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Back鍵的監(jiān)聽(tīng)

　　對(duì)于Back鍵的監(jiān)聽(tīng)比較容易,可以在多個(gè)系統(tǒng)回調(diào)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();//注釋掉這行,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(jiān)聽(tīng)

　　對(duì)于Home鍵的監(jiān)聽(tīng)不是那么容易,因?yàn)镠ome鍵可以將程序退出放在后臺(tái),所以這個(gè)事件是直接分發(fā)給系統(tǒng),系統(tǒng)接收到之后做相應(yīng)處理,Home鍵的事件不是直接傳遞到應(yīng)用里面.所以在上述監(jiān)聽(tīng)Back鍵的代碼中,相應(yīng)的回調(diào)中是收不到Home鍵的事件的.

　　參考文后的博客鏈接,對(duì)Home鍵的監(jiān)聽(tīng)主要通過(guò)注冊(cè)廣播接收器實(shí)現(xiàn),攔截讓窗口關(guān)閉的系統(tǒng)動(dòng)作,然后根據(jù)Intent里面的具體參數(shù),分析當(dāng)前到底是Home鍵, 應(yīng)用切換鍵,還是其他功能按鍵.

　　接收器實(shí)現(xiàn)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(zhǎng)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(zhǎng)按Home鍵
??????????????? Log.i(LOG_TAG, "assist");
??????????? }

??????? }
??? }

}

　　注意不同手機(jī)的按鍵不同,所以需要對(duì)不同理由做區(qū)分.

?

Home鍵監(jiān)聽(tīng)廣播注冊(cè)

　　廣播接收器的注冊(cè)有兩種方式,一種是靜態(tài)注冊(cè),即寫(xiě)在manifest里面聲明;另一種是動(dòng)態(tài)注冊(cè),即在Java代碼里面注冊(cè).

　　上面對(duì)Home鍵實(shí)現(xiàn)監(jiān)聽(tīng)的這個(gè)receiver,靜態(tài)注冊(cè)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(fā)現(xiàn)靜態(tài)注冊(cè)不起作用,即收不到onReceive回調(diào).

?

　　采用動(dòng)態(tài)注冊(cè):

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里面分別調(diào)用:

@Override
??? protected void onResume() {
??????? super.onResume();

??????? registerHomeKeyReceiver(this);
??? }

??? @Override
??? protected void onPause() {

??????? unregisterHomeKeyReceiver(this);
??????? super.onPause();
??? }

　　當(dāng)然也可以根據(jù)需要在其他合適的時(shí)機(jī)注冊(cè)和注銷(xiāo).

轉(zhuǎn)載于:https://my.oschina.net/u/579890/blog/372409

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