第十一周作业

1. 用内部存储实现

import java.io.BufferedReader;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;

import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.content.SharedPreferences;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void click1(View view){
        EditText editText=findViewById(R.id.et1);

        String filename="data.txt";
        String content=editText.getText().toString();
        FileOutputStream fos=null;
        try {
            fos=openFileOutput(filename, MODE_PRIVATE);
            fos.write(content.getBytes());
        } catch (Exception e) {

            e.printStackTrace();
        }finally{
            if(fos!=null)
                try {
                    fos.close();
                } catch (IOException e) {

                    e.printStackTrace();
                }
        }
        Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show();
    }

    public void click2(View view){
        EditText editText=findViewById(R.id.et2);
        String content="";
        FileInputStream fis=null;
        try {
            fis=openFileInput("data.txt");
            byte[] buffer=new byte[fis.available()];
            fis.read(buffer);
            content=new String(buffer);

        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            if(fis!=null)
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
       editText.setText(content);

    }

　　

<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=".MainActivity"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/et1"
        android:layout_width="280dp"
        android:layout_height="wrap_content"
        android:hint="输入你想写入的内容"
        android:textSize="70px" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="click1"
        android:text="写入"
        android:textSize="35dp"/>

    <EditText
        android:id="@+id/et2"
        android:layout_width="280dp"
        android:layout_height="wrap_content"
        android:hint="显示读取的内容"
        android:textSize="70px"
        />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="click2"
        android:text="读取"
        android:textSize="35dp"/>

</LinearLayout>

　　

 

 

2.使用sharedpreference实现记住密码功能

import java.io.File;
import java.util.Map;
import android.os.Bundle;
import android.app.Activity;
import android.content.DialogInterface.OnClickListener;
import android.content.SharedPreferences.Editor;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.Toast;

import androidx.annotation.CheckResult;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity implements android.view.View.OnClickListener{

    private EditText et_account;
    private EditText et_password;
    private Button btn_login;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        Map<String, String> userInfo=FileSaveQQ.getUserInfo(this);
        if(userInfo!=null){
            et_account.setText(userInfo.get("account"));
            et_password.setText(userInfo.get("password"));
        }
    }
    private void initView() {
        // TODO Auto-generated method stub
        et_account=(EditText)findViewById(R.id.et_account);
        et_password=(EditText)findViewById(R.id.et_password);
        btn_login=(Button)findViewById(R.id.btn_login);
        btn_login.setOnClickListener(this);
        CheckBox cb1=findViewById(R.id.cb_1);
        cb1.setOnClickListener(this);
        CheckBox cb2=findViewById(R.id.cb_2);
        cb2.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch(v.getId()){
            case R.id.btn_login:
                String account=et_account.getText().toString().trim();
                String password=et_password.getText().toString();
                if(TextUtils.isEmpty(account)){
                    Toast.makeText(this, "请输入账号", Toast.LENGTH_SHORT).show();
                    return;
                }
                if(TextUtils.isEmpty(password)){
                    Toast.makeText(this, "请输入密码", Toast.LENGTH_SHORT).show();
                    return;
                }
                Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();

        }

    }

    public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
        switch (compoundButton.getId()){
            case R.id.cb_1 :
                String account=et_account.getText().toString().trim();
                String password=et_password.getText().toString();
                boolean isSaveSuccess=FileSaveQQ.saveUserInfo(this, account, password);
                if(isSaveSuccess&&b){
                    Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show();
                }else{
                    Toast.makeText(this, "保存失败", Toast.LENGTH_SHORT).show();
                    et_account.setText(null);
                    et_password.setText(null);
                }

                break;
            case R.id.cb_2: account=et_account.getText().toString().trim();
                password=et_password.getText().toString();
                if(TextUtils.isEmpty(account)){
                    Toast.makeText(this, "请输入账号", Toast.LENGTH_SHORT).show();
                    return;
                }
                if(TextUtils.isEmpty(password)){
                    Toast.makeText(this, "请输入密码", Toast.LENGTH_SHORT).show();
                    return;
                }
                if(b)
                    Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();
                else{
                    Toast.makeText(this, "请登录", Toast.LENGTH_SHORT).show();
                }

        }
    }
}

　　

import android.content.Context;
import android.content.SharedPreferences;

import java.util.HashMap;
import java.util.Map;

 class FileSaveQQ{
    private static String password;

    public static boolean saveUserInfo(Context context, String account, String password) {
        FileSaveQQ.password = password;
        SharedPreferences sp=context.getSharedPreferences("data",Context.MODE_PRIVATE);
        SharedPreferences.Editor edit=sp.edit();
        edit.putString("userName", account);
        edit.putString("pwd",password);
        edit.commit();
        return true;
    }
    public  static Map<String,String > getUserInfo(Context context){
        SharedPreferences sp=context.getSharedPreferences("data", Context.MODE_PRIVATE);
        String account=sp.getString("useName",null);
        String password=sp.getString("pwd",null);
        Map<String,String > userMap=new HashMap<String, String>();
        userMap.put("account",account);
        userMap.put("password",password);
        return userMap;

    }
}

　　

<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:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:orientation="horizontal"
        >
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:text="账号"
            android:textColor="#000"
            android:textSize="20sp"
            />
        <EditText
            android:id="@+id/et_account"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:hint="请输入用户名"
            android:background="@null"
            android:padding="10dp"
            />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:orientation="horizontal"
        >
        <TextView
            android:id="@+id/tv_password"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="10dp"
            android:text="密码"
            android:textColor="#000"
            android:textSize="20sp"
            />
        <EditText
            android:id="@+id/et_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:background="@null"
            android:hint="请输入密码"
            android:inputType="textPassword"
            android:padding="10dp"
            />
    </LinearLayout>
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:orientation="horizontal"
        >

        <CheckBox
            android:id="@+id/cb_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentStart="true"
            android:layout_alignParentTop="true"
            android:layout_marginStart="3dp"
            android:layout_marginTop="19dp"
            android:text="记住密码"
            android:textSize="20sp"
            />

        <CheckBox
            android:id="@+id/cb_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentStart="true"
            android:layout_alignParentTop="true"
            android:layout_marginStart="140dp"
            android:layout_marginTop="19dp"
            android:text="自动登录"
            android:textSize="20sp"
            />

        <Button
            android:id="@+id/btn_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="280dp"
            android:layout_marginTop="15dp"
            android:background="#2481BE"
            android:text="登录"
            android:textColor="@android:color/white"
            android:textSize="20sp" />

    </RelativeLayout>


</LinearLayout>