SharePreferences是使用键值对方式存储的,即当保存一条数据,需提供一个对应的键值,通过对应的键值取出数据:
下面是一个简单的用SharePreferences来存账号和密码以达到保存效果:
两个界面LoginActivity(首界面)和MainActivity,在首界面布局:
代码
package com.example.snake.sharedpreferencesrremeberpassward;
import android.content.Intent;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;
public class LoginActivity extends AppCompatActivity {
private SharedPreferences pref;
private SharedPreferences.Editor editor;
private EditText accoutText;
private EditText passwordText;
private CheckBox remberpassword;
private Button login;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
pref = PreferenceManager.getDefaultSharedPreferences(this);
accoutText = (EditText)findViewById(R.id.accoutText);
passwordText = (EditText)findViewById(R.id.passwardText);
remberpassword = (CheckBox)findViewById(R.id.checkBox);
boolean isRemember = pref.getBoolean("rember_password",false);
if(isRemember){
//如果点了复选框这里则把内容记录下来设置回文本框内
String accout = pref.getString("accout", "");
String password = pref.getString("password", "");
accoutText.setText(accout);
passwordText.setText(password);
}
login = (Button)findViewById(R.id.button);
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String account = accoutText.getText().toString();
String password = passwordText.getText().toString();
//设置账号(admin)和密码(123),若不是则报错
if(account.equals("admin") && password.equals("123")){
editor = pref.edit();
//判断是否点击复选框,若是点了,则把账号和密码数据保存到对应得键中
if(remberpassword.isChecked()){
editor.putBoolean("rember_password",true);
editor.putString("accout",account);
editor.putString("password",password);
} else {
editor.clear();
}
editor.apply();
Intent intent =new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
} else {
Toast.makeText(LoginActivity.this, "accout or password is invalid", Toast.LENGTH_SHORT).show();
}
}
});
}
}
这里对应得SharedPreferences.Editor editor是为了写入,即把EditText内容保存起来(文件应该在 包名/shared_prefs/data.xml), SharedPreferences pref是为了读取数据
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