public static final int FLAG_HOMEKEY_DISPATCHED = 0x80000000;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.getWindow().setFlags(FLAG_HOMEKEY_DISPATCHED, FLAG_HOMEKEY_DISPATCHED);//关键代码
        setContentView(R.layout.main);
    }
    再重写onKey事件即可。