第十一周十二周作业
图片一 用内部存储实现文件写入和读取功能
package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.icu.text.UnicodeSetSpanner; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.Toast; import java.io.FileInputStream; import java.io.FileNotFoundException; 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); findViewById(R.id.btn_1); findViewById(R.id.btn_2); } public void click1(View view) { EditText editText1 = findViewById(R.id.et_1); EditText editText2 = findViewById(R.id.et_2); String filename = "data.txt"; String context = editText1.getText().toString(); FileOutputStream fos = null; try { fos = openFileOutput(filename, MODE_PRIVATE); fos.write(context.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_LONG).show(); } public void click2(View view) { EditText editText2 = findViewById(R.id.et_2); String context = ""; FileInputStream fis = null; try { fis = openFileInput("data.txt"); byte[] buffer = new byte[fis.available()]; fis.read(buffer); context = new String(buffer); } catch (Exception e) { e.printStackTrace(); } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { e.printStackTrace(); } } } editText2.setText(context); } }
<?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" android:background="#F8E7FC" tools:context=".MainActivity"> <EditText android:id="@+id/et_1" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入想写入的内容" android:textSize="20sp" android:layout_margin="20dp" android:padding="10dp"/> <Button android:id="@+id/btn_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="保存" android:textColor="#000000" android:textSize="20sp" android:layout_marginLeft="25dp" android:padding="10dp" android:onClick="click1"/> <EditText android:id="@+id/et_2" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="显示读取的内容" android:textSize="20sp" android:layout_margin="20dp" android:padding="10dp"/> <Button android:id="@+id/btn_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="读取" android:textColor="#000000" android:textSize="20sp" android:layout_marginLeft="25dp" android:padding="10dp" android:onClick="click2"/> </LinearLayout>
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" android:background="#FADFE9" tools:context=".MainActivity"> <TextView android:id="@+id/tv_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="账号" android:textColor="#000000" android:textSize="20sp" android:layout_marginTop="30dp" android:layout_marginLeft="20dp" android:padding="10dp"/> <EditText android:id="@+id/et_1" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入用户名" android:layout_toRightOf="@id/tv_1" android:layout_marginTop="30dp" android:padding="10dp" android:textSize="20sp"/> <TextView android:id="@+id/tv_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="密码" android:textColor="#000000" android:textSize="20sp" android:layout_marginTop="30dp" android:layout_marginLeft="20dp" android:layout_below="@id/tv_1" android:padding="10dp"/> <EditText android:id="@+id/et_2" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入密码" android:layout_toRightOf="@id/tv_2" android:layout_below="@id/et_1" android:layout_marginTop="30dp" android:padding="10dp" android:textSize="20sp"/> <CheckBox android:id="@+id/cb_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="记住密码" android:textColor="#000000" android:textSize="18sp" android:layout_below="@id/tv_2" android:padding="5dp" android:layout_marginTop="30dp" android:layout_marginLeft="20dp"/> <CheckBox android:id="@+id/cb_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="自动登录" android:textColor="#000000" android:textSize="18sp" android:layout_below="@id/tv_2" android:layout_toRightOf="@id/cb_1" android:padding="5dp" android:layout_marginTop="30dp" android:layout_marginLeft="20dp"/> <Button android:id="@+id/btn_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="登录" android:textColor="#000000" android:textSize="18sp" android:layout_below="@id/tv_2" android:padding="5dp" android:layout_marginTop="25dp" android:layout_marginLeft="20dp" android:layout_toRightOf="@id/cb_2"/> </RelativeLayout>
package com.example.myapplication; 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_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=MainActivity1.getUserInfo(this); if(userInfo!=null){ et_account.setText(userInfo.get("account")); et_password.setText(userInfo.get("password")); } } private void initView() { et_account=findViewById(R.id.et_1); et_password=findViewById(R.id.et_2); btn_login=findViewById(R.id.btn_1); btn_login.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_account.getText().toString().trim(); String password=et_password.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; } Toast.makeText(this,"登录成功",Toast.LENGTH_LONG).show(); } } @Override 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=MainActivity1.saveUserInfo(this,account,password); if(isSaveSuccess&&b){ Toast.makeText(this,"保存成功",Toast.LENGTH_LONG).show(); }else { Toast.makeText(this,"保存失败",Toast.LENGTH_LONG).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_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.myapplication; import android.content.Context; import android.content.SharedPreferences; import java.util.HashMap; import java.util.Map; public class MainActivity1 { 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; } public static boolean saveUserInfo(Context context, String account, String password) { SharedPreferences sp=context.getSharedPreferences("data",context.MODE_PRIVATE); SharedPreferences.Editor editor=sp.edit(); editor.putString("Username",account); editor.putString("pwd",password); editor.commit(); return true; } }
