1.SharedPreferences的使用
–SharedPreferences是Android平台上一个轻量级的存储类,用于存储一些应用程序的配置参数,例如用户名、密码、自定义参数的设置等。
–SharedPreferences是Android平台上一个轻量级的存储类,用于存储一些应用程序的配置参数,例如用户名、密码、自定义参数的设置等。
–SharedPreferences中存储的数据是以key/value键值对的形式保存在XML文件中,该文件位于“data/data/<packagename>/shared_prefs”文件夹中。
2.SharedPreferences的使用–存储数据
•SharedPreferences sp = getSharedPreferences("data",MODE_PRIVATE);
•Editor editor = sp.edit();
•editor.putString("name", "传智播客");
•editor.putInt("age", 8);
•editor.commit();
–取出数据
•SharedPreferences sp = context.getSharedPreferences();
•String data = sp.getString("name","");
–编辑数据
•SharedPreferences sp = context.getSharedPreferences ();
•Editor editor = sp.edit();
•editor.remove("name");
•editor.clear();
•editor.commit();
3.应用:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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" > <ImageView android:id="@+id/iv_head" android:layout_width="50dp" android:layout_height="50dp" android:layout_centerHorizontal="true" android:layout_marginTop="40dp" android:src="@drawable/dddss" /> <LinearLayout android:id="@+id/layout" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/iv_head" android:layout_margin="10dp" android:background="#ffffff" android:orientation="vertical" > <RelativeLayout android:id="@+id/rl_username" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="10dp" > <TextView android:id="@+id/tv_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:text="账号" /> <EditText android:id="@+id/et_number" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:layout_toRightOf="@+id/tv_name" android:background="@null" /> </RelativeLayout> <View android:layout_width="match_parent" android:layout_height="2dp" android:background="#E6E6E6" /> <RelativeLayout android:id="@+id/rl_userpsw" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="10dp" > <TextView android:id="@+id/tv_psw" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:text="密码" /> <EditText android:id="@+id/et_password" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:layout_toRightOf="@+id/tv_psw" android:inputType="textPassword" android:background="@null" /> </RelativeLayout> </LinearLayout> <Button android:id="@+id/btn_login" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/layout" android:layout_centerHorizontal="true" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:layout_marginTop="20dp" android:background="#3C8DC4" android:text="登录" android:textColor="#ffffff" /> </RelativeLayout>MainActivity.java代码
package com.example.zlf.demo51sharepreferences; import android.icu.text.IDNA; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.text.TextUtils; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; import java.util.Map; import java.util.concurrent.TimeUnit; public class MainActivity extends AppCompatActivity implements View.OnClickListener { private EditText etNumber; private EditText etPassword; //private Button btn_login; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView();//初始化,下面有此方法 //取出号码 Map<String,String> userInfo=Utils.getUserInfo(this); if (userInfo!=null){ etNumber.setText(userInfo.get("number")); etPassword.setText(userInfo.get("password")); } } private void initView() { etNumber=(EditText)findViewById(R.id.et_number); etPassword=(EditText)findViewById(R.id.et_password); //因为没有定义login,这里直接用findViewById findViewById(R.id.btn_login).setOnClickListener(this); } @Override public void onClick(View v) { //点击登陆时,获取QQ号和密码 String number=etNumber.getText().toString().trim(); String password=etPassword.getText().toString(); //判断你输入的QQ号和密码是否正确 if(TextUtils.isEmpty(number)){ Toast.makeText(this,"请输入QQ号",Toast.LENGTH_SHORT).show(); return; } if(TextUtils.isEmpty(password)){ Toast.makeText(this,"请输入密码",Toast.LENGTH_SHORT).show(); return; } //登陆成功 Toast.makeText(this,"登陆成功",Toast.LENGTH_SHORT).show(); Log.i("MainActivity","记住密码:"+number+","+password); //保存用户信息 boolean isSaveSuccess=Utils.saveUserInfo(this,number,password); if (isSaveSuccess){ Toast.makeText(this,"保存成功",Toast.LENGTH_SHORT).show(); }else { Toast.makeText(this,"保存失败",Toast.LENGTH_SHORT).show(); } } }Utils.java代码
package com.example.zlf.demo51sharepreferences; import android.content.Context; import android.content.SharedPreferences; import java.util.HashMap; import java.util.Map; public class Utils { public static boolean saveUserInfo(Context context, String number, String password) { SharedPreferences sp = context.getSharedPreferences("data", Context.MODE_PRIVATE);//数据自己可用 SharedPreferences.Editor edit = sp.edit(); edit.putString("userName", number); edit.putString("pwd", password); edit.commit(); return true;//存储成功 } // 从data.xml中获取QQ号码和密码 public static Map<String, String> getUserInfo(Context context) { SharedPreferences sp = context.getSharedPreferences("data", Context.MODE_PRIVATE); String number = sp.getString("userName", null); String password = sp.getString("pwd", null); Map<String,String> userMap = new HashMap<String, String>(); userMap.put("number", number); userMap.put("password", password); return userMap; } }
结果: