android文件存储和SharedPreferences存储的方法

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演示

【文件存储】中查看设备保存的文件

目录

activity_main

<?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:background="#E6E6E6"    android:orientation="vertical"    android:padding="10dp"    tools:context=".MainActivity">    <ImageView        android:layout_width="70dp"        android:layout_height="70dp"        android:layout_centerHorizontal="true"        android:layout_gravity="center_horizontal"        android:layout_marginTop="30dp"        android:src="@drawable/head" />    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="15dp"        android:background="@android:color/white"        android:orientation="horizontal">        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:padding="10dp"            android:text="账号:"            android:textColor="#000"            android:textSize="20sp" />        <EditText            android:id="@+id/et_account"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_marginLeft="5dp"            android:background="@null"            android:padding="10dp" />    </LinearLayout>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="10dp"        android:background="@android:color/white"        android:orientation="horizontal">        <TextView            android:id="@+id/tv_passWord"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:padding="10dp"            android:text="密码:"            android:textColor="#000"            android:textSize="20sp" />        <EditText            android:id="@+id/et_password"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:layout_marginLeft="5dp"            android:background="@null"            android:inputType="textPassword"            android:padding="10dp" />    </LinearLayout>    <Button        android:id="@+id/btn_login"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="25dp"        android:background="#3C8DC4"        android:text="登录"        android:textColor="@android:color/white"        android:textSize="20sp" /></LinearLayout>

MainActivity

public class MainActivity extends AppCompatActivity {    private EditText et_account, et_password; //账号输入框、密码输入框    private Button loginBtn; //登录按钮    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();    }    private void initView() {        et_account = findViewById(R.id.et_account);        et_password = findViewById(R.id.et_password);        loginBtn = findViewById(R.id.btn_login);        //点击监听事件        loginBtn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                switch (view.getId()) {                    case R.id.btn_login:                        //当点击登录按钮时，获取界面上输入的 QQ 账号和密码                        String account = et_account.getText().toString().trim();                        String password = et_password.getText().toString();                        //检验输入的账号和密码是否为空                        if (TextUtils.isEmpty(account)) {                            Toast.makeText(getApplicationContext(), "请输入 QQ 账号", Toast.LENGTH_SHORT).show();                            return;                        }                        if (TextUtils.isEmpty(password)) {                            Toast.makeText(getApplicationContext(), "请输入密码", Toast.LENGTH_SHORT).show();                            return;                        }                        //文件存储                        //saveOfFile(account,password);                        //SharedPreferences存储                        saveOfSharedPreferences(account,password);                        break;                }            }        });    }    //SharedPreferences存储    private void saveOfSharedPreferences(String account, String password) {        //获取 QQ 账号和密码信息        SharedPreferences userInfo=SPSaveQQ.getUserInfo(getApplicationContext());        if (userInfo.getString("username", "") != null&&userInfo.getString("pwd", "") != null) {            String username = userInfo.getString("username", "");//读取账号            String pwd = userInfo.getString("pwd", "");//读取密码            Log.i("user", "读取用户信息");            Log.i("user", "username:" + username + "， pwd:" + pwd);            if (username.equals(account) && pwd.equals(password)) {                Toast.makeText(getApplicationContext(), username+"登录成功!", Toast.LENGTH_SHORT).show();            }else {                Log.i("user", "用户或密码错误！");                //保存用户信息                boolean isSaveSuccess = SPSaveQQ.saveUserInfo(getApplicationContext(), account, password);                if (isSaveSuccess) {                    Toast.makeText(getApplicationContext(), "保存成功!", Toast.LENGTH_SHORT).show();                } else {                    Toast.makeText(getApplicationContext(), "保存失败!", Toast.LENGTH_SHORT).show();                }            }        }else{            //保存用户信息            boolean isSaveSuccess = SPSaveQQ.saveUserInfo(getApplicationContext(), account, password);            if (isSaveSuccess) {                Toast.makeText(getApplicationContext(), "保存成功!", Toast.LENGTH_SHORT).show();            } else {                Toast.makeText(getApplicationContext(), "保存失败!", Toast.LENGTH_SHORT).show();            }        }    }    //文件存储    private void saveOfFile(String account, String password) {        //获取 QQ 账号和密码信息        Map<String, String> userInfo = FileSaveQQ.getUserInfo(getApplicationContext());        if (userInfo != null) {            //将获取的账号显示到界面上            et_account.setText(userInfo.get("account"));            //将获取的密码显示到界面上            et_password.setText(userInfo.get("password"));            Toast.makeText(getApplicationContext(), userInfo.get("account")+"登录成功!", Toast.LENGTH_SHORT).show();        }else{            //保存用户信息            boolean isSaveSuccess = FileSaveQQ.saveUserInfo(getApplicationContext(), account, password);            if (isSaveSuccess) {                Toast.makeText(getApplicationContext(), "保存成功!", Toast.LENGTH_SHORT).show();            } else {                Toast.makeText(getApplicationContext(), "保存失败!", Toast.LENGTH_SHORT).show();            }        }    }}

FileSaveQQ

public class FileSaveQQ {        public static boolean saveUserInfo(Context context, String account, String password) {        //文件的输出流对象        FileOutputStream fos = null;        try {            //获取文件的输出流对象 fos,该文件只能被当前程序读写            fos = context.openFileOutput("user.txt",                    Context.MODE_PRIVATE);            //将数据转换为字节码的形式写入 user.txt 文件中            fos.write((account + ":" + password).getBytes());            return true;        } catch (Exception e) {            e.printStackTrace();            return false;        }finally {            try {                if(fos != null){                    fos.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }        public static Map<String, String> getUserInfo(Context context) {        String content = "";        //文件的输入流对象        FileInputStream fis = null;        try {            //获取文件的输入流对象 fis            fis = context.openFileInput("user.txt");            //将输入流对象中的数据转换为字节码的形式            byte[] buffer = new byte[fis.available()];            //通过 read()方法读取字节码中的数据            fis.read(buffer);            //将获取的字节码转换为字符串            content = new String(buffer);            Map<String, String> userMap = new HashMap<String, String>();            String[] infos = content.split(":");            //放入账号密码            userMap.put("account", infos[0]);            userMap.put("password", infos[1]);            Log.i("user", "读取用户信息");            Log.i("user", "account:" + infos[0] + "， password:" + infos[1]);            return userMap;        } catch (Exception e) {            e.printStackTrace();            return null;        } finally {            try {                if (fis != null) {                    fis.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }}

SPSaveQQ

public class SPSaveQQ {        public static boolean saveUserInfo(Context context, String account, String password){        SharedPreferences sharedPreferences = null;        try {            sharedPreferences = context.getSharedPreferences("user", Context.MODE_PRIVATE);            SharedPreferences.Editor editor = sharedPreferences.edit();//获取编辑器            editor.putString("username", account);            editor.putString("pwd", password);            editor.commit();//提交修改            return true;        }catch (Exception e){            e.printStackTrace();            return false;        }finally {            if(sharedPreferences != null){                return true;            }            return false;        }    }            public static SharedPreferences getUserInfo(Context context){        SharedPreferences userInfo = context.getSharedPreferences("user", Context.MODE_PRIVATE);        return userInfo;    }}

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