Android——《第一行代码（第二码）》4.5碎片的最佳实践代码_android第一行代码(第2版)服务的最佳实践-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_45815991/article/details/119418017

简易版新闻的理解

请添加图片描述

MainActivity调用根据屏幕大小调用布局：

单页模式：RecyclerView显示新闻标题，有点击传递数据进入NewContentActivity，其布局中是静态Fragment
双页模式：
1. 左侧：RecyclerView显示新闻标题
2. 右侧：根据左侧的点击，获得NewContentFragment对象刷新

News.java

package com.example.fragmentbestpractice;

public class News {
    private String title;
    private String content;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

news_item.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/news_title"
    android:maxLines="1"
    android:ellipsize="end"
    android:textSize="18sp"
    android:paddingLeft="10dp"
    android:paddingRight="10dp"
    android:paddingTop="15dp"
    android:paddingBottom="15dp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

</TextView>

news_title_frag.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/news_title_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</androidx.recyclerview.widget.RecyclerView>ja

NewsContentFragment.java

package com.example.fragmentbestpractice;

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

import androidx.fragment.app.Fragment;

/*新闻内容碎片*/
public class NewsContentFragment extends Fragment {
    private View view;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        /*新闻内容布局*/
        view = inflater.inflate(R.layout.news_content_frag, container, false);
        return view;
    }

    /**
     *
     * @param newsTitle 新闻标题
     * @param newsContent 内容控件
     */
    public void refresh(String newsTitle, String newsContent)
    {
        View visibilityLayout = view.findViewById(R.id.visibility_layout);
        visibilityLayout.setVisibility(View.VISIBLE);

        TextView newsTitleText = view.findViewById(R.id.news_title);
        TextView newsContentText = view.findViewById(R.id.news_content);
        newsTitleText.setText(newsTitle);
        newsContentText.setText(newsContent);
    }
}

news_content_frag.xml

<?xml version="1.0" encoding="utf-8"?>
<!--新闻内容-->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:id="@+id/visibility_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:visibility="invisible">
        <!--标题-->
        <TextView
            android:id="@+id/news_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:padding="10dp"
            android:textSize="20sp" />
        <!--分隔线-->
        <View
            android:layout_width="match_parent"
            android:layout_height="1dp"
            android:background="#000" />
        <!--内容-->
        <TextView
            android:id="@+id/news_content"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:padding="15dp"
            android:textSize="18sp" />

    </LinearLayout>
    <View
        android:layout_width="1dp"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:background="#000"/>
</RelativeLayout>

news_content.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <!--静态加载-->
    <fragment
        android:id="@+id/news_content_fragment"
        android:name="com.example.fragmentbestpractice.NewsContentFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

NewsContentActivity.java

package com.example.fragmentbestpractice;

import androidx.appcompat.app.AppCompatActivity;

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

public class NewsContentActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.news_content);
        String newsTitle = getIntent().getStringExtra("news_title");
        String newsContent = getIntent().getStringExtra("news_content");
        NewsContentFragment newsContentFragment = (NewsContentFragment) getSupportFragmentManager().findFragmentById(R.id.news_content_fragment);
        newsContentFragment.refresh(newsTitle, newsContent);
    }

    /**
     * 写在跳转到的Activity中
     * @param context 开始跳转的Activity
     * @param newsTitle 标题
     * @param newsContent 内容
     */
    public static void actionStar(Context context, String newsTitle, String newsContent){
        Intent intent = new Intent(context, NewsContentActivity.class);
        intent.putExtra("news_title", newsTitle);
        intent.putExtra("news_content", newsContent);
        context.startActivity(intent);
    }
}

MainActivity.java

package com.example.fragmentbestpractice;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        /*引用的是一个FrameLayout，其中有一个静态加载的fragment*/
        setContentView(R.layout.activity_main);
    }
}

activity_main.xml单页

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
    tools:context=".MainActivity">

    <!--main_activity加载这个碎片会去调用他的onCreateView之类的方法，静态调用-->
    <fragment
        android:id="@+id/news_title_fragment"
        android:name="com.example.fragmentbestpractice.NewsTitleFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</FrameLayout>

双页

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

    <!--静态加载左边的标题布局-->
    <fragment
        android:id="@+id/news_title_fragment"
        android:name="com.example.fragmentbestpractice.NewsTitleFragment"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="match_parent"/>
    <!--帧布局，用来显示右边的内容-->
    <FrameLayout
        android:id="@+id/news_content_layout"
        android:layout_width="0dp"
        android:layout_weight="3"
        android:layout_height="match_parent">
        <!--静态加载右边的内容碎片-->
        <fragment
            android:id="@+id/news_content_fragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:name="com.example.fragmentbestpractice.NewsContentFragment"/>
    </FrameLayout>
</LinearLayout>