Android Back Home键监听
Back键的监听
对于Back键的监听比较容易,可以在多个系统回调处拦截,比如在activity的下列方法中都可以收到Back键按下的事件:
@Override
public void onBackPressed() {
// super.onBackPressed();//注释掉这行,back键不退出activity Log.i(LOG_TAG, "onBackPressed");
} @Override
public boolean dispatchKeyEvent(KeyEvent event) {
Log.i(LOG_TAG, "dispatchKeyEvent: keyCode -- " + event.getKeyCode());
return super.dispatchKeyEvent(event);
} @Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
Log.i(LOG_TAG, "onKeyDown: keyCode -- " + keyCode); switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
Log.i(LOG_TAG, "KeyEvent.KEYCODE_BACK");
break;
case KeyEvent.KEYCODE_MENU:
Log.i(LOG_TAG, "KeyEvent.KEYCODE_MENU");
break;
case KeyEvent.KEYCODE_HOME:
Log.i(LOG_TAG, "KeyEvent.KEYCODE_HOME");
// 收不到
break;
case KeyEvent.KEYCODE_APP_SWITCH:
Log.i(LOG_TAG, "KeyEvent.KEYCODE_APP_SWITCH");
// 收不到
break;
default:
break;
} return super.onKeyDown(keyCode, event); }
Home键的广播监听
对于Home键的监听不是那么容易,因为Home键可以将程序退出放在后台,所以这个事件是直接分发给系统,系统接收到之后做相应处理,Home键的事件不是直接传递到应用里面.所以在上述监听Back键的代码中,相应的回调中是收不到Home键的事件的.
参考文后的博客链接,对Home键的监听主要通过注册广播接收器实现,拦截让窗口关闭的系统动作,然后根据Intent里面的具体参数,分析当前到底是Home键, 应用切换键,还是其他功能按键.
接收器实现如下:
package com.mengdd.hellohome; import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log; public class HomeWatcherReceiver extends BroadcastReceiver {
private static final String LOG_TAG = "HomeReceiver";
private static final String SYSTEM_DIALOG_REASON_KEY = "reason";
private static final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
private static final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";
private static final String SYSTEM_DIALOG_REASON_LOCK = "lock";
private static final String SYSTEM_DIALOG_REASON_ASSIST = "assist"; @Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
Log.i(LOG_TAG, "onReceive: action: " + action);
if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
// android.intent.action.CLOSE_SYSTEM_DIALOGS
String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
Log.i(LOG_TAG, "reason: " + reason); if (SYSTEM_DIALOG_REASON_HOME_KEY.equals(reason)) {
// 短按Home键
Log.i(LOG_TAG, "homekey"); }
else if (SYSTEM_DIALOG_REASON_RECENT_APPS.equals(reason)) {
// 长按Home键 或者 activity切换键
Log.i(LOG_TAG, "long press home key or activity switch"); }
else if (SYSTEM_DIALOG_REASON_LOCK.equals(reason)) {
// 锁屏
Log.i(LOG_TAG, "lock");
}
else if (SYSTEM_DIALOG_REASON_ASSIST.equals(reason)) {
// samsung 长按Home键
Log.i(LOG_TAG, "assist");
} }
} }
注意不同手机的按键不同,所以需要对不同理由做区分.
Home键监听广播注册
广播接收器的注册有两种方式,一种是静态注册,即写在manifest里面声明;另一种是动态注册,即在Java代码里面注册.
上面对Home键实现监听的这个receiver,静态注册如下:
<receiver android:name="com.mengdd.hellohome.HomeWatcherReceiver" >
<intent-filter>
<action android:name="android.intent.action.CLOSE_SYSTEM_DIALOGS" />
</intent-filter>
</receiver>
但是发现静态注册不起作用,即收不到onReceive回调.
采用动态注册:
private static HomeWatcherReceiver mHomeKeyReceiver = null;
private static void registerHomeKeyReceiver(Context context) {
Log.i(LOG_TAG, "registerHomeKeyReceiver");
mHomeKeyReceiver = new HomeWatcherReceiver();
final IntentFilter homeFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
context.registerReceiver(mHomeKeyReceiver, homeFilter);
}
private static void unregisterHomeKeyReceiver(Context context) {
Log.i(LOG_TAG, "unregisterHomeKeyReceiver");
if (null != mHomeKeyReceiver) {
context.unregisterReceiver(mHomeKeyReceiver);
}
}
在Activity的onResume和onPause里面分别调用:
@Override
protected void onResume() {
super.onResume(); registerHomeKeyReceiver(this);
} @Override
protected void onPause() { unregisterHomeKeyReceiver(this);
super.onPause();
}
当然也可以根据需要在其他合适的时机注册和注销.