Android数据存储(1)少量数据保存之SharedPreferences接口实例

SharedPreferences数据保存主要是通过键值的方式存储在xml文件中

xml文件在data/此程序的包名/XX.xml

格式

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<int name="count" value="3" />
<string name="time">写入日期:2013年10月07日,时间:11:28:09</string>
</map>

SharedPreferences读写的基本步骤

读

1.通过Context的getSharedPreferences获取SharedPreferences接口的对象share：SharedPreferences share = this.getSharedPreferences("share",Context.MODE_PRIVATE);

"shre"保存的xml文件名 ,Context.MODE_PRIVATE 保存的类型为只被本程序访问 (还有MODE_WORLD_READABLE表示其余的程序能够读不能写,MODE
_WORLD_WRITEBLE能读写这两个都在api17的时候被废了)

2.通过share的getXXX的方法获取指定key的值： share.getInt("count", 0);

写

1.通过SharedPreferences对象的edit()方法获取Edit对象:Edit editor = share.edit();

2.通过editor对象的putXXX方法来写入值：editor.putInt("count", 1);

3.调用Editor的commit()方法提交修改值：editor.commit();

访问其他程序的SharedPreferences

访问其他程序的SharedPreferences 的读写唯一不同的是先的获取该程序的Context接口对象：this.createPackageContext(packageName, flags)

packageName为要该目标程序的包名,flags访问类型

其余的就和上面的步骤差不多就不再概叙

实例

<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"

    tools:context=".MainActivity" >

    <Button

        android:id="@+id/write"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

           android:layout_gravity="center_horizontal"

        android:text="写入数据" />

    <Button

        android:id="@+id/read"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

           android:layout_gravity="center_horizontal"

        android:text="读入数据" />

    <TextView

        android:id="@+id/txtCount"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"/>

    <TextView

        android:id="@+id/txt1"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

</LinearLayout>

package com.android.xiong.sharepreferencestest;

import java.text.SimpleDateFormat;

import java.util.Date;

import android.app.Activity;

import android.content.Context;

import android.content.SharedPreferences;

import android.content.SharedPreferences.Editor;

import android.os.Bundle;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

public class MainActivity extends Activity {

	private Button write;

	private Button read;

	private TextView txt1;

	private TextView countTxt;

	SharedPreferences share ;

	Editor editor;

	int countO=0;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		//获取SharedPreferences对象

		share = this.getSharedPreferences("share",

				Context.MODE_PRIVATE);

		//获取Editor对象

	    editor = share.edit();

		write = (Button) findViewById(R.id.write);

		read = (Button) findViewById(R.id.read);

		txt1 = (TextView) findViewById(R.id.txt1);

		countTxt=(TextView)findViewById(R.id.txtCount);

		//获取share中key为count的值

		countO=share.getInt("count", 0);

		countO++;

		//修改share中key为count的值

		editor.putInt("count", countO);

		//提交修改

		editor.commit();

		System.out.println("该应用程序使用了:"+countO+"次");

		countTxt.setText("该应用程序使用了:"+countO+"次");

		OnClickListener writeListener = new OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				SimpleDateFormat data = new SimpleDateFormat(

						"写入日期:yyyy年MM月dd日,时间:hh:mm:ss");

				editor.putString("time",

						data.format(new Date()));

				editor.commit();

			}

		};

		OnClickListener readListener=new OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				if(!share.contains("share")){

					txt1.setText(share.getString("time", null));

				}

			}

		};

		write.setOnClickListener(writeListener);

		read.setOnClickListener(readListener);

	}

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.main, menu);

		return true;

	}

}