Android内存使用情况的应用实例

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 package="com.itheima28.memorydemo"
 android:versioncode="1"
 android:versionname="1.0" >
 
 <uses-sdk
  android:minsdkversion="8"
  android:targetsdkversion="19" />
    
 <application
  android:allowbackup="true"
  android:icon="@drawable/ic_launcher"
  android:label="@string/app_name"
  android:theme="@style/apptheme" >
  <activity
   android:name="com.itheima28.memorydemo.mainactivity"
   android:label="@string/app_name" >
   <intent-filter>
    <action android:name="android.intent.action.main" />
 
    <category android:name="android.intent.category.launcher" />
   </intent-filter>
  </activity>
 </application>
 
</manifest>

<relativelayout 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.itheima28.memorydemo.mainactivity$placeholderfragment" >
 
 <textview
  android:id="@+id/tv_memory_info"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_centerinparent="true"/>
 
</relativelayout>

package com.itheima28.memorydemo;
 
import java.io.file;
 
import android.os.bundle;
import android.os.environment;
import android.os.statfs;
import android.support.v7.app.actionbaractivity;
import android.text.format.formatter;
import android.widget.textview;
 
public class mainactivity extends actionbaractivity {
 
 @override
 protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_main);
  
  textview tvmemoryinfo = (textview) findviewbyid(r.id.tv_memory_info);
  
  //获得sd卡的内存状态
  file sdcardfiledir = environment.getexternalstoragedirectory();
  string sdcardmemory = getmemoryinfo(sdcardfiledir);
 
  //获得手机内部存储控件的状态
  file datafiledir = environment.getdatadirectory();
  string datamemory = getmemoryinfo(datafiledir);
 
  tvmemoryinfo.settext("sd卡: " + sdcardmemory + "\n手机内部: " + datamemory);
 }
 
 /**
  * 根据路径获取内存状态
  * @param path
  * @return
  */
 @suppresswarnings("deprecation")
 private string getmemoryinfo(file path) {
  //获得一个磁盘状态对象
  statfs stat = new statfs(path.getpath());
  
  //获得一个扇区的大小
  long blocksize = stat.getblocksize();
 
  //获得扇区的总数
  long totalblocks = stat.getblockcount();
  
  //获得可用的扇区数量
  long availableblocks = stat.getavailableblocks();
 
  //总空间
  string totalmemory = formatter.formatfilesize(this, totalblocks * blocksize);
  
  //可用空间
  string availablememory = formatter.formatfilesize(this, availableblocks * blocksize);
  
  return "总空间：" + totalmemory + "\n可用空间：" + availablememory;
 }
}