Android開發之SharedPreferences的封裝

對於大部分初學者來講，若是想利用SharedPreferences進行數據存儲的話大部分人(包括本人)應該會這樣：

存儲：

    SharedPreferences sharedPreferences = getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);  
    Editor editor = sharedPreferences.edit();  
    editor.putString("username", "Tom");  
    editor.putInt("password", 123456);  
    editor.commit();  

獲取：

    SharedPreferences sharedPreferences = getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);  
    String username = sharedPreferences.getString("username", "");  
    int password = sharedPreferences.getInt("password", 0);  

雖然這樣作代碼沒多少，若是是對於初學者練習來講無傷大雅。可是若是你是作一個項目開發來講，裏面使用了大量的數據存數。每次都將上面的代碼一遍一遍的重複，估計能讓人崩潰。因此，對於實際項目開發來講，最好能將能夠封裝的工具類封裝就進行封裝。

下面是一個封裝好的SharedPreferences的工具類，若是你有須要直接引用就OK：

package com.example.utl;

import java.util.Map;

import android.content.Context;
import android.content.SharedPreferences;

/**
 * 保存信息配置類
 * 
 * @author admin
 */
public class SharedPreferencesHelper {
    private SharedPreferences sharedPreferences;
    /*
     * 保存手機裏面的名字
     */private SharedPreferences.Editor editor;

    public SharedPreferencesHelper(Context context,String FILE_NAME) {
        sharedPreferences = context.getSharedPreferences(FILE_NAME,
                Context.MODE_PRIVATE);
        editor = sharedPreferences.edit();
    }

    /**
     * 存儲
     */
    public void put(String key, Object object) {
        if (object instanceof String) {
            editor.putString(key, (String) object);
        } else if (object instanceof Integer) {
            editor.putInt(key, (Integer) object);
        } else if (object instanceof Boolean) {
            editor.putBoolean(key, (Boolean) object);
        } else if (object instanceof Float) {
            editor.putFloat(key, (Float) object);
        } else if (object instanceof Long) {
            editor.putLong(key, (Long) object);
        } else {
            editor.putString(key, object.toString());
        }
        editor.commit();
    }

    /**
     * 獲取保存的數據
     */
    public Object getSharedPreference(String key, Object defaultObject) {
        if (defaultObject instanceof String) {
            return sharedPreferences.getString(key, (String) defaultObject);
        } else if (defaultObject instanceof Integer) {
            return sharedPreferences.getInt(key, (Integer) defaultObject);
        } else if (defaultObject instanceof Boolean) {
            return sharedPreferences.getBoolean(key, (Boolean) defaultObject);
        } else if (defaultObject instanceof Float) {
            return sharedPreferences.getFloat(key, (Float) defaultObject);
        } else if (defaultObject instanceof Long) {
            return sharedPreferences.getLong(key, (Long) defaultObject);
        } else {
            return sharedPreferences.getString(key, null);
        }
    }

    /**
     * 移除某個key值已經對應的值
     */
    public void remove(String key) {
        editor.remove(key);
        editor.commit();
    }

    /**
     * 清除全部數據
     */
    public void clear() {
        editor.clear();
        editor.commit();
    }

    /**
     * 查詢某個key是否存在
     */
    public Boolean contain(String key) {
        return sharedPreferences.contains(key);
    }

    /**
     * 返回全部的鍵值對
     */
    public Map<String, ?> getAll() {
        return sharedPreferences.getAll();
    }
}

登陸界面：

 Activity中應用：

/**
 * 登陸界面
 * 
 * @author admin
 * 
 */
public class LoginActivity extends Activity implements OnClickListener {
    private EditText username;
    private EditText password;
    private Button login;// 登陸按鈕
    private CheckBox holdPwd;// 保存用戶和密碼
    private MyDialog mydialog;// 自定義對話框
    private SharedPreferencesHelper sharedPreferencesHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_login);

        init();
    }

    /**
     * 初始化界面
     */
    private void init() {
        sharedPreferencesHelper = new SharedPreferencesHelper(
                LoginActivity.this, "anhua");
        username = (EditText) findViewById(R.id.username);
        password = (EditText) findViewById(R.id.password);
        holdPwd = (CheckBox) findViewById(R.id.login_hold);
        holdPwd.setChecked(true);
　　　　 //取出存儲的值在登錄界面中顯示
        username.setText(sharedPreferencesHelper.getSharedPreference("username", "").toString().trim());
        password.setText(sharedPreferencesHelper.getSharedPreference("password", "").toString().trim());

        login = (Button) findViewById(R.id.login);
        login.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.login:
            login();
            break;
        default:
            break;
        }
    }

    private void login() {
        String name = username.getText().toString().trim();
        String pwd = password.getText().toString().trim();
　　　　　//若是複選框被選中則存儲帳戶和密碼 if (holdPwd.isChecked()) {
            sharedPreferencesHelper.put("username", name);
            sharedPreferencesHelper.put("password", pwd);
            sharedPreferencesHelper.put("isremember", holdPwd.isChecked());
        } else {
　　　　　　　//若是複選框未被選中則清除記錄的帳號和密碼
            sharedPreferencesHelper.remove("username");
            sharedPreferencesHelper.remove("password");
            sharedPreferencesHelper.remove("isremember");
        }
        login.setBackgroundResource(R.drawable.bg_login_submit);
        login.setTextColor(getResources().getColor(R.color.white));
        Intent intent = new Intent(LoginActivity.this, MainActivity.class);
        startActivity(intent);
        finish();
    }
}