Android的SharedPreferences存储

package com.t20.fileop;
/**
 * SharedPreferences存储
 */
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.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class SPActivity extends Activity {

	private EditText et_content;
	private TextView tv_content;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_sp);
		//输入框
		et_content=(EditText) findViewById(R.id.et_content);
		//文本框
		tv_content=(TextView) findViewById(R.id.tv_content);
	}
	/**
	 * 保存数据到SharedPreferences中
	 * @param v
	 */
	public void saveSP(View v){
		String content=et_content.getText().toString();
		if(content.isEmpty()){
			Toast.makeText(SPActivity.this, "请输入内容", Toast.LENGTH_SHORT).show();
			return;
		}
		//获取SharedPreferences（关联共享）对象
		SharedPreferences sp= getSharedPreferences("dataSP", Context.MODE_PRIVATE);//后缀名不用写，默认是.xml
		//获取SharedPreferences（关联共享）的编辑器
		Editor editor=sp.edit();
		editor.putString("content", content);
		//提交事务
		boolean flag=editor.commit();
		if(flag){
			Toast.makeText(SPActivity.this, "成功存入SharedPreferences", Toast.LENGTH_SHORT).show();
		}
	}
	/**
	 * 从SharedPreferences中读取数据
	 * @param v
	 */
	public void readSP(View v){
		//获取SharedPreferences（关联共享）对象
		SharedPreferences sp= getSharedPreferences("dataSP", Context.MODE_PRIVATE);//后缀名不用写，默认是.xml
		 String content=sp.getString("content", "无数据");
		//------------------------------键-------默认值
		 tv_content.setText(content);
	}
}