10.Fragment与ViewPager

作者: 为梦想战斗 | 来源:发表于2017-10-15 19:20 被阅读0次

1.Fragment简单用法
建left和right的xml文件：

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

    <Button
        android:id="@+id/button"
        android:layout_gravity="center_horizontal"
        android:text="button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

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

    <TextView
        android:layout_gravity="center_horizontal"
        android:text="HAHA"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

建立left和right的类：

public class Left extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inf, ViewGroup container, Bundle savedInstanceState) {
        View view = inf.inflate(R.layout.left,container,false);
        return view;
    }
}
public class Right1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inf, ViewGroup container, Bundle savedInstanceState) {
        View view = inf.inflate(R.layout.right1,container,false);
        return view;
    }
}

修改activity_main.xml：

<?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:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/left_fragment"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_weight="1" />

    <fragment
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/right_fragment"
        android:name="com.lewanjiang.fragmenttest.Right"
        android:layout_weight="1" />

</LinearLayout>

动态添加Fragment：
建Right1.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">

    <TextView
        android:text="HEIHEI"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</LinearLayout>

建Right1类：

public class Right1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inf, ViewGroup container, Bundle savedInstanceState) {
        View view = inf.inflate(R.layout.right1,container,false);
        return view;
    }
}

修改activity_main.xml：

<?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:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/left_fragment"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_weight="1" />

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

    </FrameLayout>
</LinearLayout>

修改MainActivity:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button = (Button) findViewById(R.id.button);
        replaceFragment(new Right());
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                replaceFragment(new Right1());
            }
        });
    }

    private void replaceFragment(Fragment fra) {
        FragmentManager fraMan = getSupportFragmentManager();
        FragmentTransaction tra = fraMan.beginTransaction();
        tra.replace(R.id.right_layout,fra);
        tra.commit();
    }
}

完成。

模拟返回栈：

tra.addToBackStack(null);

活动调用碎片中方法：

Right rigFra = (Right) getFragmentManager().findFragmentById(R.id.right);

碎片调用活动中方法：
在碎片中：

MainActivity act = (MainActivity) getActivity();

同时也可以使用这个方法获取Context。

fragment生命周期：onAttach(),onCreate(),onCreateView(),onActivityCreate(),onStart(),onResume(),onPause(),onStop(),onDestroyView(),onDestroy(),onDetach()

根据设备屏幕大小方向动态选择加载哪个布局：
修改activity_main.xml文件：

<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:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/left_fragment"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_weight="1" />
</LinearLayout>

在res目录下新建layout_large文件夹,新建名为：activity_main.xml的布局：

<?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:id="@+id/left"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1" />
    <fragment
        android:id="@+id/right"
        android:name="com.lewanjiang.fragmenttest.Right"
        android:layout_height="match_parent"
        android:layout_width="0dp"
        android:layout_weight="3" />
</LinearLayout>

最小宽度限定符：
新建layout-sw600dp文件夹。

综合应用——新闻应用：
1。build.gradle 中添加recyclerview支持
2.新建新闻类：News

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;
    }
}

3.新建内容布局文件news_content_frag.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">

    <LinearLayout
        android:id="@+id/visibility_layout"
        android:orientation="vertical"
        android:visibility="invisible"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            android:id="@+id/news_title"
            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:layout_weight="1"
            android:textSize="18sp"
            android:layout_width="match_parent"
            android:layout_height="0dp"/>

    </LinearLayout>

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

4.新建内容布局类NewsContentFragment，继承Fragment:

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);
    }
}

5.对小屏模式支持，新建Activity:NewsContentAcitivty和相应布局文件news_content.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.fragmentbestpractice.NewsContentActivity">

    <fragment
        android:id="@+id/news_content_fragment"
        android:name="com.lewanjiang.fragmentbestpractice.NewsContentFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>
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);
    }

    public static void actionStart(Context context,String newsTitle,String newsContent) {
        Intent intent = new Intent(context,NewsContentActivity.class);
        intent.putExtra("news_title",newsTitle);
        intent.putExtra("new_content",newsContent);
        context.startActivity(intent);
    }
}

6.新建用于显示新闻列表的布局，news_title_frag.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">

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

7.新建news_item.xml作为recyclerview的子布局：

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/news_title"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
        />

8.新建NewsTitleFragment作为展示新闻列表的碎片：

public class NewsTitleFragment extends Fragment {
    private boolean isTwoPane;

    @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=1;i<=50;i++) {
            News news = new News();
            news.setTitle("This is news title" + i);
            news.setContent("content" + i);
            newsList.add(news);
        }
        return newsList;
    }

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

    class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.ViewHolder> {
        private List<News> mNewsList;

        class ViewHolder extends RecyclerView.ViewHolder {
            TextView newsTitleText;
            public ViewHolder(View view) {
                super(view);
                newsTitleText = (TextView)view.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 v) {
                    News news = mNewsList.get(holder.getAdapterPosition());
                    if (isTwoPane) {
                        NewsContentFragment newsContentFragment = (NewsContentFragment)getFragmentManager().findFragmentById(R.id.news_content_fragment);
                        newsContentFragment.refresh(news.getTitle(),news.getContent());
                        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();
        }
    }
}

9.修改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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.fragmentbestpractice.MainActivity">

    <fragment
        android:id="@+id/news_title_fragment"
        android:name="com.lewanjiang.fragmentbestpractice.NewsTitleFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>

10.新建layout-sw600dp支持大屏，在此文件夹下新建activity_main：

<?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.lewanjiang.fragmentbestpractice.NewsTitleFragment"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="match_parent" />
    <FrameLayout
        android:id="@+id/news_content_layout"
        android:layout_weight="3"
        android:layout_width="0dp"
        android:layout_height="match_parent">

        <fragment
            android:id="@+id/news_content_fragment"
            android:name="com.lewanjiang.fragmentbestpractice.NewsContentFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </FrameLayout>

</LinearLayout>

2.ViewPager

简单用法，修改activity_main.xml，新建三个滑动页面：page0,page1,page2：

<LinearLayout
   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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.viewpager.MainActivity">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        ></android.support.v4.view.ViewPager>

</LinearLayout>


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

    <TextView
        android:text="haha 0"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

新建MyViewpager类和修改MainActivity：

public class MyViewpagerAdapter extends PagerAdapter {
    private List<View> pageList;
    public MyViewpagerAdapter(List<View> pageList) {
        this.pageList = pageList;
    }

    @Override
    public int getCount() {
        return pageList.size();
    }

    @Override
    public boolean isViewFromObject(View view,Object object) {
        return view == object;
    }

    @Override
    public Object instantiateItem(ViewGroup container,int position) {
        container.addView(pageList.get(position));
        return pageList.get(position);
    }

    @Override
    public void destroyItem(ViewGroup container,int position,Object object) {
        container.removeView(pageList.get(position));
    }
}

public class MainActivity extends AppCompatActivity {

    private View page0,page1,page2;
    private List<View> pageList;
    private ViewPager mViewPager;
    private MyViewpagerAdapter mMyViewpagerAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LayoutInflater inflater = getLayoutInflater();
        page0 = inflater.inflate(R.layout.page0,null);
        page1 = inflater.inflate(R.layout.page1,null);
        page2 = inflater.inflate(R.layout.page2,null);
        pageList = new ArrayList<>();
        pageList.add(page0);
        pageList.add(page1);
        pageList.add(page2);
        mViewPager = (ViewPager) findViewById(R.id.viewpager);
        mMyViewpagerAdapter = new MyViewpagerAdapter(pageList);
        mViewPager.setAdapter(mMyViewpagerAdapter);
    }
}

10.Fragment与ViewPager

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