前言

今天客户提了个需求，因为我们的设备在正常情况下无法调节通话音量，只有在打电话过程中，按物理音量加减键才能出现调节通话音量seekBar，很不方便，于是乎需求就来了。需要优化两个地方

1、在正常情况下，按物理音量加减键都显示 通话音量调节seekBar,可方便快速调节通话音量

2、在Settings中提示音界面点击设置进入，增加通话音量调节seekBar

修改前1.png

修改前2.png

修改前

修改后1.png

修改后2.png

修改后

实现

第一个功能

先来完成第一个功能，还是通过Hierarchy View查看布局结构，查找到布局文件id为volume_dialog，通过在源码中搜索找到位于SystemUI中，volume_dialog.xml
源码位置 frameworks\base\packages\SystemUI\res\layout\volume_dialog.xml

对应的java类为 frameworks\base\packages\SystemUI\src\com\android\systemui\volume\VolumeDialog.java

修改代码

addRow(AudioManager.STREAM_VOICE_CALL,
            R.drawable.ic_volume_voice, R.drawable.ic_volume_voice, true);

原来的第四个参数为false，修改为true即可显示通话音量seekBar

为了便于说明，我们跟进addRow()中查看

private void addRow(int stream, int iconRes, int iconMuteRes, boolean important) {
    final VolumeRow row = initRow(stream, iconRes, iconMuteRes, important);
    if (!mRows.isEmpty()) {
        final View v = new View(mContext);
        v.setId(android.R.id.background);
        final int h = mContext.getResources()
                .getDimensionPixelSize(R.dimen.volume_slider_interspacing);
        final LinearLayout.LayoutParams lp =
                new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, h);
        mDialogContentView.addView(v, mDialogContentView.getChildCount() - 1, lp);
        row.space = v;
    }
    ...
}

传递的参数对应important，从字面意思理解重要对应显示，继续查看initRow都做了什么

private VolumeRow initRow(final int stream, int iconRes, int iconMuteRes, boolean important) {
    final VolumeRow row = new VolumeRow();
    row.stream = stream;
    row.iconRes = iconRes;
    row.iconMuteRes = iconMuteRes;
    row.important = important;
    row.view = mDialog.getLayoutInflater().inflate(R.layout.volume_dialog_row, null);
    row.view.setTag(row);
    row.header = (TextView) row.view.findViewById(R.id.volume_row_header);
    mSpTexts.add(row.header);
    row.slider = (SeekBar) row.view.findViewById(R.id.volume_row_slider);
    row.slider.setOnSeekBarChangeListener(new VolumeSeekBarChangeListener(row));

    // forward events above the slider into the slider
    row.view.setOnTouchListener(new OnTouchListener() {
        private final Rect mSliderHitRect = new Rect();
        private boolean mDragging;

        @SuppressLint("ClickableViewAccessibility")
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            row.slider.getHitRect(mSliderHitRect);
            if (!mDragging && event.getActionMasked() == MotionEvent.ACTION_DOWN
                    && event.getY() < mSliderHitRect.top) {
                mDragging = true;
            }
            if (mDragging) {
                event.offsetLocation(-mSliderHitRect.left, -mSliderHitRect.top);
                row.slider.dispatchTouchEvent(event);
                if (event.getActionMasked() == MotionEvent.ACTION_UP
                        || event.getActionMasked() == MotionEvent.ACTION_CANCEL) {
                    mDragging = false;
                }
                return true;
            }
            return false;
        }
    });
    row.icon = (ImageButton) row.view.findViewById(R.id.volume_row_icon);
    row.icon.setImageResource(iconRes);
    row.icon.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            Events.writeEvent(mContext, Events.EVENT_ICON_CLICK, row.stream, row.iconState);
            mController.setActiveStream(row.stream);
            if (row.stream == AudioManager.STREAM_RING) {
                final boolean hasVibrator = mController.hasVibrator();
                if (mState.ringerModeInternal == AudioManager.RINGER_MODE_NORMAL) {
                    if (hasVibrator) {
                        mController.setRingerMode(AudioManager.RINGER_MODE_VIBRATE, false);
                    } else {
                        final boolean wasZero = row.ss.level == 0;
                        mController.setStreamVolume(stream, wasZero ? row.lastAudibleLevel : 0);
                    }
                } else {
                    mController.setRingerMode(AudioManager.RINGER_MODE_NORMAL, false);
                    if (row.ss.level == 0) {
                        mController.setStreamVolume(stream, 1);
                    }
                }
            } else {
                final boolean vmute = row.ss.level == 0;
                mController.setStreamVolume(stream, vmute ? row.lastAudibleLevel : 0);
            }
            row.userAttempt = 0;  // reset the grace period, slider should update immediately
        }
    });
    row.settingsButton = (ImageButton) row.view.findViewById(R.id.volume_settings_button);
    row.settingsButton.setOnClickListener(mClickSettings);
    return row;
}

从上面可看出，将一些变量都保存到了VolumeRow中，设置了icon的点击事件，将当前对应的音量类型设置为最低(禁音), 设置seekBar的改变事件。通过过滤日志，查找到控制音量类型的显示和隐藏的代码块updateRowsH()

private boolean isVisibleH(VolumeRow row, boolean isActive) {
    return mExpanded && row.view.getVisibility() == View.VISIBLE
            || (mExpanded && (row.important || isActive))
            || !mExpanded && isActive;
}

private void updateRowsH() {
    if (D.BUG) Log.d(TAG, "updateRowsH");
    final VolumeRow activeRow = getActiveRow();
    updateFooterH();
    updateExpandButtonH();
    if (!mShowing) {
        trimObsoleteH();
    }
    // apply changes to all rows
    for (VolumeRow row : mRows) {
        final boolean isActive = row == activeRow;
        final boolean visible = isVisibleH(row, isActive);
        Log.e(TAG, "row==" + row.stream + " isActive=="+isActive + " visible="+visible);
        Util.setVisOrGone(row.view, visible);
        Util.setVisOrGone(row.space, visible && mExpanded);
        final int expandButtonRes = mExpanded ? R.drawable.ic_volume_settings : 0;
        if (expandButtonRes != row.cachedExpandButtonRes) {
            row.cachedExpandButtonRes = expandButtonRes;
            if (expandButtonRes == 0) {
                row.settingsButton.setImageDrawable(null);
            } else {
                row.settingsButton.setImageResource(expandButtonRes);
            }
        }
        Util.setVisOrInvis(row.settingsButton, false);
        updateVolumeRowHeaderVisibleH(row);
        row.header.setAlpha(mExpanded && isActive ? 1 : 0.5f);
        updateVolumeRowSliderTintH(row, isActive);
    }
}

遍历已经添加的音量类型集合mRows，依次判断是否处于活动状态，再和开始设置的important属性比较。mExpanded是否展开，默认只显示铃声音量控制，点击下拉的按钮，才完全显示其它的音量控制

mExpanded && row.view.getVisibility() == View.VISIBLE || (mExpanded && (row.important || isActive)) || !mExpanded && isActive

true && false || (true && (true || false)) || false && true --->true

好了，至此分析完毕，重新mmm push SystemUI.apk 查看效果

第二个功能

源码位置

Settings\res_ext\xml\edit_profile_prefs.xml
Settings\src\com\mediatek\audioprofile\Editprofile.java
Settings\src\com\mediatek\audioprofile\VolumeSeekBarPreference.java

在edit_profile_prefs.xml中仿照原来的Alarm volume和Ring volume，新增加一个Call volume

<!-- Media volume -->
<com.mediatek.audioprofile.VolumeSeekBarPreference
        android:key="media_volume"
        android:icon="@*android:drawable/ic_audio_vol"
        android:title="@string/media_volume_option_title" />

<!-- Alarm volume -->
<com.mediatek.audioprofile.VolumeSeekBarPreference
        android:key="alarm_volume"
        android:icon="@*android:drawable/ic_audio_alarm"
        android:title="@string/alarm_volume_option_title" />

<!-- Ring volume -->
<com.mediatek.audioprofile.VolumeSeekBarPreference
        android:key="ring_volume"
        android:icon="@*android:drawable/ic_audio_ring_notif"
        android:title="@string/ring_volume_option_title" />

<!-- Call volume -->
<com.mediatek.audioprofile.VolumeSeekBarPreference
        android:key="call_volume"
        android:icon="@drawable/ic_volume_voice"
        android:title="@string/call_volume_option_title" />

对应的drawable文件时从SystemUI中拷贝过来的，ic_volume_voice.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:height="24.0dp"
android:viewportHeight="48.0"
android:viewportWidth="48.0"
android:width="24.0dp" >

<path
    android:fillColor="#ff727272"
    android:pathData="M13.25,21.59c2.88,5.66 7.51,10.29 13.18,13.17l4.4,-4.41c0.55,-0.55 1.34,-0.71 2.03,-0.49C35.1,30.6 37.51,31.0 40.0,31.0c1.11,0.0 2.0,0.89 2.0,2.0l0.0,7.0c0.0,1.11 -0.89,2.0 -2.0,2.0C21.22,42.0 6.0,26.78 6.0,8.0c0.0,-1.1 0.9,-2.0 2.0,-2.0l7.0,0.0c1.11,0.0 2.0,0.89 2.0,2.0 0.0,2.4 0.4,4.9 1.14,7.1 0.2,0.6 0.06,1.48 -0.49,2.03l-4.4,4.42z" />

</vector>

接下来对应到 Editprofile.java 文件中，可以看到 KEY_ALARM_VOLUME 对应的preference初始化，依旧照葫芦画瓢，添加 KEY_CALL_VOLUME

private void initVolume(PreferenceScreen parent) {
    initVolumePreference(KEY_MEDIA_VOLUME, AudioManager.STREAM_MUSIC);
    initVolumePreference(KEY_ALARM_VOLUME, AudioManager.STREAM_ALARM);
    initVolumePreference(KEY_CALL_VOLUME, AudioManager.STREAM_VOICE_CALL);
    if (mVoiceCapable) {
        mVolume = initVolumePreference(KEY_RING_VOLUME, AudioManager.STREAM_RING);
        parent.removePreference(parent.findPreference(KEY_NOTIFICATION_VOLUME));
    } else {
        mVolume = initVolumePreference(KEY_NOTIFICATION_VOLUME,
                AudioManager.STREAM_NOTIFICATION);
        parent.removePreference(parent.findPreference(KEY_RING_VOLUME));
    }
}

重新编译，push替换后发现，UI倒是出来了，但是无法滑动，事情果然没那么简单，继续查看 initVolumePreference（）

private VolumeSeekBarPreference initVolumePreference(String key, int stream) {
    Log.d("@M_" + TAG, "Init volume preference, key = " + key + ",stream = " + stream);
    final VolumeSeekBarPreference volumePref = (VolumeSeekBarPreference) findPreference(key);
    volumePref.setStream(stream);
    volumePref.setCallback(mVolumeCallback);
    volumePref.setProfile(mKey);

    return volumePref;
}

保存了当前的音量调节类型，设置seekBar回调事件，接下来看看回调处理了什么

private final class VolumePreferenceCallback implements VolumeSeekBarPreference.Callback {
    private SeekBarVolumizer mCurrent;

    @Override
    public void onSampleStarting(SeekBarVolumizer sbv) {
        if (mCurrent != null && mCurrent != sbv) {
            mCurrent.stopSample();
        }
        mCurrent = sbv;
        if (mCurrent != null) {
            mHandler.removeMessages(H.STOP_SAMPLE);
            mHandler.sendEmptyMessageDelayed(H.STOP_SAMPLE, SAMPLE_CUTOFF);
        }
    }

    public void onStreamValueChanged(int stream, int progress) {
        if (stream == AudioManager.STREAM_RING) {
            mHandler.removeMessages(H.UPDATE_RINGER_ICON);
            mHandler.obtainMessage(H.UPDATE_RINGER_ICON, progress, 0).sendToTarget();
        }
    }

    public void stopSample() {
        if (mCurrent != null) {
            mCurrent.stopSample();
        }
    }

    public void ringtoneChanged() {
        if (mCurrent != null) {
            mCurrent.ringtoneChanged();
        } else {
            mVolume.getSeekBar().ringtoneChanged();
        }
    }
};

当我们点击或者是滑动seekBar时，会根据当前设置的音量大小播放一段短暂的默认铃音，当铃音未播放完成时，再次点击将不进行播放。继续跟进 VolumeSeekBarPreference.java 中

@Override
protected void onBindView(View view) {
    super.onBindView(view);
    if (mStream == 0) {
        Log.w(TAG, "No stream found, not binding volumizer  ");
        return;
    }
    getPreferenceManager().registerOnActivityStopListener(this);
    final SeekBar seekBar = (SeekBar) view.findViewById(com.android.internal.R.id.seekbar);
    if (seekBar == mSeekBar) {
        return;
    }
    mSeekBar = seekBar;
    final SeekBarVolumizer.Callback sbvc = new SeekBarVolumizer.Callback() {
        @Override
        public void onSampleStarting(SeekBarVolumizer sbv) {
            if (mCallback != null) {
                mCallback.onSampleStarting(sbv);
            }
        }
    };
    final Uri sampleUri = mStream == AudioManager.STREAM_MUSIC ? getMediaVolumeUri() : null;
    if (mVolumizer == null) {
        mVolumizer = new SeekBarVolumizer(getContext(), mStream, sampleUri, sbvc, mKey);
    }
    //mVolumizer.setProfile(mKey);
    mVolumizer.setSeekBar(mSeekBar);
}

mStream == 0, 直接return，会不会和这有关系呢，来看下各个音量调节类型对应的int值

/** Used to identify the volume of audio streams for phone calls */
public static final int STREAM_VOICE_CALL = 0;
/** Used to identify the volume of audio streams for the phone ring and message alerts */
public static final int STREAM_RING = 2;
/** Used to identify the volume of audio streams for music playback */
public static final int STREAM_MUSIC = 3;
/** Used to identify the volume of audio streams for alarms */
public static final int STREAM_ALARM = 4;

我们新增的 STREAM_VOICE_CALL对应的mStream正好为0，直接给return掉了，所以修改为 mStream < 0 即可，重新编译 push 发现成功了。

具体的音量调节逻辑在 packages\apps\Settings\src\com\mediatek\audioprofile\SeekBarVolumizer.java 中，感兴趣的可继续深究，肯定离不开调用 .setStreamVolume()方法，大概看了一眼，主要是onProgressChanged()回调，通过postSetVolume(progress)方法，发送MSG_SET_STREAM_VOLUME消息，最终调用saveVolume()