android HOME鍵的監聽

Back鍵的監聽

　　對於Back鍵的監聽比較容易,能夠在多個系統回調處攔截,好比在activity的下列方法中均可以收到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,由於Home鍵能夠將程序退出放在後臺,因此這個事件是直接分發給系統,系統接收到以後作相應處理,Home鍵的事件不是直接傳遞到應用裏面.因此在上述監聽Back鍵的代碼中,相應的回調中是收不到Home鍵的事件的.

　　參考文後的博客連接,對Home鍵的監聽主要經過註冊廣播接收器實現,攔截讓窗口關閉的系統動做,而後根據Intent裏面的具體參數,分析當前究竟是Home鍵, 應用切換鍵,仍是其餘功能按鍵.

　　接收器實現以下:

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");
            }

        }
    }

}

　　注意不一樣手機的按鍵不一樣,因此須要對不一樣理由作區分.

 

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裏面聲明;另外一種是動態註冊,即在Java代碼裏面註冊.

　　上面對Home鍵實現監聽的這個receiver,靜態註冊以下:

     <receiver android:name="com.mengdd.hellohome.HomeWatcherReceiver" >
           <intent-filter>
               <action android:name="android.intent.action.CLOSE_SYSTEM_DIALOGS" />
           </intent-filter>
       </receiver>

　　可是發現靜態註冊不起做用,即收不到onReceive回調.

 

　　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裏面分別調用:

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

        registerHomeKeyReceiver(this);
    }

    @Override
    protected void onPause() {

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

　　固然也能夠根據須要在其餘合適的時機註冊和註銷.