Android开发实现的内存管理工具类

public class MemoryManager {  private static final String TAG = "MemoryManager";  private static final int MAXMEMORY=300*1024*1024;//程序运行的最大内存 模拟器(0-16m)    public static boolean hasAcailMemory() {    // 获取手机内部空间大小    long memory = getAvailableInternalMemorySize();    Log.i(TAG, memory+"");    if (memory < MAXMEMORY) {      //应用将处于低内存状态下运行      return false;    } else {      return true;    }  }    @SuppressWarnings("deprecation")  public static long getAvailableInternalMemorySize() {    File path = Environment.getDataDirectory();// 获取 Android 数据目录    StatFs stat = new StatFs(path.getPath());// 一个模拟linux的df命令的一个类,获得SD卡和手机内存的使用情况    long blockSize = stat.getBlockSize();// 返回 Int ，大小，以字节为单位，一个文件系统    long availableBlocks = stat.getAvailableBlocks();// 返回 Int ，获取当前可用的存储空间    return availableBlocks * blockSize;  }    @SuppressWarnings("deprecation")  public static long getTotalInternalMemorySize() {    File path = Environment.getDataDirectory();    StatFs stat = new StatFs(path.getPath());    long blockSize = stat.getBlockSize();    long totalBlocks = stat.getBlockCount();// 获取该区域可用的文件系统数    return totalBlocks * blockSize;  }    @SuppressWarnings("deprecation")  public static long getAvailableExternalMemorySize() {    if (externalMemoryAvailable()) {      File path = Environment.getExternalStorageDirectory();      StatFs stat = new StatFs(path.getPath());      long blockSize = stat.getBlockSize();      long availableBlocks = stat.getAvailableBlocks();      return availableBlocks * blockSize;    } else {      throw new RuntimeException("Don't have sdcard.");    }  }    @SuppressWarnings("deprecation")  public static long getTotalExternalMemorySize() {    if (externalMemoryAvailable()) {      File path = Environment.getExternalStorageDirectory();// 获取外部存储目录即 SDCard      StatFs stat = new StatFs(path.getPath());      long blockSize = stat.getBlockSize();      long totalBlocks = stat.getBlockCount();      return totalBlocks * blockSize;    } else {      throw new RuntimeException("Don't have sdcard.");    }  }    public static boolean externalMemoryAvailable() {    return android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);  }}