android 编程 4.5
注：以下新建文件所有.java的全在mainactivity.java旁边，xml文件全在layout文件夹下。先在gradle里添加依赖compile 'com.android.support:recyclerview-v7:26.+'
同步以后再新建个储存数据的类News.javapackage com.example.xinwei.fragmentbestpractise;
/**
* Created by xinwei on 2017/10/6.
*/
public class News {
public String getTitle() {
return title;
}
public String getContent() {
return content;
}
public void setTitle(String title) {
this.title = title;
}
public void setContent(String content) {
this.content = content;
}
private String title;
private String content;
}
然后新建个布局文件news_content_frag.xml<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/visibility_layout"
android:orientation="vertical"
android:visibility="invisible">
<TextView
android:id="@+id/news_title"
android:gravity="center"
android:padding="10dp"
android:textSize="20sp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#000" />
<TextView
android:id="@+id/news_content"
android:padding="15dp"
android:textSize="18sp"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>
<View
android:layout_width="1dp"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:background="#000" />
</RelativeLayout>
再新建个NewsContentFragment.java文件package com.example.xinwei.fragmentbestpractise;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
/**
* Created by xinwei on 2017/10/6.
*/
public class NewsContentFragment extends Fragment {
private View view;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable 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=view.findViewById(R.id.news_title);
TextView newsContentText=view.findViewById(R.id.news_content);
newsTitleText.setText(newsTitle);
newsContentText.setText(newsContent);
}
}
然后新建个NewsContentActivity.java的活动，把自动创建的布局名设置为news_content,把news_content.xml文件修改为<?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"
>
<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/news_content_fragment"
android:name="com.example.xinwei.fragmentbestpractise.NewsContentFragment" />
</LinearLayout>
然后修改NewsContentActivity.javapackage com.example.xinwei.fragmentbestpractise;
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);
}
}
继续创建个布局文件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:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/news_title_recycler_view"/>
</LinearLayout>
在新建个news_item.xml布局文件作为recyclerveiw的子项<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/news_title"
android:singleLine="true"
android:ellipsize="end"
android:textSize="18sp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="15dp"
android:paddingBottom="15dp" />
然后再新建个NewsTitleFragment.java文件package com.example.xinwei.fragmentbestpractise;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by xinwei on 2017/10/6.
*/
public class NewsTitleFragment extends Fragment {
private boolean isTwoPane;
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if(getActivity().findViewById(R.id.news_content_layout)!=null){
isTwoPane=true;
}else{
isTwoPane=false;
}
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.news_title_frag,container,false);
return view;
}
}
修改activity_main.xml文件<?xml version="1.0" encoding="utf-8"?>
<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.example.xinwei.fragmentbestpractise.NewsTitleFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>
然后在res目录下新建layout-sw600dp文件夹,在这个目录下新建activity_main.xml文件<?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">
<fragment
android:id="@+id/news_title_fragment"
android:name="com.example.xinwei.fragmentbestpractise.NewsTitleFragment"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent" />
<FrameLayout
android:id="@+id/news_content_layout"
android:layout_width="0dp"
android:layout_weight="3"
android:layout_height="match_parent">
<fragment
android:id="@+id/news_content_fragment"
android:name="com.example.xinwei.fragmentbestpractise.NewsContentFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</FrameLayout>
</LinearLayout>
然后再修改NewsTitleFragment.java文件package com.example.xinwei.fragmentbestpractise;
import android.os.Bundle;
import android.support.annotation.Nullable;
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 xinwei on 2017/10/6.
*/
public class NewsTitleFragment extends Fragment {
private boolean isTwoPane;
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if(getActivity().findViewById(R.id.news_content_layout)!=null){
isTwoPane=true;
}else{
isTwoPane=false;
}
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable 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 newsAdapter=new NewsAdapter(getNews());
newsTitleRecyclerView.setAdapter(newsAdapter);
return view;
}
private List<News> getNews(){
List<News> newsList=new ArrayList<>();
for(int i=1;i<=50;i++){
News news=new News();
news.setTitle("This is news title"+i);
news.setContent(getRandomLengthContent("This is news content"+i+"."));
newsList.add(news);
}
return newsList;
}
private String getRandomLengthContent(String content){
Random random=new Random();
int length=random.nextInt(20)+1;
StringBuilder builder=new StringBuilder();
for(int i=0;i<length;i++){
builder.append(content);
}
return builder.toString();
}
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=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(isTwoPane){
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(NewsAdapter.ViewHolder holder, int position) {
News news=mNewsList.get(position);
holder.newsTitleText.setText(news.getTitle());
}
@Override
public int getItemCount() {
return mNewsList.size();
}
}
}
哎！终于写完了，这个其实不用自己写，太麻烦了，我就写了一上午。只要大概看懂了什么意思就行了，我觉得主要是理解。效果图为：
页:
[1]