原文：http://www.cnblogs.com/newcj/articles/2066337.html

public void onAttachedToWindow()
{  
       this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);     
       super.onAttachedToWindow(); 	
}

在activity中加上这段代码就可以屏蔽home，至于为什么，因为android系统自己对与home键power键在PhoneWindowManager中做了处理，不会返回到上层应用的，但是我在看这部分代码的时候看到：

\frameworks\policies\base\phone\com\android\internal\policy\impl\PhoneWindowManager.java 1089行
 
if (code == KeyEvent.KEYCODE_HOME) {
 
            // If a system window has focus, then it doesn't make sense
            // right now to interact with applications.
            WindowManager.LayoutParams attrs = win != null ? win.getAttrs() : null;
            if (attrs != null) {
                final int type = attrs.type;
                if (type == WindowManager.LayoutParams.TYPE_KEYGUARD
                        || type == WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG) {
                    // the "app" is keyguard, so give it the key
                    return false;
                }
                final int typeCount = WINDOW_TYPES_WHERE_HOME_DOESNT_WORK.length;
                for (int i=0; i<typeCount; i++) {
                    if (type == WINDOW_TYPES_WHERE_HOME_DOESNT_WORK[i]) {
                        // don't do anything, but also don't pass it to the app
                        return true;
                    }
                }
            }

type == WindowManager.LayoutParams.TYPE_KEYGUARD这一句，我们可以看到，android对于锁屏特殊判断了，所以我就模拟这个进行的实现，只是有一点，activity中重写onAttachedToWindow（）方法需要api 5以上。