Android——用对话框做登陆界面(自定义对话框AlertDialog，多线程，进度条ProgressDialog，ListView，GridView，SharedPreferences存，读数据，存取文本，assets文件)

效果：

1.点击图标进入页面二

2.页面2图片暂停显示5秒进入页面三

3.点击页面三登陆按钮，打开登陆对话框，输入密码进入页面四

点击下载按钮，显示水平进度条

点击保存和获取用户名和密码 进入页面六 操作SharedPreferences

点击文本和文件 进入页面八

4.页面四是一个用BaseAdapt适配器加载的ListView,点击相册行时，跳转至页面五

点击地图时，跳转值页面七，gridview视图（图+字）

5.页面五是一个用GridView建的网格视图（图）

6.页面六 操作SharedPreferences

7.页面八，操作文本和文件的保存和获取

MainActivity.java

package com.example.chenshuai.test404;

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

public class MainActivity extends AppCompatActivity {

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

    public void onclick(View view)
    {
        Intent intent = new Intent(this,Activity1.class);
        startActivity(intent);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.chenshuai.test404.MainActivity">

   <ImageButton
       android:layout_width="90dp"
       android:layout_height="90dp"
       android:src="@drawable/logo"
       android:onClick="onclick"/>
</RelativeLayout>

Activity1.java

package com.example.chenshuai.test404;

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

import java.util.Timer;
import java.util.TimerTask;

/**
 * Created by chenshuai on 2016/4/3.
 */
public class Activity1 extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity1_layout);

        //图片暂停5秒后显示
        final Intent it = new Intent(this, Activity2.class); //你要转向的Activity
        Timer timer = new Timer();
        TimerTask task = new TimerTask() {
            @Override
            public void run() {
                startActivity(it); //执行
            }
        };
        timer.schedule(task, 1000 * 5); //5秒后

    }
}

activity1_layout.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">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/denglu"/>

</LinearLayout>

Activity2.java

package com.example.chenshuai.test404;

import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

/**
 * Created by chenshuai on 2016/4/3.
 */
public class Activity2 extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2_layout);

    }

    public void onclik1(View view)
    {

        //获取加载器
        LayoutInflater layoutInflater = getLayoutInflater();
        //加载layout文件
        View vi_1 = layoutInflater.inflate(R.layout.login_layout,null);
        //添加按钮
        new AlertDialog.Builder(this)
                .setView(vi_1)
                .setNegativeButton("取消", null)
                .setPositiveButton("登陆", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        AlertDialog al = (AlertDialog) dialog;

                        EditText pwd = (EditText) al.findViewById(R.id.pwd);

                        String str = pwd.getText().toString();

                        if (str.equals("123")) {
                            Intent intent = new Intent(Activity2.this, Activity3.class);
                            startActivity(intent);
                        } else {
                            Toast.makeText(Activity2.this, "密码错误！", Toast.LENGTH_SHORT).show();
                        }

                    }
                })
                .show();
    }
    public void onclick2(View v)
    {
        final ProgressDialog pd = new ProgressDialog(this);
        pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

        pd.setMessage("下载进度");
        pd.show();

        //创建thread实例  重写run方法  启动多线程
        new Thread()
        {
            @Override
            public void run() {
                super.run();
                for (int i = 0;i<=pd.getMax();i++)
                {
                    try {
                        Thread.sleep(100);
                    }catch (Exception e)
                    {}
                    pd.setProgress(i);
                }
                pd.dismiss();
            }
        }.start();
    }

    public void onclick3(View view)
    {

        Intent intent = new Intent(this,Activity5.class);
        startActivity(intent);
    }
    public void onclick4(View view)
    {
        Intent intent = new Intent(this,Activity7.class);
        startActivity(intent);
    }

}

activity2_layout.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"
    android:orientation="vertical">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:background="@drawable/anniu1"
        android:text="点击登陆"
        android:textSize="20dp"
        android:onClick="onclik1"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/anniu2"
        android:text="点击下载文件"
        android:textSize="20dp"
        android:onClick="onclick2"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="点击保存用户名和密码 key/value"
        android:textSize="20dp"
        android:background="@drawable/anniu13"
        android:onClick="onclick3"/>
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="点击文本和文件"
        android:textSize="20dp"
        android:background="@drawable/anniu1"
        android:onClick="onclick4"/>

</LinearLayout>

login_layout.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"
    android:orientation="vertical">

    <ImageView
        android:layout_width="90dp"
        android:layout_height="90dp"
        android:src="@drawable/touxiang"
        android:layout_marginTop="100dp"
        android:layout_gravity="center_horizontal"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="15275969278"
        android:textSize="20dp"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="10dp"
        />
    <EditText
        android:layout_width="350dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:hint="请填写密码"
       android:inputType="textPassword"
        android:drawableLeft="@drawable/suo1"
        android:layout_marginTop="20dp"
        android:id="@+id/pwd"
     />

</LinearLayout>

Activity3.java

package com.example.chenshuai.test404;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

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

/**
 * Created by chenshuai on 2016/4/4.
 */

public class Activity3 extends Activity {
    List<Biaozhi> bz;

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

        ListView base_1 = (ListView)findViewById(R.id.base_1);

        bz = new ArrayList<Biaozhi>();
        bz.add(new Biaozhi(R.drawable.dazhong,"大众点评"));
        bz.add(new Biaozhi(R.drawable.gallery,"相册"));
        bz.add(new Biaozhi(R.drawable.maps,"地图"));
        bz.add(new Biaozhi(R.drawable.mm,"聊天"));
        bz.add(new Biaozhi(R.drawable.netease,"网易新闻"));
        bz.add(new Biaozhi(R.drawable.qq,"QQ"));
        bz.add(new Biaozhi(R.drawable.settings,"设置"));
        bz.add(new Biaozhi(R.drawable.sinaweibo,"新浪微博"));
        bz.add(new Biaozhi(R.drawable.stormsmart,"暴风影音"));
        bz.add(new Biaozhi(R.drawable.taobao,"淘宝"));
        bz.add(new Biaozhi(R.drawable.videoplayer,"视频"));

        base_1.setAdapter(new mybaseadapt());

        base_1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                if (position == 1)
                {
                    Intent in = new Intent(Activity3.this,Activity4.class);

                    startActivity(in);
                }
                if (position ==2)
                {
                    Intent in = new Intent(Activity3.this,Activity6.class);

                    startActivity(in);
                }
            }
        });
    }

    //抽象类 要继承并实现抽象方法后才能使用
    class mybaseadapt extends BaseAdapter{
        @Override
        public int getCount() {
            return bz.size();
        }

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

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

        //通过getView来实现Listview
        //给视图适配数据返回view视图
        //position 数据的下标（第几个视图）
        //convertView 可重复使用的视图
        //parent 父视图
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            //如果convertView为null，就加载layout文件
            if (convertView == null)
            {
                //1.获取layout文件  用加载器
                LayoutInflater inflater = getLayoutInflater();

                convertView = inflater.inflate(R.layout.activity3_layout,null);

            }

            //2.把数据放入layout文件中  数据和layout文件的视图组件进行绑定
            //（1）从数据源里根据position获取数据
            Biaozhi biaozhi = bz.get(position);

            //（2）获取layout文件的视图组件
            ImageView iv_1 = (ImageView)convertView.findViewById(R.id.iv_1);
            TextView tv_1 = (TextView)convertView.findViewById(R.id.tv_1);

            //(3)绑定  数据适配
            iv_1.setImageResource(biaozhi.getImage());
            tv_1.setText(biaozhi.getName());

            //3.返回视图
            return convertView;
        }
    }
}

base_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/base_1">

</ListView>

activity3_layout.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="wrap_content"
    android:layout_marginTop="20dp">

    <ImageView
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:src="@drawable/logo"
        android:id="@+id/iv_1"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_gravity="center_vertical"
        android:paddingLeft="20dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="微信"
            android:textSize="20dp"
            android:id="@+id/tv_1"/>

    </LinearLayout>

</LinearLayout>

Activity4.java

package com.example.chenshuai.test404;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class Activity4 extends AppCompatActivity {

    int img[] = {R.drawable.dazhong,R.drawable.gallery,R.drawable.maps,R.drawable.mm,
                 R.drawable.qq,R.drawable.settings,R.drawable.sinaweibo,R.drawable.netease,
                 R.drawable.stormsmart,R.drawable.torchactivity,R.drawable.videoplayer};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_4);

        GridView grv_1 = (GridView)findViewById(R.id.grv_1);

        grv_1.setAdapter(new mygridview());
    }

    class mygridview extends BaseAdapter{

        @Override
        public int getCount() {
            return img.length;
        }

        @Override
        public Object getItem(int position) {
            return img[position];
        }

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

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

            //先取数据
            int imageid = img[position];

            //直接构造视图
            ImageView imageView =null;

            if (convertView == null)
            {
                imageView = new ImageView(Activity4.this);

                imageView.setLayoutParams(new GridView.LayoutParams(200,200));
            }
            else
            {
                imageView=(ImageView)convertView;
            }
            //给视图绑定数据
            imageView.setImageResource(imageid);

            return imageView;
        }
    }
}

activity_4.xml

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:numColumns="4"
    android:verticalSpacing="10dp"
    android:gravity="center"
    android:stretchMode="columnWidth"
    android:id="@+id/grv_1"
    >

</GridView>

Activity5.java

package com.example.chenshuai.test404;

import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class Activity5 extends AppCompatActivity {

    EditText user;
    EditText pwd;
    SharedPreferences sp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_5);

         user = (EditText)findViewById(R.id.user);
         pwd = (EditText)findViewById(R.id.pwd);

        //1.获取sp的实例
        sp = getSharedPreferences("mydata",MODE_PRIVATE);
    }

    //保存
    public void baocunclick(View view)
    {
        //1.获取数据
        String username = user.getText().toString();
        String password = pwd.getText().toString();

        //判断不为空
        if (username.length() == 0 || password.length() ==0)
        {

            Toast.makeText(Activity5.this, "用户名和密码不为空", Toast.LENGTH_SHORT).show();
        }
        else
        {
            //2.用Editor存储数据
            //获取Editor
            SharedPreferences.Editor editor_1 = sp.edit();

            //3.往编辑器里放数据(从上面获取的数据)
            editor_1.putString(username,password);

            //4.提交保存
            boolean b = editor_1.commit();

            if (b)
            {
                Toast.makeText(Activity5.this, "保存成功", Toast.LENGTH_SHORT).show();
            }
            else
            {
                Toast.makeText(Activity5.this, "保存失败", Toast.LENGTH_SHORT).show();
            }

        }

    }

    //获取
    public void huoquclick(View view)
    {
        //1.获取要读的key；
        String key = user.getText().toString();

        //2.将通过用户名读取的密码放入第二个Edittext
        pwd.setText(sp.getString(key,"没有发现用户名"));
    }
}

activity_5.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="com.example.chenshuai.test404.Activity5"
    android:orientation="vertical">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户名："
        android:id="@+id/user"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="密码："
        android:id="@+id/pwd"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="保存"
            android:id="@+id/baocun"
            android:onClick="baocunclick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="获取"
            android:id="@+id/huoqu"
            android:onClick="huoquclick"/>
    </LinearLayout>

</LinearLayout>

Activity6.java

package com.example.chenshuai.test404;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;

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

public class Activity6 extends AppCompatActivity {

    List<Biaozhi> bz;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_6);

        GridView gv_1 = (GridView)findViewById(R.id.gv_1);

        bz = new ArrayList<Biaozhi>();
        bz.add(new Biaozhi(R.drawable.dazhong,"大众点评"));
        bz.add(new Biaozhi(R.drawable.gallery,"相册"));
        bz.add(new Biaozhi(R.drawable.maps,"地图"));
        bz.add(new Biaozhi(R.drawable.mm,"聊天"));
        bz.add(new Biaozhi(R.drawable.netease,"网易新闻"));
        bz.add(new Biaozhi(R.drawable.qq,"QQ"));
        bz.add(new Biaozhi(R.drawable.settings,"设置"));
        bz.add(new Biaozhi(R.drawable.sinaweibo, "新浪微博"));
        bz.add(new Biaozhi(R.drawable.stormsmart, "暴风影音"));
        bz.add(new Biaozhi(R.drawable.taobao,"淘宝"));
        bz.add(new Biaozhi(R.drawable.videoplayer,"视频"));

        gv_1.setAdapter(new grid_baseadapter());
    }

    //抽象类 要继承并实现抽象方法后才能使用
    class grid_baseadapter extends BaseAdapter
    {
        @Override
        public int getCount() {
            return bz.size();
        }

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

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

        //通过getView来实现Listview
        //给视图适配数据返回view视图
        //position 数据的下标（第几个视图）
        //convertView 可重复使用的视图
        //parent 父视图
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            //如果convertView为null，就加载layout文件
            if (convertView == null)
            {
                //1.获取layout文件  用加载器
                LayoutInflater inflater = getLayoutInflater();

                convertView = inflater.inflate(R.layout.layout_6_1,null);

            }
            //2.把数据放入layout文件中  数据和layout文件的视图组件进行绑定
            //（1）从数据源里根据position获取数据
            Biaozhi biaozhi = bz.get(position);

            //（2）获取layout文件的视图组件
            ImageView iv_2 = (ImageView)convertView.findViewById(R.id.iv_2);
            TextView tv_2 = (TextView)convertView.findViewById(R.id.tv_2);

            //(3)绑定  数据适配
            iv_2.setImageResource(biaozhi.getImage());
            tv_2.setText(biaozhi.getName());

            //3.返回视图
            return convertView;
        }
    }
}

Biaozhi.java

package com.example.chenshuai.test404;

/**
 * Created by chenshuai on 2016/4/7.
 */
public class Biaozhi {

    private int image;

    private String name;

    public int getImage() {
        return image;
    }

    public String getName() {
        return name;
    }

    public void setImage(int image) {
        this.image = image;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Biaozhi(int image, String name) {
        this.image = image;
        this.name = name;
    }

    public Biaozhi()
    {

    }

    @Override
    public String toString() {
        return "Biaozhi{" +
                "image=" + image +
                ", name='" + name + '\'' +
                '}';
    }
}

Activity_6.xml

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/gv_1"
    android:numColumns="4"
    android:verticalSpacing="10dp"
    android:stretchMode="columnWidth"
   >
</GridView>

Activity_6_1.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"
    android:orientation="vertical">

    <ImageView
        android:layout_width="120dp"
        android:layout_height="120dp"
        android:src="@drawable/dazhong"
        android:id="@+id/iv_2"/>
    <TextView
        android:layout_width="120dp"
        android:layout_height="wrap_content"
        android:text="大众点评"
        android:textSize="20dp"
        android:gravity="center"
        android:id="@+id/tv_2"/>

</LinearLayout>

Activity7.java

package com.example.chenshuai.test404;

import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.PrintStream;

public class Activity7 extends AppCompatActivity {
    EditText et_1;
    EditText et_2;

    ImageView iv_3;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_7);

        et_1 = (EditText)findViewById(R.id.et_1);
        et_2 = (EditText)findViewById(R.id.et_2);

        iv_3 = (ImageView)findViewById(R.id.iv_3);
    }

    final String FILENAME = "text.txt";
    public void baocunwenben_onclick(View view)
    {

        //1.获取要存储的内容
        String content = et_1.getText().toString();

        //2.获取输出流 以数据为基准 从手机存储往文件走为输出流
        try {
            //追加模式
            FileOutputStream fos = openFileOutput(FILENAME,MODE_APPEND);

            //3.构造打印流 PrintStream
            PrintStream ps = new PrintStream(fos);

            //4.写入内容（换行）
            ps.println(content);

            //5.关闭
            ps.close();
            fos.close();

            Toast.makeText(Activity7.this, "保存成功", Toast.LENGTH_SHORT).show();

        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(Activity7.this, "保存失败", Toast.LENGTH_SHORT).show();
        }

    }
    //获取
    public void huoquwenben_onclick(View view)
    {

        //1.获取输入流  从文件到手机存储
        try {
            FileInputStream fis = openFileInput(FILENAME);

            //2.用数组方法读取
            //定义读取的数组

            byte[] b = new byte[1024];
            //3.读出的数据的长度
            int i = 0;

            StringBuilder sbr = new StringBuilder();

            //fis.read(b)返回长度
            while ((i = fis.read(b))>0)
            {
                //在这里需要字符串，转为字符串
                sbr.append(new String(b,0,i));
            }

            fis.close();

            et_2.setText(sbr);

            Toast.makeText(Activity7.this, "读取成功", Toast.LENGTH_SHORT).show();

        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(Activity7.this, "读取失败", Toast.LENGTH_SHORT).show();
        }
    }
    //操作assets内的文件
    public void baocuntupianwj_onclick(View view)
    {
        //1.获取AssetManager
        AssetManager assetManager = getAssets();

        //2.打开文件  返回输入流 把文件读到内存里
        try {
            InputStream is = assetManager.open("zixingche.jpg");

            //3.获取输出流
            FileOutputStream fos = openFileOutput("zixingche2.jpg",MODE_PRIVATE);

            //4.边读边写
            byte[] b =new byte[1024];

            int i = 0;

            while((i = is.read(b))>0)
            {
                fos.write(b, 0, i);
            }

            fos.close();
            is.close();

            Toast.makeText(Activity7.this, "保存成功", Toast.LENGTH_SHORT).show();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //读取文件 从手机内部存储读图片文件
    public void huoqutupianwj_onclick(View view)
    {
        //改变ImageView的图片来源，指向手机存储空间

        //1.获取文件存储的绝对路径
        String filepath  = getFilesDir().getAbsolutePath();

        //2.组合完整路径
        filepath += "/zixingche2.jpg";

        Toast.makeText(Activity7.this, "path= "+filepath, Toast.LENGTH_SHORT).show();

        //3.生成位图实例
        Bitmap bm = BitmapFactory.decodeFile(filepath);

        //4.改变ImageView的图片来源 显示图片
        iv_3.setImageBitmap(bm);
    }
}

Activity_7.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"
    android:orientation="vertical"
    >
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入要保存的文本"
        android:id="@+id/et_1"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="显示保存的文本"
        android:id="@+id/et_2"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:text="点击保存文本"
            android:layout_weight="1"
            android:onClick="baocunwenben_onclick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:text="点击获取文本"
            android:layout_weight="1"
            android:onClick="huoquwenben_onclick"/>

    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:text="点击保存图片文件"
            android:layout_weight="1"
            android:onClick="baocuntupianwj_onclick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:text="点击获取图片文件"
            android:layout_weight="1"
            android:onClick="huoqutupianwj_onclick"/>

    </LinearLayout>
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/touxiang"
        android:layout_gravity="center"
        android:id="@+id/iv_3"
        />

</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.chenshuai.test404">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity1">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity2">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity3">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity4">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity5">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity6">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Activity7">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
    </application>

</manifest>

AndroidManifest.xml