Android监听Home键和Back键的区别介绍
一：Android中Home键监听和Back键监听的区别：
(1).在Android中，当按下Home键的时候，默认情况下Stop前台的Activity，即Activity设置成停止状态【onStop()】，而不是销毁状态【onDestory()】。如果再次启动该Activity，不是调用onCreate()方法，而是调用onSavedInstanceState方法。则是从onRestart()开始-onStart()-onResume()。
(2).当按下back键则不同，back键默认finish前台的activity，即activity的状态为onDestory为止，再次启动该activity则从onCreate开始，不会调用onSavedInstanceState方法。
总而言之：按下Home键会返回桌面，而back则会返回前一个activity。
在这里Back键的实现方法就不赘述了，主要讲解一下Home键的实现方式吧。以下是我找的参考资料自己思考的。请大家给出建议。
Home键监听的实现方法：
(1).在onResum里面注册广播，OnPause里面注销广播。
(2).在广播中拦截Intent.ACTION_CLOSE_SYSTEM_DIALOGS这个Action，通过获取Reason字段来判断长按还是单击Home键。
代码如下：
(1).Home键监听封装类：
packagecom.scd.homewatcher.util;
importandroid.content.BroadcastReceiver;
importandroid.content.Context;
importandroid.content.Intent;
importandroid.content.IntentFilter;
importandroid.util.Log;
/**
*Home键监听封装
*
*@authorway
*
*/
publicclassHomeWatcher{
//回调接口
publicinterfaceOnHomePressedListener{
publicvoidonHomePressed();
publicvoidonHomeLongPressed();
}
privatestaticfinalStringTAG="HomeWatcher";
/**上下文*/
privateContextmContext;
/**过滤器*/
privateIntentFiltermFilter;
/**接口*/
privateOnHomePressedListenermListener;
/**广播接收者*/
privateInnerReceviermRecevier;
publicHomeWatcher(Contextcontext){
mContext=context;
mRecevier=newInnerRecevier();
mFilter=newIntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
}
/**
*设置监听
*
*@paramlistener
*/
publicvoidsetOnHomePressedListener(OnHomePressedListenerlistener){
mListener=listener;
}
/**
*开始监听，注册广播
*/
publicvoidstartWatch(){
if(mRecevier!=null){
mContext.registerReceiver(mRecevier,mFilter);
}
}
/**
*停止监听，注销广播
*/
publicvoidstopWatch(){
if(mRecevier!=null){
mContext.unregisterReceiver(mRecevier);
}
}
/**
*广播接收者
*/
privateclassInnerRecevierextendsBroadcastReceiver{
finalStringSYSTEM_DIALOG_REASON_KEY="reason";
finalStringSYSTEM_DIALOG_REASON_GLOBAL_ACTIONS="globalactions";
finalStringSYSTEM_DIALOG_REASON_RECENT_APPS="recentapps";
finalStringSYSTEM_DIALOG_REASON_HOME_KEY="homekey";
@Override
publicvoidonReceive(Contextcontext,Intentintent){
Stringaction=intent.getAction();
if(action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)){
Stringreason=intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
if(reason!=null){
Log.i(TAG,"action:"+action+",reason:"+reason);
if(mListener!=null){
if(reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)){
//短按home键
mListener.onHomePressed();
}elseif(reason
.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)){
//长按home键
mListener.onHomeLongPressed();
}
}
}
}
}
}
}
(2).MainActivity类：
packagecom.scd.homewatcher;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.view.KeyEvent;
importandroid.widget.Toast;
importcom.scd.homewatcher.util.HomeWatcher;
importcom.scd.homewatcher.util.HomeWatcher.OnHomePressedListener;
publicclassMainActivityextendsActivityimplementsOnHomePressedListener{
privateHomeWatchermHomeWatcher;
@Override
protectedvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
protectedvoidonResume(){
mHomeWatcher=newHomeWatcher(this);
mHomeWatcher.setOnHomePressedListener(this);
//注册广播
mHomeWatcher.startWatch();
super.onResume();
}
@Override
protectedvoidonPause(){
mHomeWatcher.setOnHomePressedListener(null);
//注销广播
mHomeWatcher.stopWatch();
super.onPause();
}
@Override
publicvoidonHomePressed(){
//TODO
Toast.makeText(this,"短按Home键,实现自己的逻辑",Toast.LENGTH_SHORT).show();
}
@Override
publicvoidonHomeLongPressed(){
//TODO
Toast.makeText(this,"长按Home键,实现自己的逻辑",Toast.LENGTH_SHORT).show();
}
@Override
publicbooleanonKeyDown(intkeyCode,KeyEventevent){
if((keyCode==KeyEvent.KEYCODE_BACK)){
System.out.println("按下了back键onKeyDown()");
returnfalse;
}else{
returnsuper.onKeyDown(keyCode,event);
}
}
@Override
publicvoidonBackPressed(){
//super.onBackPressed()会自动调用finish()方法,关闭
super.onBackPressed();
}
}