在导航栏中添加音量加减button

一些Android音量调节button。或者从保护实体按键的角度考虑，就须要在导航栏的虚拟按键中加入音量加减调节按键。

效果例如以下图所看到的：

实现步骤例如以下：

1.首先在SystemUI中加入音量加减的资源文件。路径例如以下：

frameworks/base/packages/SystemUI/res/

将图片放入相应的drawable目录，包含音量+。和音量-，见上图。

2.改动导航栏的布局文件。路径：

frameworks/base/packages/SystemUI/res/

在相应的layout目录中找到navigation_bar.xml文件进行改动：

在返回键前面加入“音量减”。返回键的布局：

<com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/back"                android:layout_width="128dp" android:paddingStart="25dp" android:paddingEnd="25dp"                android:layout_height="match_parent"                android:src="@drawable/ic_sysbar_back"                systemui:keyCode="4"                android:layout_weight="0"                systemui:glowBackground="@drawable/ic_sysbar_highlight"                android:contentDescription="@string/accessibility_back"                />

音量减的布局例如以下。这里先把Visibility定义为Gone，然后在代码中控制是否显示：

<com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/sub"                android:src="@drawable/sub_normal"                android:layout_width="@dimen/navigation_key_width"                android:layout_height="match_parent"                android:layout_weight="0"                systemui:keyCode="302"                systemui:glowBackground="@drawable/ic_sysbar_highlight"                android:visibility="gone"/>  

“音量加”加入到“近期应用”之后，近期应用的布局：

<com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/recent_apps"                android:layout_width="128dp" android:paddingStart="25dp" android:paddingEnd="25dp"                android:layout_height="match_parent"                android:src="@drawable/ic_sysbar_recent"                android:layout_weight="0"                systemui:glowBackground="@drawable/ic_sysbar_highlight"                android:contentDescription="@string/accessibility_recent"                />

音量加的布局：

<com.android.systemui.statusbar.policy.KeyButtonView android:id="@+id/add"                android:src="@drawable/add_normal"                android:layout_width="@dimen/navigation_key_width"                android:layout_height="match_parent"                android:layout_weight="0"                systemui:keyCode="301"                systemui:glowBackground="@drawable/ic_sysbar_highlight"                android:visibility="gone"/> 

3.接着改动代码逻辑，文件路径：

frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java

在private void prepareNavigationBarView() {……}函数中加入显示音量加减的代码：

mNavigationBarView.getAddVolume().setVisibility(View.VISIBLE);    mNavigationBarView.getSubVolume().setVisibility(View.VISIBLE);

相应的函数getAddVolume()和getAddVolume()要在

frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java

中实现：

public View getAddVolume(){       return mCurrentView.findViewById(R.id.add);    }    public View getSubVolume(){        return mCurrentView.findViewById(R.id.sub);    } 

最后就是功能实现了。在

frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java

中加入监听函数：

private View.OnTouchListener mAddVolumeOnTouchListener = new View.OnTouchListener() {      public boolean onTouch(View v, MotionEvent ev) {      final int action = ev.getAction();                switch(action) {                case MotionEvent.ACTION_DOWN:                   is_down = true;                   Adjust_Volume(true);                   maddHandler.postDelayed(maddRun, ADJUST_VOLUME_DELAY * 2);                   break;                case MotionEvent.ACTION_MOVE:                   is_down = true;                   maddHandler.postDelayed(maddRun, ADJUST_VOLUME_DELAY * 2);    //             maddHandler.removeCallbacks(maddRun);                   break;                case MotionEvent.ACTION_UP:                   is_down = false;                   maddHandler.removeCallbacks(maddRun);                   break;                         }          return true;      }    };

  private View.OnTouchListener mSubVolumeOnTouchListener = new View.OnTouchListener() {           public boolean onTouch(View v, MotionEvent ev) {           final int action = ev.getAction();            int x, y;            //int mCode = ev.getAction();                switch (action) {                case MotionEvent.ACTION_DOWN:                  is_down = true;                  Adjust_Volume(false);                  msubHandler.postDelayed(msubRun, ADJUST_VOLUME_DELAY * 2);                  break;                case MotionEvent.ACTION_MOVE:                                    is_down = true;                  msubHandler.postDelayed(msubRun, ADJUST_VOLUME_DELAY * 2);                  //msubHandler.removeCallbacks(msubRun);                  break;                case MotionEvent.ACTION_UP:                  is_down = false;                  msubHandler.removeCallbacks(msubRun);                  break;            }            return true;        }    };

public void Adjust_Volume(boolean opition){            AudioManager audioManager = (AudioManager)mContext.getSystemService(Context.AUDIO_SERVICE);            if (audioManager != null) {                //                 // Adjust the volume in on key down since it is more                 // responsive to the user.                 //                    if(opition){                            audioManager.adjustSuggestedStreamVolume(                            AudioManager.ADJUST_RAISE,                           AudioManager.USE_DEFAULT_STREAM_TYPE,                           AudioManager.FLAG_SHOW_UI | AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);                    }else{                            audioManager.adjustSuggestedStreamVolume(                         AudioManager.ADJUST_LOWER,                        AudioManager.USE_DEFAULT_STREAM_TYPE,                        AudioManager.FLAG_SHOW_UI | AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);                    }            }    }