Android Back Home鍵監聽
阿新 • • 發佈：2018-11-17
Android Back Home鍵監聽
Android Back Home鍵監聽
Back鍵的監聽
對於Back鍵的監聽比較容易,可以在多個系統回撥處攔截,比如在activity的下列方法中都可以收到Back鍵按下的事件:
@Override public void onBackPressed() { // super.onBackPressed();//註釋掉這行,back鍵不退出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鍵的廣播監聽
對於Home鍵的監聽不是那麼容易,因為Home鍵可以將程式退出放在後臺,所以這個事件是直接分發給系統,系統接收到之後做相應處理,Home鍵的事件不是直接傳遞到應用裡面.所以在上述監聽Back鍵的程式碼中,相應的回撥中是收不到Home鍵的事件的.
參考文後的部落格連結,對Home鍵的監聽主要通過註冊廣播接收器實現,攔截讓視窗關閉的系統動作,然後根據Intent裡面的具體引數,分析當前到底是Home鍵, 應用切換鍵,還是其他功能按鍵.
接收器實現如下:
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鍵 Log.i(LOG_TAG, "homekey"); } else if (SYSTEM_DIALOG_REASON_RECENT_APPS.equals(reason)) { // 長按Home鍵 或者 activity切換鍵 Log.i(LOG_TAG, "long press home key or activity switch"); } else if (SYSTEM_DIALOG_REASON_LOCK.equals(reason)) { // 鎖屏 Log.i(LOG_TAG, "lock"); } else if (SYSTEM_DIALOG_REASON_ASSIST.equals(reason)) { // samsung 長按Home鍵 Log.i(LOG_TAG, "assist"); } } } }
注意不同手機的按鍵不同,所以需要對不同理由做區分.
Home鍵監聽廣播註冊
廣播接收器的註冊有兩種方式,一種是靜態註冊,即寫在manifest裡面宣告;另一種是動態註冊,即在Java程式碼裡面註冊.
上面對Home鍵實現監聽的這個receiver,靜態註冊如下:
<receiver android:name="com.mengdd.hellohome.HomeWatcherReceiver" > <intent-filter> <action android:name="android.intent.action.CLOSE_SYSTEM_DIALOGS" /> </intent-filter> </receiver>
但是發現靜態註冊不起作用,即收不到onReceive回撥.
採用動態註冊:
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裡面分別呼叫:
@Override
protected void onResume() {
super.onResume();
registerHomeKeyReceiver(this);
}
@Override
protected void onPause() {
unregisterHomeKeyReceiver(this);
super.onPause();
}
當然也可以根據需要在其他合適的時機註冊和登出.