Android之SharedPreferences保存数据应用之qq登录记住密码

<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:gravity="center_horizontal"
    android:orientation="vertical">
	<ImageView 
	    android:id="@+id/logo"
	    android:layout_width="100dp"
	    android:layout_height="100dp"
	    android:src="@drawable/qq"/>
	<EditText 
	    android:id="@+id/et_qq"
	    android:layout_width="match_parent"
	    android:layout_height="wrap_content"
	    android:inputType="number"
	    android:hint="QQ号"/>
	<EditText 
	    android:id="@+id/et_pw"
	    android:layout_width="match_parent"
	    android:layout_height="wrap_content"
	    android:inputType="textPassword"
	    android:hint="密码"/>
	<CheckBox 
	    android:id="@+id/cb_cb"
	    android:layout_width="fill_parent"
	    android:layout_height="wrap_content"
	    android:text="记住密码"/>
	<Button 
	    android:id="@+id/bt_login"
	    android:layout_width="200dp"
	    android:layout_height="wrap_content"
	    android:onClick="login"
	    android:text="登录"/>
   
</LinearLayout>

package com.example.qqlogin;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;

import android.renderscript.ProgramFragmentFixedFunction.Builder.Format;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.ShareActionProvider;
import android.text.TextUtils;
import android.text.format.Formatter;
import android.util.Log;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.os.Environment;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends ActionBarActivity {
	private static final String TAG = "LoginActivity";
	private EditText et_qq;
	private EditText et_pw;
	private CheckBox cb_cb;
	private Button bt_login;
	//1.声明sp
	private SharedPreferences sp;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_login);
		et_qq=(EditText)findViewById(R.id.et_qq);
		et_pw=(EditText)findViewById(R.id.et_pw);
		cb_cb=(CheckBox)findViewById(R.id.cb_cb);
		bt_login=(Button)findViewById(R.id.bt_login);
		//2.获得一个参数
		sp=this.getSharedPreferences("context", 0);
		String qq=sp.getString("qq", "");
		String pw=sp.getString("pw", "");
		et_qq.setText(qq);
		et_pw.setText(pw);
	}
	
	public void login(View v){
		String qq=et_qq.getText().toString().trim();
		String pw=et_pw.getText().toString().trim();
		if(TextUtils.isEmpty(qq)||TextUtils.isEmpty(pw)){
			Toast.makeText(LoginActivity.this, "密码账号不能为空", 0).show();
			return;
		}
		if(cb_cb.isChecked()){//记住密码
			Log.i(TAG,"记住密码");
			//3.得到sp的文件编辑器
			Editor editor=sp.edit();
			editor.putString("qq", qq);
			editor.putString("pw", pw);
			//4.保存数据完毕一定要记的调用commit();
			editor.commit();
		}else{//不需要记住密码
			Log.i(TAG,"不需要记住密码");
		}
	}
}