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>