Files存储练习

package com.hanqi.myapplication;

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

import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintStream;

public class Main2Activity extends AppCompatActivity {
    EditText user_name;
    EditText user_password;
    Button bt_1;
    Button bt_2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        user_name=(EditText)findViewById(R.id.user_name);
        user_password=(EditText)findViewById(R.id.user_password);
        bt_1=(Button)findViewById(R.id.bt_1);
        bt_1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String input_username=user_name.getText().toString();
                String input_password=user_password.getText().toString();
                if (input_username.trim().length()==0||input_password.trim().length()==0)
                {
                    Toast.makeText(Main2Activity.this, "用户名或密码不能为空", Toast.LENGTH_SHORT).show();
                }else
                {
                    Intent intent=new Intent(Main2Activity.this,Main22Activity.class);
                    startActivity(intent);
                    try
                    {
                        File file=getFilesDir();
                        String path=file.getAbsolutePath();
                        FileOutputStream fos=openFileOutput("test.txt", MODE_APPEND);
                        PrintStream ps=new PrintStream(fos);
                        ps.print(input_username);
                        ps.close();
                        fos.close();
                        FileOutputStream fos1=openFileOutput("tes.txt", MODE_APPEND);
                        PrintStream ps1=new PrintStream(fos1);
                        ps1.print(input_password);
                        ps1.close();
                        fos1.close();
                        Toast.makeText(Main2Activity.this, "保存成功", Toast.LENGTH_SHORT).show();
                    }catch (Exception e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        });
    }
}

package com.hanqi.myapplication;

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

import java.io.FileInputStream;

public class Main22Activity extends AppCompatActivity {
    EditText file_name;
    EditText file_password;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main22);
        file_name=(EditText)findViewById(R.id.file_name);
        file_password=(EditText)findViewById(R.id.file_password);
        try
        {
            FileInputStream fis =openFileInput("test.txt");
            byte[] bytes =new byte[1024];
            int i=0;
            String str1 = "";
            while ((i=fis.read(bytes))>0)
            {
                String str = new String(bytes,0,i);
                str1+=str;
            }
            fis.close();
            file_name.setText(str1);

            int ii=0; FileInputStream fis1 =openFileInput("tes.txt");
            byte[] bytes1 =new byte[1024];
            String str2 = "";
            while ((ii=fis1.read(bytes1))>0)
            {
                String str = new String(bytes1,0,ii);
                str2+=str;
            }
            fis1.close();
            file_password.setText(str2);
        }catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

<?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"
    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.hanqi.myapplication.Main2Activity"
    android:orientation="vertical">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/user_name"
        android:hint="用户名"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/user_password"
        android:hint="用户密码"/>

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/bt_1"
            android:text="登陆"
            />

</LinearLayout>

<?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"
    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.hanqi.myapplication.Main22Activity"
    android:orientation="vertical">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用户名："/>
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/file_name"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用户密码："/>
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/file_password"/>
    </LinearLayout>

</LinearLayout>