第十一，十二周作业
图片一 用内部存储实现文件写入和读取功能
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".MainActivity"> <EditText android:id="@+id/et_1" android:layout_width="300dp" android:layout_height="wrap_content" android:hint="请输入你想写的内容" android:textSize="80px" /> <Button android:id="@+id/btn_1" android:layout_width="150dp" android:layout_height="wrap_content" android:text="写入" android:onClick="click1" android:textSize="80px" /> <EditText android:id="@+id/et_2" android:layout_width="300dp" android:layout_height="wrap_content" android:hint="显示读取的内容" android:textSize="80px" /> <Button android:id="@+id/btn_2" android:layout_width="150dp" android:layout_height="wrap_content" android:text="读取" android:onClick="click2" android:textSize="80px" /> </LinearLayout>
package com.example.a11121; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.Toast; import java.io.EOFException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void click1(View view){ EditText editText=findViewById(R.id.et_1); 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 { try { if (fos!=null){ 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.et_2); 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 { try { if (fis!=null){ fis.close(); } }catch (IOException e){ e.printStackTrace(); } } editText.setText(content); Toast.makeText(this, "读取成功", Toast.LENGTH_SHORT).show(); } }
图片二 使用sharedpreference实现记住密码功能
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <TextView android:id="@+id/account" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="账号：" android:textSize="30sp" android:layout_marginTop="30dp" android:layout_marginLeft="20dp" android:textColor="#000000" android:padding="10dp" /> <EditText android:id="@+id/et_1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_toRightOf="@+id/account" android:layout_marginTop="30dp" android:hint="请输入用户名" android:padding="10dp" android:textSize="30sp" /> <TextView android:id="@+id/password" android:layout_below="@+id/account" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="密码：" android:textSize="30sp" android:layout_marginTop="30dp" android:layout_marginLeft="20dp" android:textColor="#000000" android:padding="10dp" /> <EditText android:id="@+id/et_2" android:layout_below="@+id/et_1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_toRightOf="@+id/account" android:layout_marginTop="30dp" android:hint="请输入密码" android:padding="10dp" android:textSize="30sp" /> <CheckBox android:id="@+id/cb_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="记住密码" android:textSize="20sp" android:layout_below="@+id/et_2" android:layout_marginLeft="30dp" android:layout_marginTop="20dp" /> <CheckBox android:id="@+id/cb_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="自动登录" android:textSize="20sp" android:layout_below="@+id/et_2" android:layout_marginLeft="20dp" android:layout_marginTop="20dp" android:layout_toRightOf="@+id/cb_1" /> <Button android:id="@+id/btn_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="登录" android:textSize="20sp" android:layout_below="@+id/et_2" android:layout_toRightOf="@+id/cb_2" android:layout_marginTop="15dp" android:layout_marginLeft="20dp" /> </RelativeLayout>
package com.example.a11122; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.text.TextUtils; 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 java.util.Map; public class MainActivity extends AppCompatActivity implements android.view.View.OnClickListener, CompoundButton.OnCheckedChangeListener { private EditText et_1; private EditText et_2; private Button btn_1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); Map<String,String> userInfo=SPSaveQQ.getUserInfo(this); if(userInfo!=null){ et_1.setText(userInfo.get("account")); et_2.setText(userInfo.get("password")); } } private void initView() { et_1=findViewById(R.id.et_1); et_2=findViewById(R.id.et_2); btn_1=findViewById(R.id.btn_1); btn_1.setOnClickListener(this); CheckBox cb1=findViewById(R.id.cb_1); cb1.setOnCheckedChangeListener(this); CheckBox cb2=findViewById(R.id.cb_2); cb2.setOnCheckedChangeListener(this); } @Override public void onClick(View view) { switch (view.getId()){ case R.id.btn_1: String account=et_1.getText().toString().trim(); String password=et_2.getText().toString(); if(TextUtils.isEmpty(account)){ Toast.makeText(this,"请输入QQ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(); } } @Override public void onCheckedChanged(CompoundButton compoundButton, boolean b) { switch (compoundButton.getId()){ case R.id.cb_1: String account=et_1.getText().toString().trim(); String password=et_2.getText().toString(); boolean isSaveSuccess=SPSaveQQ.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_1.setText(null); et_2.setText(null); } break; case R.id.cb_2: account=et_1.getText().toString().trim(); password=et_2.getText().toString(); if(TextUtils.isEmpty(account)){ Toast.makeText(this,"请输入账号",Toast.LENGTH_LONG).show(); return; } if(TextUtils.isEmpty(password)){ Toast.makeText(this,"请输入密码",Toast.LENGTH_LONG).show(); return; } if(b) Toast.makeText(this,"登录成功",Toast.LENGTH_LONG).show(); else { Toast.makeText(this,"请登录",Toast.LENGTH_LONG).show(); } } } }
package com.example.a11122; import android.content.Context; import android.content.SharedPreferences; import java.util.HashMap; import java.util.Map; public class SPSaveQQ { public static boolean saveUserInfo(Context context, String account, String 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("Username",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; } }
