment_info());
        //事务设置之后必须运行commit（）方法，提交事务
        ft.commit();
    }



}

fragmnet_Menu.java

package com.example.myapp;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;

//Fragment_Menu类将碎片和对应的布局产生关联
public class fragment_Menu extends Fragment {
    @Nullable
    @Override
    //通过onCreateView用于构建某个碎片和布局的关联
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.left_layout,container,false);
        return v;
    }
}

实现结果和方式一一样。