归档—SharedPreferences（轻量级存储）

<p style="margin-top: 0px; margin-bottom: 0px; padding-top: 0px; padding-bottom: 0px; font-family: Arial; font-size: 14px; line-height: 26px;">SharedPreferences(轻量级的存储)，通常我们可以用它来记录一些小的数据，例如我们可以记录用户的账号及密码，以便用户下次登录不需要重复输入。</p><p style="margin-top: 0px; margin-bottom: 0px; padding-top: 0px; padding-bottom: 0px; font-family: Arial; font-size: 14px; line-height: 26px;">示例代码：</p>

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener{

private EditText pass;
private EditText user;
private SharedPreferences sp;
private String strPass;
private String strUser;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button but= (Button) findViewById(R.id.but);
but.setOnClickListener(this);
pass = (EditText) findViewById(R.id.edi_pass);
user = (EditText) findViewById(R.id.edi_user);
sp = this.getSharedPreferences("sp", Context.MODE_PRIVATE);
String u = sp.getString("user","");
String p = sp.getString("pass", null);

if("".equals(u) || p != null){
user.setText(u);
pass.setText(p);
}
}

@Override
public void onClick(View v) {
strPass = pass.getText().toString().trim();
strUser = user.getText().toString().trim();
Toast.makeText(this, "账号："+strUser+" 密码："+strPass, Toast.LENGTH_SHORT).show();
if ("123".equals(strUser) && "12345".equals(strPass)) {
Toast.makeText(this, "输入正确", Toast.LENGTH_SHORT).show();
Editor edi=sp.edit();
boolean is=sp.getBoolean("isf", true);
if (is) {
edi.putBoolean("isf", false);

}else{

}
edi.putString("pass", strPass);
edi.putString("user", strUser);
edi.commit();
}else{
Toast.makeText(this, "输入错误", Toast.LENGTH_SHORT).show();
}
}

}

布局：

<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:orientation="vertical" >

<EditText
android:id="@+id/edi_user"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="账号" />

<EditText
android:id="@+id/edi_pass"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="密码" />

<Button
android:id="@+id/but"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="登录" />

</LinearLayout>