判断网络封装AsyncTask通过Fragment+Viewpager展示XListView展示多条目数据

最新推荐文章于 2021-06-15 09:39:47 发布

A-Mm

最新推荐文章于 2021-06-15 09:39:47 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/weixin_43915066/article/details/85039968

本文详细介绍了一个基于Android的应用开发过程，从权限配置、依赖管理到UI布局设计，包括使用ListView、Fragment和ViewPager进行内容展示，以及自定义适配器实现数据绑定。同时，介绍了如何利用Gson和Universal Image Loader进行网络数据请求和图片加载，展示了完整的代码实现。

首页注意网络和添加权限

 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

android:name=".app.AppCont"

依赖

implementation 'com.google.code.gson:gson:2.8.5'
implementation 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'

将ListView类和布局和所需图片插入

填写多个fragment

主页面布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <LinearLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        >

        <FrameLayout
            android:id="@+id/main_container_content"
            android:layout_width="match_parent"
            android:background="@color/app_w"
            android:layout_height="0dp"
            android:layout_weight="1"
            />

        <RadioGroup
            android:id="@+id/radioGroup"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            >
            <RadioButton
                android:id="@+id/radioButton0"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:button="@null"
                android:gravity="center"
                android:textColor="@drawable/one"
                android:drawableTop="@drawable/one"
                android:textSize="15sp"
                android:text="@string/app_zy" />
            <RadioButton
                android:id="@+id/radioButton1"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:textColor="@drawable/two"
                android:layout_weight="1"
                android:button="@null"
                android:gravity="center"
                android:drawableTop="@drawable/two"
                android:textSize="15sp"
                android:text="@string/app_gh" />
            <RadioButton
                android:id="@+id/radioButton2"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:textColor="@drawable/three"
                android:button="@null"
                android:gravity="center"
                android:drawableTop="@drawable/three"
                android:textSize="15sp"
                android:text="@string/app_ys" />
            <RadioButton
                android:id="@+id/radioButton3"
                android:layout_width="0dp"
                android:textColor="@drawable/four"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:button="@null"
                android:gravity="center"
                android:drawableTop="@drawable/four"
                android:textSize="15sp"
                android:text="@string/app_sj" />


        </RadioGroup>
    </LinearLayout>
    <LinearLayout
        android:id="@+id/left"
        android:layout_width="200dp"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:layout_gravity="start"

        android:background="@mipmap/www"
        >
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            >
            <ImageView
                android:layout_width="70dp"
                android:layout_height="70dp"
                android:src="@mipmap/tx"
                />
            <TextView
                android:layout_marginTop="12dp"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="15dp"
                android:text="@string/app_mn"
                />
        </LinearLayout>


        <Button
            android:layout_marginTop="15dp"
            android:id="@+id/dd"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/app_homea"/>
        <Button
            android:id="@+id/ss"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/app_xsp"/>
        <Button
            android:id="@+id/kk"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/app_my"/>

    </LinearLayout>
</android.support.v4.widget.DrawerLayout>

MainActivity

package com.beiw.tzk;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.RadioGroup;


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

public class MainActivity extends AppCompatActivity {

    private RadioGroup radio;
    private ZyFragment zyFragment;
    private KxFragment kxFragment;
    private HqFragment hqFragment;
    private MyFragment myFragment;
    private List<Fragment> fragments;
    private FragmentManager fragmentManager;
    private FragmentTransaction transition;
    private ViewPager pager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }
    private void initView() {
        radio = (RadioGroup) findViewById(R.id.radioGroup);
        //fragment 管理器
        fragmentManager = getSupportFragmentManager();
        fragments = new ArrayList<>();
        // 添加首页
        radio.check(R.id.radioGroup);
        zyFragment = new ZyFragment();
        fragments.add(zyFragment);
        hideOthersFragment(zyFragment, true);

        radio.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                switch (checkedId) {
                    // 首页
                    case R.id.radioButton0:
                        hideOthersFragment(zyFragment, false);

                        break;
                    //干货
                    case R.id.radioButton1:
                        if (kxFragment == null) {

                            kxFragment = new KxFragment();
                            fragments.add(kxFragment);
                            hideOthersFragment(kxFragment, true);
                        } else {
                            hideOthersFragment(kxFragment, false);
                        }
                        break;
                    // 影视
                    case R.id.radioButton2:
                        if (hqFragment == null) {
                            hqFragment = new HqFragment();
                            fragments.add(hqFragment);
                            hideOthersFragment(hqFragment, true);
                        } else {
                            hideOthersFragment(hqFragment, false);
                        }
                        break;
                    // 书籍
                    case R.id.radioButton3:

                        if (myFragment == null) {
                            myFragment = new MyFragment();
                            fragments.add(myFragment);
                            hideOthersFragment(myFragment, true);
                        } else {
                            hideOthersFragment(myFragment, false);
                        }
                        break;

                    default:
                        break;
                }
            }
        });
    }

    /**
     * 动态显示Fragment
     *
     * @param showFragment 要增加的fragment
     * @param add          true：增加fragment；false：切换fragment
     */
    private void hideOthersFragment(Fragment showFragment, boolean add) {
        transition = fragmentManager.beginTransaction();
        if (add)
            transition.add(R.id.main_container_content,showFragment);
        for (Fragment fragment : fragments) {
            if (showFragment.equals(fragment)) {
                transition.show(fragment);
            } else {
                transition.hide(fragment);
            }
        }
        transition.commit();
    }


}

适配器

package com.beiw.tzk.adpter;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.beiw.tzk.R;
import com.beiw.tzk.bean.Bean;
import com.nostra13.universalimageloader.core.ImageLoader;

import java.util.List;

public class MySetAdpter extends BaseAdapter{
    final  int left=0;
    final  int right=1;
    final  int center=2;
    public MySetAdpter(Context context, List<Bean.ResultBean.DataBean> data) {
        this.context = context;
        this.mlist = data;
    }

    Context context;
    List<Bean.ResultBean.DataBean> mlist;
    @Override
    public int getCount() {
        return mlist.size();
    }

    @Override
    public Object getItem(int position) {
        return mlist.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public int getItemViewType(int position) {
        switch (position){
                case 0:
                return left;
                case 1:
                return right;
                case 2:
                return center;

        }
        return  position % 2;
    }

    @Override
    public int getViewTypeCount() {
        return 3;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        int type = getItemViewType(position);
        MySetAdpter.ViewHolder vh= new MySetAdpter.ViewHolder();
        if (convertView==null){
             switch (type){
                 case left:
                     convertView=View.inflate(context, R.layout.yibuju,null);
                     vh.t1=convertView.findViewById(R.id.t1);
                     convertView.setTag(vh);
                     break;
                     case right:
                     convertView=View.inflate(context, R.layout.erbuju,null);
                     vh.t2=convertView.findViewById(R.id.t2);
                     vh.i1=convertView.findViewById(R.id.i1);
                     vh.i2=convertView.findViewById(R.id.i2);
                     vh.i3=convertView.findViewById(R.id.i3);
                     convertView.setTag(vh);
                     break;
                     case center:
                     convertView=View.inflate(context, R.layout.sanbuju,null);
                     vh.t3=convertView.findViewById(R.id.t3);
                     vh.i4=convertView.findViewById(R.id.i4);
                     convertView.setTag(vh);
                     break;
             }
        }else {
            vh= (ViewHolder) convertView.getTag();
        }
        switch (type){
                 case 0:
                 vh.t1.setText(mlist.get(position).getAuthor_name());
                 return  convertView;
                 case 1:
                 vh.t2.setText(mlist.get(position).getTitle());
                 ImageLoader.getInstance().displayImage(mlist.get(position).getThumbnail_pic_s02(),vh.i1);
                 ImageLoader.getInstance().displayImage(mlist.get(position).getThumbnail_pic_s03(),vh.i2);
                 ImageLoader.getInstance().displayImage(mlist.get(position).getThumbnail_pic_s(),vh.i3);
                 return convertView;
                 case 2:
                 vh.t3.setText(mlist.get(position).getAuthor_name());
                 ImageLoader.getInstance().displayImage(mlist.get(position).getThumbnail_pic_s02(),vh.i4);

                 return convertView;
        }
        return convertView;
    }
    class ViewHolder{
        TextView t1,t2,t3;
        ImageView i1,i2,i3,i4;
    }
}

图片加载

package com.beiw.tzk.app;

import android.app.Application;

import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

public class AppCont extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        ImageLoaderConfiguration build = new ImageLoaderConfiguration.Builder(this).build();
        ImageLoader.getInstance().init(build);
    }
}

BaseFragment

package com.beiw.tzk.base;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public abstract class BaseFragment  extends Fragment {
    public View mView;
    public Context mActivity;

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        this.mActivity=context;
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        //mView = inflater.in
        initView();
        return mView;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        initData();
    }
    public  abstract View initView();
    public  abstract void initData();
}

Bean类

封装的网络类和网路获取接口类

package com.beiw.tzk.homeWork;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class ConU {
    Context context;

    public ConU(Context context) {
        this.context = context;
    }

    public   boolean getNet(){
        //初始化网络状态
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        //网络类型
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
        return  networkInfo.isConnected();
    }
}

package com.beiw.tzk.homeWork;

import android.content.Context;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpC {
    public  static  String  getHttp(Context context,String url,String mRam){
        String messages = "";
        //String url = "http://result.eolinker.com/k2BaduF2a6caa275f395919a66ab1dfe4b584cc60685573?uri=" + uri + "";
        try {
            URL murl = new URL(url);
            HttpURLConnection connection = (HttpURLConnection) murl.openConnection();
            connection.setRequestMethod(mRam);
            connection.setConnectTimeout(5 * 1000);
            connection.setReadTimeout(5 * 1000);
            InputStream inputStream = connection.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));
            String len = "";
            while ((len = reader.readLine()) != null) {
                messages += len;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return messages;
    }
}

package com.beiw.tzk.homeWork;

import android.content.Context;
import android.os.AsyncTask;

public class MyTask<T> extends AsyncTask<T,T,String> {
    String  url;
    Context context;
    String mRam;
    private  TaskListeners taskListeners;

    public MyTask setTaskListener(TaskListeners taskListeners) {
        this.taskListeners = taskListeners;
        return  this;
    }

    public MyTask(String url, Context context, String mRam) {
        this.url = url;
        this.context = context;
        this.mRam = mRam;
    }
    @Override
    protected String doInBackground(T... ts) {
        return HttpC.getHttp(context,url,mRam);
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        if (s!=null){
            //
            taskListeners.result(s);
        }
    }
    //定义接口
    public  interface  TaskListeners{
        void result(String t);
    }
}

主页显示的视图

package com.beiw.tzk;

import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RadioGroup;

import com.beiw.tzk.base.BaseFragment;
import com.beiw.tzk.frag.Frag01;
import com.beiw.tzk.frag.Frag02;
import com.beiw.tzk.frag.Frag03;
import com.beiw.tzk.frag.Frag04;
import com.beiw.tzk.frag.Frag05;

import java.util.ArrayList;

public class ZyFragment extends Fragment {
        private ViewPager page;
        private RadioGroup radi;
        @Nullable
        @Override
        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.activity_zy_fragment,container,false);
            //找到组件
            page = view.findViewById(R.id.pager);
            radi = view.findViewById(R.id.radioGroup);
            //添加数据
            final ArrayList<Fragment> list = new ArrayList<>();
            Frag01 frag01 = new Frag01();
            Frag02 frag02 = new Frag02();
            Frag03 frag03 = new Frag03();
            Frag04 frag04 = new Frag04();
            Frag05 frag05 = new Frag05();
            list.add(frag01);
            list.add(frag02);
            list.add(frag03);
            list.add(frag04);
            list.add(frag05);

            //适配器
            page.setAdapter(new FragmentPagerAdapter(getActivity().getSupportFragmentManager()) {
                @Override
                public Fragment getItem(int i) {
                    return list.get(i);
                }

                @Override
                public int getCount() {
                    return list.size();
                }
            });
            //默认选中
            radi.check(radi.getChildAt(0).getId());
            //点击切换
            radi.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(RadioGroup group, int checkedId) {
                    switch (checkedId){
                        case R.id.radioButton0:
                            page.setCurrentItem(0);
                            break;
                        case R.id.radioButton1:
                            page.setCurrentItem(1);
                            break;
                        case R.id.radioButton2:
                            page.setCurrentItem(2);
                            break;
                        case R.id.radioButton3:
                            page.setCurrentItem(3);
                             break;
                        case R.id.radioButton4:
                            page.setCurrentItem(4);
                            break;
                    }
                }
            });
            //滑动监听
            page.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                @Override
                public void onPageScrolled(int i, float v, int i1) {

                }

                @Override
                public void onPageSelected(int i) {
                    radi.check(radi.getChildAt(i).getId());
                    page.setCurrentItem(i);
                }

                @Override
                public void onPageScrollStateChanged(int i) {

                }
            });
            return view;
        }
    }

<?xml version="1.0" encoding="utf-8"?>
<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"
    android:background="#fff"
    android:orientation="vertical"
    tools:context=".ZyFragment">
    <RadioGroup
        android:id="@+id/radioGroup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <RadioButton
            android:id="@+id/radioButton0"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:button="@null"
            android:gravity="center"
            android:textColor="@drawable/one"
            android:textSize="15sp"
            android:text="@string/app_yw" />
        <RadioButton
            android:id="@+id/radioButton1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:textColor="@drawable/two"
            android:layout_weight="1"
            android:button="@null"
            android:gravity="center"
            android:textSize="15sp"
            android:text="@string/app_sd" />
        <RadioButton
            android:id="@+id/radioButton2"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textColor="@drawable/three"
            android:button="@null"
            android:gravity="center"
            android:textSize="15sp"
            android:text="@string/app_kp" />
        <RadioButton
            android:id="@+id/radioButton3"
            android:layout_width="0dp"
            android:textColor="@drawable/four"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:button="@null"
            android:gravity="center"
            android:textSize="15sp"
            android:text="@string/app_xy" />
        <RadioButton
            android:id="@+id/radioButton4"
            android:layout_width="0dp"
            android:textColor="@drawable/five"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:button="@null"
            android:gravity="center"
            android:textSize="15sp"
            android:text="@string/app_dy" />

    </RadioGroup>
    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        ></android.support.v4.view.ViewPager>


</LinearLayout>

展示视图的界面

package com.beiw.tzk.frag;

import android.os.Bundle;
import android.support.annotation.NonNull;
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.Toast;

import com.beiw.tzk.R;
import com.beiw.tzk.adpter.MySetAdpter;
import com.beiw.tzk.bean.Bean;
import com.beiw.tzk.homeWork.ConU;
import com.beiw.tzk.homeWork.MyTask;
import com.beiw.tzk.xlistview.XListView;
import com.google.gson.Gson;

import java.util.List;

public class Frag02 extends Fragment {
    private MySetAdpter setAdpter;
    private View view;
    private XListView mls;
    String url="http://result.eolinker.com/k2BaduF2a6caa275f395919a66ab1dfe4b584cc60685573?uri=tt";
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.frag02,container,false);
         mls = view.findViewById(R.id.mls);

         new ConU(getActivity()).getNet();
        if (new ConU(getActivity()).getNet()){
             Toast.makeText(getActivity(),"网络已连接",Toast.LENGTH_LONG).show();
             init();
         }else{
             Toast.makeText(getActivity(),"网络不可用",Toast.LENGTH_LONG).show();
         }

        return view;
    }

    private void init() {
        new MyTask<String>(url,getActivity(),"GET").setTaskListener(new MyTask.TaskListeners() {
            @Override
            public void result(String t) {
                if (t!=null){
                    Gson gson = new Gson();
                    Bean bean = gson.fromJson(t, Bean.class);
                    final List<Bean.ResultBean.DataBean> data = bean.getResult().getData();
                    setAdpter = new MySetAdpter(getActivity(), data);
                    mls.setAdapter(setAdpter);
                    }
                }


        }).execute();
    }

}

XListView布局

<?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:background="#0f0"
    >
   <com.beiw.tzk.xlistview.XListView
       android:id="@+id/mls"
       android:layout_width="match_parent"
       android:layout_height="match_parent"></com.beiw.tzk.xlistview.XListView>
</LinearLayout>

<?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:layout_width="match_parent"
       android:layout_height="match_parent"
       android:id="@+id/t1"
       />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >
   <TextView
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:textSize="18dp"
       android:id="@+id/t2"
       android:text="字体"
       />

   <ImageView
       android:id="@+id/i1"
       android:layout_marginLeft="20dp"
       android:layout_width="80dp"
       android:layout_height="80dp"
       android:layout_alignParentStart="true"
       android:layout_alignParentTop="true"
       android:layout_marginStart="16dp"
       android:layout_marginTop="54dp"
       app:srcCompat="@mipmap/ic_launcher" />

   <ImageView
       android:id="@+id/i2"
       android:layout_width="80dp"
       android:layout_height="80dp"
       android:layout_marginLeft="20dp"
       android:layout_alignParentStart="true"
       android:layout_alignParentTop="true"
       android:layout_marginStart="133dp"
       android:layout_marginTop="56dp"
       app:srcCompat="@mipmap/ic_launcher" />

   <ImageView
       android:id="@+id/i3"
       android:layout_width="80dp"
       android:layout_marginLeft="20dp"
       android:layout_height="80dp"
       android:layout_alignParentTop="true"
       android:layout_alignParentEnd="true"
       android:layout_marginTop="56dp"
       android:layout_marginEnd="72dp"
       app:srcCompat="@mipmap/ic_launcher" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >
   <TextView
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:textSize="25dp"
       android:id="@+id/t3"
       android:text="字体"
       />

   <ImageView
       android:id="@+id/i4"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:layout_alignParentStart="true"
       android:layout_alignParentTop="true"
       android:layout_marginStart="16dp"
       android:layout_marginTop="54dp"
       app:srcCompat="@mipmap/ic_launcher" />


</RelativeLayout>