Andriod-碎片的实际使用

最新推荐文章于 2021-08-30 10:47:40 发布

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最新推荐文章于 2021-08-30 10:47:40 发布

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分类专栏： android

本文链接：https://blog.youkuaiyun.com/xiaofeng3011/article/details/80754266

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本文介绍了一个基于Android平台的新闻应用程序实现细节，包括MainActivity初始化、新闻数据模型定义、新闻内容展示活动及片段等关键部分。通过NewsTitleFragment展示了新闻标题列表，并在NewsContentFragment中实现了新闻内容的具体显示。

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MainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;


public class MainActivity extends AppCompatActivity {


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

News.java

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;
    }
}

NewsContentActivity.java

import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;


public class NewsContentActivity extends AppCompatActivity {


    public static void actionStart(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);
    }


    @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);
    }
}

NewsContentFragment.java

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


import org.w3c.dom.Text;


/**
 * Created by 13178 on 2018-6-14.
 */


public class NewsContentFragment extends Fragment {
    private View view;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState){
        view = inflater.inflate(R.layout.news_content_frag,container,false);
        return view;
    }


    public void refresh(String newsTitle,String newsContent){
        View visibilityLayout = view.findViewById(R.id.visibility_layout);
        visibilityLayout.setVisibility(View.VISIBLE);
        TextView newsTitleText = (TextView) view.findViewById(R.id.news_title);
        TextView newsContentText = (TextView) view.findViewById(R.id.news_content);
        newsTitleText.setText(newsTitle);
        newsContentText.setText(newsContent);
     }
}

NewsTitleFragment.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;


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


/**
 * Created by 13178 on 2018-6-14.
 */


public class NewsTitleFragment extends Fragment {


    private boolean isTwoPace;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState){
        View view = inflater.inflate(R.layout.news_title_frag,container,false);
        RecyclerView newsTitleRecyclerView = (RecyclerView) view.findViewById(R.id.news_title_recycler_view);
        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        newsTitleRecyclerView.setLayoutManager(layoutManager);
        NewsAdapter adapter = new NewsAdapter(getNews());
        newsTitleRecyclerView.setAdapter(adapter);
        return view;
    }


    private List<News> getNews() {
        List<News> newsList = new ArrayList<>();
        for(int i = 0 ;i<50;i++){
            News news = new News();
            news.setTitle("这是第新闻标题"+i);
            news.setContent(getRandomLengthContent("这是第新闻"+ i +". "));
            newsList.add(news);
        }
        return newsList;
    }


    private String getRandomLengthContent(String s) {
        Random random = new Random();
        int length = random.nextInt(20)+1;
        StringBuilder builder = new StringBuilder();
        for(int i=0;i<length;i++){
            builder.append(s);
        }
        return builder.toString();
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState){
        super.onActivityCreated(savedInstanceState);
        if(getActivity().findViewById(R.id.news_content_layout)!=null) {
            isTwoPace = true;
        }else{
                isTwoPace = false;
        }
    }


    class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.ViewHolder>{
        private List<News> mNewsList;
        class ViewHolder extends RecyclerView.ViewHolder{
            TextView newsTitleText;
            public ViewHolder(View itemView) {
                super(itemView);
                newsTitleText= (TextView) itemView.findViewById(R.id.news_title);
            }
        }


        public NewsAdapter(List<News> newsList){
            mNewsList = newsList;
        }


        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.news_item,parent,false);
            final ViewHolder holder = new ViewHolder(view);
            view.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    News news = mNewsList.get(holder.getAdapterPosition());
                    if(isTwoPace){
                        NewsContentFragment newsContentFragment = (NewsContentFragment)
                                getFragmentManager().findFragmentById(R.id.news_content_fragment);
                        newsContentFragment.refresh(news.getTitle(),news.getContent());
                    }else{
                        NewsContentActivity.actionStart(getActivity(),news.getTitle(),news.getContent());
                    }
                }
            });
            return holder;
        }


        @Override
        public void onBindViewHolder(ViewHolder holder, int position) {
            News news = mNewsList.get(position);
            holder.newsTitleText.setText(news.getTitle());
        }


        @Override
        public int getItemCount() {
            return mNewsList.size();
        }


    }




}

activity_main.xml中

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/news_title_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <fragment
        android:id="@+id/news_title_fragment"
        android:name="com.ldxiaofeng.android.fragmentpractice.NewsTitleFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>




</FrameLayout>

news_content.xml

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


    <fragment
        android:id="@+id/news_content_fragment"
        android:name="com.ldxiaofeng.android.fragmentpractice.NewsContentFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

news_content_frag.xml

<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">


        <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"/>


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


        <TextView
            android:id="@+id/news_content"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:padding="15sp"
            android:textSize="18sp"/>


    </LinearLayout>


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

news_item.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <TextView
        android:id="@+id/news_title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:maxLines="1"
        android:ellipsize="end"
        android:textSize="18sp"
        android:paddingLeft="10dp"
        android:paddingRight="10dp"
        android:paddingBottom="15dp"
        android:paddingTop="15dp"/>
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#000"/>
</RelativeLayout>

news_title_frag.xml

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


    <android.support.v7.widget.RecyclerView
        android:id="@+id/news_title_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />
</LinearLayout>