安卓第十一,十二周作业
1.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" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <EditText android:id="@+id/et_xieru" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入你想写入的内容" android:textSize="30dp" android:layout_marginTop="20dp"/> <Button android:id="@+id/bt_xieru" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click1" android:text="写入" android:textSize="30dp" android:layout_marginLeft="20dp" /> <EditText android:id="@+id/et_duqu" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="显示读取的内容" android:textSize="30dp" android:layout_marginTop="20dp"/> <Button android:id="@+id/bt_duqu" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click2" android:text="读取" android:textSize="30dp" android:layout_marginLeft="20dp" /> </LinearLayout>
package com.example.myapplication11 import android.content.Context import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.Toast; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) findViewById<View>(R.id.bt_xieru) findViewById<View>(R.id.bt_duqu) val editText1 = findViewById<EditText>(R.id.et_xieru) val editText2 = findViewById<EditText>(R.id.et_duqu) } fun click1(view: View?) { val editText1 = findViewById<EditText>(R.id.et_xieru) val editText2 = findViewById<EditText>(R.id.et_duqu) val fileName = "data.txt" val context = editText1.text.toString() var fos: FileOutputStream? = null try { fos = openFileOutput(fileName, Context.MODE_PRIVATE) fos.write(context.toByteArray()) } catch (e: Exception) { e.printStackTrace() } finally { if (fos != null) { try { fos.close() } catch (e: IOException) { e.printStackTrace() } } } Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show() } fun click2(view: View?) { val editText2 = findViewById<EditText>(R.id.et_duqu) var context: String? = "" var fis: FileInputStream? = null try { fis = openFileInput("data.txt") val buffer = ByteArray(fis.available()) fis.read(buffer) context = String(buffer) } catch (e: Exception) { e.printStackTrace() } finally { if (fis != null) { try { fis.close() } catch (e: IOException) { e.printStackTrace() } } } editText2.setText(context) } }
2. 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.gyg; 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; } }