Android——手机内部文件存储（作业）

作业：把用户的注册信息存储到文件里，登录成功后读出并显示出来

activity_practice2的layout文件：

<?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.testapp3.PractiseActivity2"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <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/et_username"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密码："/>
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/et_password"
            android:inputType="textPassword"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="登陆"
        android:onClick="bt_dl_onClick"
        android:layout_weight="1"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="注册"
            android:onClick="bt_zc_onClick"
            android:layout_weight="1"/>
    </LinearLayout>

    <!--<Button-->
        <!--android:layout_width="match_parent"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:text="fdasf"-->
        <!--android:onClick="bt_onClick"-->
        <!--android:id="@+id/bt_1"/>-->
</LinearLayout>

activity_practice2_2的layout文件： 

<?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.hanqi.testapp3.PractiseActivity2_2">

        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="用户名称"
            android:id="@+id/et_username_1"/>
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="登陆密码"
            android:id="@+id/et_password_1"
            android:layout_below="@id/et_username_1"
            android:inputType="textPassword"/>
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="个性签名"
            android:id="@+id/et_gxqm"
            android:layout_below="@id/et_password_1"/>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true">
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="确定"
                android:layout_weight="1"
                android:onClick="bt_qd_onClick"/>
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="取消"
                android:layout_weight="1"
                android:onClick="bt_qx_onClick"/>
        </LinearLayout>
    <!--<Button-->
        <!--android:layout_width="match_parent"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:text="fdasf"-->
        <!--android:onClick="bt_onClick"-->
        <!--android:id="@+id/bt_1"-->
        <!--android:layout_below="@+id/et_gxqm"/>-->
</RelativeLayout>

activity_practice2_3的layout文件：

<?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.hanqi.testapp3.PractiseActivity2_3">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tv_username"
        android:textSize="30dp"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tv_gxqm"
        android:layout_below="@id/tv_username"
        android:textSize="30dp"/>
</RelativeLayout>

PractiseActivity2的java类：

package com.hanqi.testapp3;

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

import java.io.FileInputStream;

public class PractiseActivity2 extends AppCompatActivity {

    EditText et_username;
    EditText et_password;

//    Button bt_1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_practise2);
        et_username = (EditText)findViewById(R.id.et_username);
        et_password = (EditText)findViewById(R.id.et_password);
        //bt_1 = (Button)findViewById(R.id.bt_1);
    }
    public void bt_zc_onClick(View v)
    {
        Intent intent = new Intent(this,PractiseActivity2_2.class);
        startActivity(intent);
    }

    public void bt_dl_onClick(View v)
    {
        String str1 = "";
        String str2 = "";
        String str3 = "";
        String uc = et_username.getText().toString();
        String pw = et_password.getText().toString();

        try {
            FileInputStream fis = openFileInput("practise2-1.txt");
            byte[] b = new byte[1024];
            int i;

            while ((i=fis.read(b))>0)
            {
                String str = new String(b,0,i);
                str1 += str;
            }
            fis.close();

            FileInputStream fis2 = openFileInput("practise2-2.txt");
            byte[] b2 = new byte[1024];
            int i2 = 0;
            while ((i2=fis2.read(b2))>0)
            {
                String str = new String(b2,0,i2);
                str2 += str;
            }
            fis2.close();

            FileInputStream fis3 = openFileInput("practise2-3.txt");
            byte[] b3 = new byte[1024];
            int i3 = 0;
            while ((i3=fis3.read(b3))>0)
            {
                String str = new String(b3,0,i3);
                str3 += str;
            }
            fis3.close();
        }
       catch (Exception e)
       {

       }
        if (uc.trim().length()==0||pw.trim().length()==0)
        {
            Toast.makeText(PractiseActivity2.this, "用户名和密码不能为空", Toast.LENGTH_SHORT).show();
            return;
        }
        if (str1 ==null||(str1!=null&&!str1.equals(uc)))
        {
            Toast.makeText(PractiseActivity2.this, "用户未注册", Toast.LENGTH_SHORT).show();
            return;
        }
        if (!str2.equals(pw))
        {
            Toast.makeText(PractiseActivity2.this, "密码错误", Toast.LENGTH_SHORT).show();
            return;
        }
        else
        {
            Toast.makeText(PractiseActivity2.this, "用户验证成功", Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(this,PractiseActivity2_3.class);
            startActivity(intent);
            finish();
        }
    }
//    public void bt_onClick(View v)
//    {
//        try {
//            FileInputStream fis = openFileInput("practise2-1.txt");
//            byte[] b = new byte[1024];
//            int i;
//
//            while ((i=fis.read(b))>0)
//            {
//                String str = new String(b,0,i);
//                str1 += str;
//            }
//
//            fis.close();
//        }
//        catch (Exception e)
//        {
//
//        }
//        bt_1.setText(str1);
//    }
}

PractiseActivity2_2的java类：

package com.hanqi.testapp3;

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

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

public class PractiseActivity2_2 extends AppCompatActivity {

    EditText et_username_1;
    EditText et_password_1;
    EditText et_gxqm;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_practise2_2);
        et_username_1 = (EditText)findViewById(R.id.et_username_1);
        et_password_1 = (EditText)findViewById(R.id.et_password_1);
        et_gxqm = (EditText)findViewById(R.id.et_gxqm);
    }
    public void bt_qd_onClick(View v)
    {
        String username = et_username_1.getText().toString();
        if (username ==null||username.trim().length()==0)
        {
            Toast.makeText(PractiseActivity2_2.this, "请填写用户名", Toast.LENGTH_SHORT).show();
            return;
        }
        String password = et_password_1.getText().toString();
        if (password ==null||password.trim().length()==0)
        {
            Toast.makeText(PractiseActivity2_2.this, "请填写密码", Toast.LENGTH_SHORT).show();
            return;
        }
        String gxqm = et_gxqm.getText().toString();
        if (gxqm ==null||gxqm.trim().length()==0)
        {
            Toast.makeText(PractiseActivity2_2.this, "个性签名为必填内容", Toast.LENGTH_SHORT).show();
            return;
        }
        try {
            FileOutputStream fos = openFileOutput("practise2-1.txt",MODE_PRIVATE);
            PrintStream ps = new PrintStream(fos);
            ps.print(username);
            FileOutputStream fos2 = openFileOutput("practise2-2.txt",MODE_PRIVATE);
            PrintStream ps2 = new PrintStream(fos2);
            ps2.print(password);
            FileOutputStream fos3 = openFileOutput("practise2-3.txt",MODE_PRIVATE);
            PrintStream ps3 = new PrintStream(fos3);
            ps3.print(gxqm);
            ps.close();
            ps2.close();
            ps3.close();
            fos.close();
            Toast.makeText(PractiseActivity2_2.this, "保存成功", Toast.LENGTH_SHORT).show();
        }
        catch (Exception e)
        {

        }
        Intent intent = new Intent(this,PractiseActivity2.class);
        startActivity(intent);
        finish();
    }
    public void bt_qx_onClick(View v)
    {
        setResult(RESULT_CANCELED, null);
        finish();
    }

}

PractiseActivity2_3的java类：

package com.hanqi.testapp3;

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

import java.io.FileInputStream;

public class PractiseActivity2_3 extends AppCompatActivity {

    TextView tv_username;
    TextView tv_gxqm;

    String str1 = "";
    String str3 = "";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_practise2_3);
        tv_username = (TextView)findViewById(R.id.tv_username);
        tv_gxqm = (TextView)findViewById(R.id.tv_gxqm);

        try {
            FileInputStream fis = openFileInput("practise2-1.txt");
            byte[] b = new byte[1024];
            int i;

            while ((i=fis.read(b))>0)
            {
                String str = new String(b,0,i);
                str1 += str;
            }

            fis.close();

            FileInputStream fis3 = openFileInput("practise2-3.txt");
            byte[] b3 = new byte[1024];
            int i3 = 0;
            while ((i3=fis3.read(b3))>0)
            {
                String str = new String(b3,0,i3);
                str3 += str;
            }
            fis3.close();
        }
        catch (Exception e)
        {

        }
        tv_username.setText("用户名是：" + str1);
        tv_gxqm.setText("个性签名是："+str3);
    }
}

效果为：