Android SharedPreferences一般的读写 的用法。

Android SharedPreferences一般用于轻量级的数据存储，比如用户名和密码等。

package com.lixu.testsharepreferences;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends Activity {

    private static final String USER_NAME = "username";
    private static final String USER_PWS = "userpws";
    private String NAME = "name";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        writeSharedPreferences();
        readSharedPreferences();

    }

    // Context.MODE_PRIVATE 这个是设置访问权限 意思是只有本app可以读写里面的数据
    // 如果SharedPreferences里面没有写入数据 就返回"无值"；
    private void readSharedPreferences() {
        SharedPreferences sp = this.getSharedPreferences(NAME, Context.MODE_PRIVATE);

        String str1 = sp.getString(USER_NAME, "无值");
        String str2 = sp.getString(USER_PWS, "无值");

        Toast.makeText(getApplicationContext(), "用户名是：" + str1, 1).show();

        Toast.makeText(getApplicationContext(), "用户密码是：" + str2, 1).show();

    }

    private void writeSharedPreferences() {
        SharedPreferences sp = this.getSharedPreferences(NAME, Context.MODE_PRIVATE);

        Editor edt = sp.edit();
        edt.putString(USER_NAME, "lixu");
        edt.putString(USER_PWS, "123456789");
        // 提交
        edt.commit();

    }

}

运行效果：