1.
package com.example.innerfilesave; 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.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.b1); findViewById(R.id.b2); EditText editText1=findViewById(R.id.et_in); EditText editText2=findViewById(R.id.et_out); } public void click1(View view){ EditText editText1=findViewById(R.id.et_in); EditText editText2=findViewById(R.id.et_out); 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_SHORT).show(); } public void click2(View view){ EditText editText2=findViewById(R.id.et_out); 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" tools:context=".MainActivity" android:orientation="vertical"> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="输入你想要写入的内容" android:layout_margin="10dp" android:id="@+id/et_in"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="写入" android:layout_margin="10dp" android:id="@+id/b1" android:onClick="click1"/> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="显示读取的内容" android:layout_margin="10dp" android:id="@+id/et_out"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="读取" android:layout_margin="10dp" android:id="@+id/b2" android:onClick="click2"/> </LinearLayout>
2.
package com.example.myapplication; 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; public class MainActivity extends Activity 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=qq.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.user); et_password=(EditText)findViewById(R.id.password); btn_login=(Button)findViewById(R.id.b1); btn_login.setOnClickListener(this); CheckBox cb1=findViewById(R.id.cb1); cb1.setOnCheckedChangeListener(this); CheckBox cb2=findViewById(R.id.cb2); cb2.setOnCheckedChangeListener(this); } @Override public void onClick(View v) { // TODO Auto-generated method stub switch(v.getId()){ case R.id.b1: 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(); } } @Override public void onCheckedChanged(CompoundButton compoundButton, boolean b) { switch (compoundButton.getId()){ case R.id.cb1 : String account=et_account.getText().toString().trim(); String password=et_password.getText().toString(); boolean isSaveSuccess=qq.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.cb2: 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(); } } } }
<?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout 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/zhanghu" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="账号" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.041" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.081" /> <EditText android:id="@+id/user" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginStart="52dp" android:layout_marginLeft="52dp" android:layout_toRightOf="@id/zhanghu" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.064" /> <TextView android:id="@+id/mima" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/zhanghu" android:text="密码" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.041" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.186" /> <EditText android:id="@+id/password" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/user" android:layout_marginStart="52dp" android:layout_marginLeft="52dp" android:layout_toRightOf="@id/mima" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.193" /> <Button android:id="@+id/b1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/cb2" android:layout_alignRight="@+id/password" android:layout_alignBottom="@+id/cb2" android:text="登录" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.894" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.276" /> <CheckBox android:id="@+id/cb1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/mima" android:layout_alignLeft="@+id/mima" android:text="记住密码" android:textSize="10sp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.0" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.27" /> <CheckBox android:id="@+id/cb2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/cb1" android:layout_alignBottom="@+id/cb1" android:layout_toRightOf="@+id/cb1" android:text="自动登录" android:textSize="10sp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.427" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.27" />
