Back键和Home键监听

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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:

复制代码
    @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);    }
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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:

复制代码
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");            }        }    }}
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  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:

复制代码
    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);        }    }
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  在Activity的onResume和onPause里面分别调用:

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    @Override    protected void onResume() {        super.onResume();        registerHomeKeyReceiver(this);    }    @Override    protected void onPause() {        unregisterHomeKeyReceiver(this);        super.onPause();    }
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  当然也可以根据需要在其他合适的时机注册和注销.

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:


复制代码
@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);

}

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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:


复制代码
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");
}

}
}

}

复制代码

  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:


复制代码
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);
}
}

复制代码

  

  在Activity的onResume和onPause里面分别调用:


复制代码
@Override
protected void onResume() {
super.onResume();

registerHomeKeyReceiver(this);
}

@Override
protected void onPause() {

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

复制代码

  当然也可以根据需要在其他合适的时机注册和注销.

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