android释放内存的一个办法

step 1:定义一个监听接口

public static interface OnLowMemoryListener {  
        void onLowMemoryReceived();  
    }  /* 何问起 hovertree.com */

step 2:android application文件中添加如下代码

//初始化

private ArrayList<WeakReference<OnLowMemoryListener>> mLowMemoryListeners;  
/* 何问起 hovertree.com */

public MyApp() {  
        mLowMemoryListeners = new ArrayList<WeakReference<OnLowMemoryListener>>();  
    }  /* 何问起 hovertree.com */

//注册监听

public void registerOnLowMemoryListener(OnLowMemoryListener listener) {  
        if (listener != null) {  
            mLowMemoryListeners  
                    .add(new WeakReference<MyApp.OnLowMemoryListener>(listener));  
        }  
    }  
//移除监听  
    public void unregisterOnLowMemoryListener(OnLowMemoryListener listener) {  
        if (listener != null) {  
            int i = 0;  
            while (i < mLowMemoryListeners.size()) {  
                final OnLowMemoryListener l = mLowMemoryListeners.get(i).get();  
                if (l == null || l == listener) {  
                    mLowMemoryListeners.remove(i);  
                } else {  
                    i++;  
                }  
            }  
        }  
    }  /* 何问起 hovertree.com */

//内存空间过低的时候，被系统调用

@Override  
    public void onLowMemory() {  
        super.onLowMemory();  
        int i = 0;  
        while (i < mLowMemoryListeners.size()) {  
            final OnLowMemoryListener l = mLowMemoryListeners.get(i).get();  
            if (l == null) {  
                mLowMemoryListeners.remove(i);  
            } else {  
                l.onLowMemoryReceived();  
                i++;  
            }  
        }  
    }  /* 何问起 hovertree.com */

step 3：那些浪费内存的地方，比如图片缓存，可以实现并注册这个监听

推荐:http://www.cnblogs.com/roucheng/p/androidtuichu.html