public class MemoryManager extends Manager {
    private ActivityManager mActivityManager;

    public MemoryManager(Config config) {
        super(config);

        //获得ActivityManager服务的对象。
        mActivityManager = (ActivityManager) SDKUtil.getAppContext().getSystemService(Context.ACTIVITY_SERVICE);
    }

    public ActivityManager.MemoryInfo getMemoryInfo() {
        //获得MemoryInfo对象。
        ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();

        //获得系统可用内存，保存在MemoryInfo对象上。
        mActivityManager.getMemoryInfo(memoryInfo);

        return memoryInfo;
    }

    /**
     * 获取进程最大物理内存。
     * 系统为应用分配的内存，没有额外的扩充。
     *
     * @return
     */
    public int getMemoryClass() {
        return mActivityManager.getMemoryClass();
    }

    /**
     * 在Android 3.0之后，manifest支持largeheap选项，设置为true后可以为应用申请分配更多内存。
     * 开发者通过设置manifest文件中的<application>标签中largeHeap属性的值为"true"，获得应用可使用的最大内存。
     *
     * @return
     */
    public int getLargeMemoryClass() {
        return mActivityManager.getLargeMemoryClass();
    }

    /**
     * Returns the size of the native heap.
     *
     * @return The size of the native heap in bytes.
     */
    public long getNativeHeapSize() {
        return android.os.Debug.getNativeHeapSize();
    }

    /**
     * Returns the amount of allocated memory in the native heap.
     *
     * @return The allocated size in bytes.
     */
    public long getNativeHeapAllocatedSize() {
        return android.os.Debug.getNativeHeapAllocatedSize();
    }

    /**
     * Returns the amount of free memory in the native heap.
     *
     * @return The freed size in bytes.
     */
    public long getNativeHeapFreeSize() {
        return android.os.Debug.getNativeHeapFreeSize();
    }

    /**
     * Returns the maximum amount of memory that the Java virtual machine will
     * attempt to use.  If there is no inherent limit then the value {@link
     * java.lang.Long#MAX_VALUE} will be returned.
     *
     * @return the maximum amount of memory that the virtual machine will
     * attempt to use, measured in bytes
     */
    public long maxMemory() {
        return Runtime.getRuntime().maxMemory();
    }
}