按Back key把Activity关掉即使有键盘的时候
一般情况下，当键盘显示的时候，你按下back只会将键盘关掉，但有时候你想要不仅仅是把键盘关掉而已，还想把当前的activity/给关掉。那你可以重写你的activity的main view,下面的例子是我看QucikSearchBox ap中SearchActivityView.java。
/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.android.quicksearchbox.ui;import android.app.Activity;import android.content.Context;import android.util.AttributeSet;import android.view.KeyEvent;import android.view.inputmethod.InputMethodManager;import android.widget.RelativeLayout;/** * Finishes the containing activity on BACK, even if input method is showing. */public class SearchActivityView extends RelativeLayout { public SearchActivityView(Context context) { super(context); } public SearchActivityView(Context context, AttributeSet attrs) { super(context, attrs); } public SearchActivityView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } private Activity getActivity() { Context context = getContext(); if (context instanceof Activity) { return (Activity) context; } else { return null; } } /** * Hides the input method. */ protected void hideInputMethod() { InputMethodManager imm = (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE); if (imm != null) { imm.hideSoftInputFromWindow(getWindowToken(), 0); } } /** * Overrides the handling of the back key to dismiss the activity. */ @Override public boolean dispatchKeyEventPreIme(KeyEvent event) { Activity activity = getActivity(); if (activity != null && event.getKeyCode() == KeyEvent.KEYCODE_BACK) { KeyEvent.DispatcherState state = getKeyDispatcherState(); if (state != null) { if (event.getAction() == KeyEvent.ACTION_DOWN && event.getRepeatCount() == 0) { state.startTracking(event, this); return true; } else if (event.getAction() == KeyEvent.ACTION_UP && !event.isCanceled() && state.isTracking(event)) { hideInputMethod(); activity.onBackPressed(); return true; } } } return super.dispatchKeyEventPreIme(event); }}