blocks|key|1173989|text|您不能这样做:)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1173990|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

blocks|key|1174047|text|这需要Lollipop+(v5.0/API+21)或更高版本|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1174048|我的目标是通过一个服务来调整系统音量，所以这将只监听摇杆。然而，任何行动都可以在媒体上采取。|1174049|它将覆盖音量键操作，因此可能不需要全局使用它。|1174050|public+class+VolumeKeyController+{

++++private+MediaSessionCompat+mMediaSession;
++++private+final+Context+mContext;

++++public+VolumeKeyController(Context+context)+{
++++++++mContext+=+context;
++++}

++++private+void+createMediaSession()+{
++++++++mMediaSession+=+new+MediaSessionCompat(mContext,+KeyUtil.log);

++++++++mMediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS+%7C
++++++++++++++++MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);
++++++++mMediaSession.setPlaybackState(new+Builder()
++++++++++++++++.setState(PlaybackStateCompat.STATE_PLAYING,+0,+0)
++++++++++++++++.build());
++++++++mMediaSession.setPlaybackToRemote(getVolumeProvider());
++++++++mMediaSession.setActive(true);
++++}

++++private+VolumeProviderCompat+getVolumeProvider()+{
++++++++final+AudioManager+audio+=+(AudioManager)+mContext.getSystemService(Context.AUDIO_SERVICE);

++++++++int+STREAM_TYPE+=+AudioManager.STREAM_MUSIC;
++++++++int+currentVolume+=+audio.getStreamVolume(STREAM_TYPE);
++++++++int+maxVolume+=+audio.getStreamMaxVolume(STREAM_TYPE);

++++++++return+new+VolumeProviderCompat(VolumeProviderCompat.VOLUME_CONTROL_RELATIVE,+maxVolume,+currentVolume)+{
++++++++++++@Override
++++++++++++public+void+onAdjustVolume(int+direction)+{
++++++++++++++++//+Volume+Up+=+AudioManager.ADJUST_LOWER,+Volume+Down+=+AudioManager.ADJUST_LOWER,+Release+=+AudioManager.ADJUST_SAME
++++++++++++++++//+Replace+with+your+action,+if+you+don't+want+to+adjust+system+volume
++++++++++++++++if+(direction+==+AudioManager.ADJUST_RAISE)+{
++++++++++++++++++++audio.adjustStreamVolume(STREAM_TYPE,
++++++++++++++++++++++++++++AudioManager.ADJUST_RAISE,+AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
++++++++++++++++}
++++++++++++++++else+if+(direction+==+AudioManager.ADJUST_LOWER)+{
++++++++++++++++++++audio.adjustStreamVolume(STREAM_TYPE,
++++++++++++++++++++++++++++AudioManager.ADJUST_LOWER,+AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
++++++++++++++++}
++++++++++++++++setCurrentVolume(audio.getStreamVolume(STREAM_TYPE));
++++++++++++}
++++++++};
++++}

++++//+Call+when+control+needed,+add+a+call+to+constructor+if+needed+immediately
++++public+void+setActive(boolean+active)+{
++++++++if+(mMediaSession+!=+null)+{
++++++++++++mMediaSession.setActive(active);
++++++++++++return;
++++++++}
++++++++createMediaSession();
++++}

++++//+Call+from+Service's+onDestroy+method
++++public+void+destroy()+{
++++++++if+(mMediaSession+!=+null)+{
++++++++++++mMediaSession.release();
++++++++}
++++}
}|code-block|syntax|javascript|1174051|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<h1>This requires Lollipop (v5.0/API 21) or higher</h1>
My goal was to adjust system volume from a Service, so this will only listen for the rocker. Any action can be taken on press though.
It will override volume key action, so using it globally may not be desired.
<pre><code>public class VolumeKeyController {

 private MediaSessionCompat mMediaSession;
 private final Context mContext;

 public VolumeKeyController(Context context) {
 mContext = context;
 }

 private void createMediaSession() {
 mMediaSession = new MediaSessionCompat(mContext, KeyUtil.log);

 mMediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS |
 MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);
 mMediaSession.setPlaybackState(new Builder()
 .setState(PlaybackStateCompat.STATE_PLAYING, 0, 0)
 .build());
 mMediaSession.setPlaybackToRemote(getVolumeProvider());
 mMediaSession.setActive(true);
 }

 private VolumeProviderCompat getVolumeProvider() {
 final AudioManager audio = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);

 int STREAM_TYPE = AudioManager.STREAM_MUSIC;
 int currentVolume = audio.getStreamVolume(STREAM_TYPE);
 int maxVolume = audio.getStreamMaxVolume(STREAM_TYPE);

 return new VolumeProviderCompat(VolumeProviderCompat.VOLUME_CONTROL_RELATIVE, maxVolume, currentVolume) {
 @Override
 public void onAdjustVolume(int direction) {
 // Volume Up = AudioManager.ADJUST_LOWER, Volume Down = AudioManager.ADJUST_LOWER, Release = AudioManager.ADJUST_SAME
 // Replace with your action, if you don't want to adjust system volume
 if (direction == AudioManager.ADJUST_RAISE) {
 audio.adjustStreamVolume(STREAM_TYPE,
 AudioManager.ADJUST_RAISE, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
 }
 else if (direction == AudioManager.ADJUST_LOWER) {
 audio.adjustStreamVolume(STREAM_TYPE,
 AudioManager.ADJUST_LOWER, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
 }
 setCurrentVolume(audio.getStreamVolume(STREAM_TYPE));
 }
 };
 }

 // Call when control needed, add a call to constructor if needed immediately
 public void setActive(boolean active) {
 if (mMediaSession != null) {
 mMediaSession.setActive(active);
 return;
 }
 createMediaSession();
 }

 // Call from Service's onDestroy method
 public void destroy() {
 if (mMediaSession != null) {
 mMediaSession.release();
 }
 }
}
</code></pre>

What I'm basically trying to achieve is custom global hot keys or in other words 'things will happen when I push certain buttons no matter which program is currently on top'. 
I assume a service is needed.

I have a quick and dirty test that just tells me what has been pressed that will work if it is the active window.

<pre><code>public boolean onKeyDown(int keyCode, KeyEvent event) {
 char pop;
 pop = (char)event.getUnicodeChar();
 Toast.makeText(this, Character.toString(pop) , Toast.LENGTH_SHORT).show();
 return super.onKeyDown(keyCode, event);
 }
</code></pre>

But obviously if I change window or go into a text box it doesn't work. If I stick it directly into a service (or an imputmethodservice) and launch said service nothing happens. (Some permissions required maybe?)
Any suggestions where I'm going wrong? Or a better way of capturing which button is pressed?

Thanks!

onKeyDown in a service? (Global Hot Keys)

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我基本上想实现的是自定义全局热键，或者换句话说，“当我按下特定的按钮时，无论当前哪个程序在顶部，都会发生一些事情”。我假设需要一个服务。我有一个快速而肮脏的测试，它只是告诉我，如果它是活动窗口，那么按下的是什么就可以工作。public boolean onKeyDown(int keyCode, KeyEvent ev...

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