Android 如何获取手机总内存和可用内存等信息

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:orientation="vertical" 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" > 
<TextView  
  android:layout_width="fill_parent"  
  android:layout_height="wrap_content"  
  android:textStyle="bold" 
  android:id="@+id/system_memory" /> 
</LinearLayout> 

package com.figo.readsyememory; 
 
import android.app.Activity; 
import android.os.Bundle; 
import java.io.BufferedReader; 
import java.io.FileReader; 
import java.io.IOException; 
import android.app.ActivityManager; 
import android.app.ActivityManager.MemoryInfo; 
import android.content.Context; 
import android.text.format.Formatter; 
import android.util.Log; 
import android.widget.TextView; 
 
public class ReadSystemMemory extends Activity { 
 
  TextView tv = null; 
 
  private String getAvailMemory() {// 获取android当前可用内存大小 
 
    ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE); 
    MemoryInfo mi = new MemoryInfo(); 
    am.getMemoryInfo(mi); 
    //mi.availMem; 当前系统的可用内存 
 
    return Formatter.formatFileSize(getBaseContext(), mi.availMem);// 将获取的内存大小规格化 
  } 
 
  private String getTotalMemory() { 
    String str1 = "/proc/meminfo";// 系统内存信息文件 
    String str2; 
    String[] arrayOfString; 
    long initial_memory = 0; 
 
    try { 
      FileReader localFileReader = new FileReader(str1); 
      BufferedReader localBufferedReader = new BufferedReader( 
          localFileReader, 8192); 
      str2 = localBufferedReader.readLine();// 读取meminfo第一行，系统总内存大小 
 
      arrayOfString = str2.split("\\s+"); 
      for (String num : arrayOfString) { 
        Log.i(str2, num + "\t"); 
      } 
 
      initial_memory = Integer.valueOf(arrayOfString[1]).intValue() * 1024;// 获得系统总内存，单位是KB，乘以1024转换为Byte 
      localBufferedReader.close(); 
 
    } catch (IOException e) { 
    } 
    return Formatter.formatFileSize(getBaseContext(), initial_memory);// Byte转换为KB或者MB，内存大小规格化 
  } 
 
  /** Called when the activity is first created. */ 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
 
    tv = (TextView) findViewById(R.id.system_memory); 
    tv.setText("手机总内存: " + this.getTotalMemory() + ", " + "可用内存: " 
        + this.getAvailMemory()); 
  } 
} 

public class GetFreeMem extends Activity { 
  /** Called when the activity is first created. */ 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    Method _readProclines = null; 
    try { 
      Class procClass; 
      procClass = Class.forName("android.os.Process"); 
      Class parameterTypes[]= new Class[] {String.class, String[].class, long[].class }; 
      _readProclines = procClass.getMethod("readProcLines", parameterTypes); 
      Object arglist[] = new Object[3]; 
      final String[] mMemInfoFields = new String[] {"MemTotal:", 
          "MemFree:", "Buffers:", "Cached:"}; 
      long[] mMemInfoSizes = new long[mMemInfoFields.length]; 
      mMemInfoSizes[0] = 30; 
      mMemInfoSizes[1] = -30; 
      arglist[0] = new String("/proc/meminfo"); 
      arglist[1] = mMemInfoFields; 
      arglist[2] = mMemInfoSizes; 
      if(_readProclines!=null){ 
        _readProclines.invoke(null, arglist); 
        for (int i=0; i<mMemInfoSizes.length; i++) { 
          Log.d("GetFreeMem", mMemInfoFields[i]+" : "+mMemInfoSizes[i]/1024); 
        } 
      } 
    } catch (ClassNotFoundException e) { 
      e.printStackTrace(); 
    } catch (SecurityException e) { 
      e.printStackTrace(); 
    } catch (IllegalArgumentException e) { 
      e.printStackTrace(); 
    } catch (IllegalAccessException e) { 
      e.printStackTrace(); 
    } catch (InvocationTargetException e) { 
      e.printStackTrace(); 
    } catch (NoSuchMethodException e) { 
      e.printStackTrace(); 
    } 
  } 
}