Fragment中监听返回键处理

当前的Fragment实现监听接口:
implements OnKeyDownListenter

public interface OnKeyDownListenter {
    /**
     * 键盘按钮按键处理
     * 
     * @param keyCode
     * @param event
     * @return true 已执行处理 false 未执行
     */
    public boolean onKeyDown(int keyCode, KeyEvent event);
}

当前Fragment:

 private void init() {
        ((getActivity())).setOnAcitivityCallback(this);
    }
ondestory时候
 homePageActivity.removeCallbackListener();

当前Fragment:

   @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
            //要做的事情
            XXXX
            return true;
        }
        return false;
    }

Activity里面:

    private OnKeyDownListenter mDoneCallback = null;// Fragmet操作 回调对象

 @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
              if (mDoneCallback != null && mDoneCallback.onKeyDown(keyCode, event)) {
            return true;
        }
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
            if ((System.currentTimeMillis() - mExitTime) > 2000) {
                mExitTime = System.currentTimeMillis();
            } else {
                finish();
            }
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
@Override
    public void removeCallbackListener() {
        this.mDoneCallback = null;
    }