第十一周十二周作业

1.图片一 用内部存储实现文件写入和读取功能

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:id="@+id/et1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="输入你想输入的内容" />
<Button
android:id="@+id/bt1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="写入"
android:onClick="click1"/>
<EditText
android:id="@+id/et2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="显示读取的内容" />
<Button
android:id="@+id/bt2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="读取"
android:onClick="click2"/>

package com.example.se;
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 et1 = findViewById(R.id.et1);
EditText et2 = findViewById(R.id.et2);
String filename = "data.txt";
String content = et1.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 et2 = 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();
}
}
et2.setText(content);
}
}

2.图片二 使用sharedpreference实现记住密码功能

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/tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="账号"
android:layout_marginLeft="50dp"
android:layout_marginTop="10dp"
/>
<EditText
android:id="@+id/et1"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:hint="请输入用户名"
android:layout_toRightOf="@id/tv1"/>
<TextView
android:id="@+id/tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:text="密码"
android:layout_marginTop="10dp"
android:layout_below="@id/et1"/>
<EditText
android:id="@+id/et2"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:hint="请输入密码"
android:layout_below="@id/et1"
android:layout_toRightOf="@id/tv2"/>
<Button
android:id="@+id/bt1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="登录"
android:textColor="#00FFFF"
android:background="#076453"
android:layout_below="@id/cb1"
android:layout_marginLeft="280dp"/>
<CheckBox
android:id="@+id/cb1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="记住密码"
android:layout_below="@id/et2"
android:layout_marginTop="10dp"
android:layout_marginLeft="50dp"/>
<CheckBox
android:id="@+id/cb2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="自动登录"
android:layout_below="@id/et2"
android:layout_toRightOf="@id/cb1"
android:layout_marginTop="10dp"
android:layout_marginLeft="20dp"/>

package com.example.we;
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 userInfo=re.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.et1);
et_password=(EditText)findViewById(R.id.et2);
btn_login=(Button)findViewById(R.id.bt1);
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.bt1:
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=re.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();
}
}
}
}

package com.example.we;
import java.util.HashMap;
import java.util.Map;
import android.content.Context;
import android.content.SharedPreferences;
public class re{
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;
}
public static Map getUserInfo(Context context){
SharedPreferences sp=context.getSharedPreferences("data", context.MODE_PRIVATE);
String account=sp.getString("Username", null);
String password=sp.getString("pwd", null);
Map userMap=new HashMap();
userMap.put("account", account);
userMap.put("password", password);
return userMap;
}
}