public class MainActivity

         extends AppCompatActivity

         implements View.OnClickListener {

     private EditText mEtName;

     private EditText mEtPassword;

     private CheckBox mCbMark;

     private Button   mBtnOk;

     private final String KEY_NAME     = "name";

     private final String KEY_PASSWORD = "password";

     private final String KEY_MARK     = "mark";

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         initViews();

     }

     @Override

     public void onClick(View v) {

         String name = mEtName.getText().toString().trim();

         String password = mEtPassword.getText().toString().trim();

         if ("".equalsIgnoreCase(name) || "".equalsIgnoreCase(password)) {

             Toast.makeText(this, "账号和密码不能为空！", Toast.LENGTH_LONG).show();

         }

         else {

             SharedPreferences userInfo = getSharedPreferences("user_info", MODE_PRIVATE);

             SharedPreferences.Editor editor = userInfo.edit();

             editor.putString(KEY_NAME, name);

             editor.putBoolean(KEY_MARK, mCbMark.isChecked());

             if (mCbMark.isChecked()) {

                 editor.putString(KEY_PASSWORD, password);

             }

             else {

                 editor.putString(KEY_PASSWORD, "");

             }

             editor.apply();//---应用操作

             Toast.makeText(this, "用户信息保存成功！", Toast.LENGTH_LONG).show();

         }

     }

     private void initViews() {

         SharedPreferences userInfo = getSharedPreferences("user_info", MODE_PRIVATE);

         mEtName     = (EditText)findViewById(R.id.etName);

         mEtPassword = (EditText)findViewById(R.id.etPassword);

         mCbMark     = (CheckBox)findViewById(R.id.cbMark);

         mBtnOk      = (Button)findViewById(R.id.btnOk);

         mBtnOk.setOnClickListener(this);

         mEtName.setText(userInfo.getString(KEY_NAME, ""));

         if (userInfo.getBoolean(KEY_MARK, true)) {

             mEtPassword.setText(userInfo.getString(KEY_PASSWORD, ""));

             mCbMark.setChecked(true);

         }

         else {

             mEtPassword.setText("");

             mCbMark.setChecked(false);

         }

     }

 }

 <?xml version="1.0" encoding="utf-8"?>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     xmlns:tools="http://schemas.android.com/tools"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:paddingBottom="@dimen/activity_vertical_margin"

     android:paddingLeft="@dimen/activity_horizontal_margin"

     android:paddingRight="@dimen/activity_horizontal_margin"

     android:paddingTop="@dimen/activity_vertical_margin"

     tools:context="com.haoye.preferencestest.MainActivity"

     android:orientation="vertical"

     android:gravity="center_horizontal"

     android:weightSum="100">

     <EditText

         android:id="@+id/etName"

         android:layout_marginTop="20dp"

         android:layout_width="300dp"

         android:layout_height="50dp"

         android:textSize="24sp"

         android:hint="@string/name_hint"/>

     <EditText

         android:id="@+id/etPassword"

         android:layout_marginTop="20dp"

         android:layout_width="300dp"

         android:layout_height="50dp"

         android:inputType="textPassword"

         android:textSize="24sp"

         android:hint="@string/password_hint"/>

     <CheckBox

         android:id="@+id/cbMark"

         android:layout_width="wrap_content"

         android:layout_height="wrap_content"

         android:checked="true"

         android:text="@string/cb_mark"/>

     <Button

         android:id="@+id/btnOk"

         android:layout_marginTop="20dp"

         android:layout_width="wrap_content"

         android:layout_height="wrap_content"

         android:text="@string/btn_ok"/>

 </LinearLayout>

<resources>

    <string name="app_name">PreferencesTest</string>

    <string name="name_hint">请输入用户名</string>

    <string name="password_hint">请输入密码</string>

    <string name="btn_ok">确定</string>

    <string name="cb_mark">记住密码</string>

</resources>