android SystemUI阿拉伯语言下系统图标和通知图标交换位置
大家都知道，阿拉伯语言的顺序和我们正常读取语言的顺序不一样，阿拉伯的读取方式是从右到左，即RTL,而我们平常的是LTR,导致有android系统有些应用在阿拉伯语言切换下需要重写调整界面，其实android4.2开始，有对layoutRtl进行支持，来适配RTL下app的兼容阿拉伯语/波斯语等阅读习惯，可以在manifest的application标签添加：android:supportsRtl 取值：true/false，与此同时，layout中引入了如下属性兼容右左模式：
- paddingStart & paddingEnd 是根据左右对齐方式来起作用的
- 左对齐时, paddingStart 对应 paddingLeft, paddingEnd 对应 paddingRight
- 右对齐时, 正好相反
- 使用MarginStart和MarginEnd来替代MarginLeft和MarginRight
以上是新增加的RTL的属性，下面讲讲上次遇到的bug，将SystemUI状态栏中系统图标和通知图标交换位置的代码
交换前代码：
<?xml version="1.0" encoding="utf-8"?>
<!--
/* apps/common/assets/default/default/skins/StatusBar.xml
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
-->
<!-- M: Support "SystemUI - Dual SIM". -->
<!-- android:background="@drawable/status_bar_closed_default_background" -->
<com.android.systemui.statusbar.phone.PhoneStatusBarView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"
android:id="@+id/status_bar"
android:background="@drawable/system_bar_background"
android:orientation="vertical"
android:focusable="true"
android:descendantFocusability="afterDescendants"
android:fitsSystemWindows="true"
>
<ImageView
android:id="@+id/notification_lights_out"
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="match_parent"
android:paddingStart="6dip"
android:paddingBottom="2dip"
android:src="@drawable/ic_sysbar_lights_out_dot_small"
android:scaleType="center"
android:visibility="gone"
/>
<LinearLayout android:id="@+id/status_bar_contents"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingStart="6dip"
android:paddingEnd="6dip"
android:orientation="horizontal"
>
<LinearLayout android:id="@+id/system_icon_area"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal">
<LinearLayout android:id="@+id/statusIcons"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:orientation="horizontal"/>
<LinearLayout
android:id="@+id/signal_battery_cluster"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:paddingStart="2dp"
android:orientation="horizontal"
android:gravity="center"
>
<include layout="@layout/gemini_signal_cluster_view"
android:id="@+id/signal_cluster"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<!-- M: Support Laptop Battery Status . @{ -->
<com.mediatek.systemui.statusbar.util.LaptopBatteryView
android:id="@+id/laptop_battery"
android:layout_height="18dp"
android:layout_width="20dp"
android:layout_marginBottom="0.33dp"
android:layout_marginStart="4dip"
android:visibility="gone"
/>
<!-- M: Support Laptop Battery Status . }@ -->
<!-- M: Support "SystemUI - Battery Percentage". @{ -->
<TextView
android:id="@+id/percentage"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:visibility = "gone"
android:paddingStart="4dip"
android:textAppearance="@style/TextAppearance.StatusBar.Clock"
/>
<!-- M: Support "SystemUI - Battery Percentage". }@ -->
<!-- battery must be padded below to match assets -->
<com.android.systemui.BatteryMeterView
android:id="@+id/battery"
android:layout_height="16dp"
android:layout_width="10.5dp"
android:layout_marginBottom="0.33dp"
android:layout_marginStart="4dip"
/>
</LinearLayout>
<com.android.systemui.statusbar.policy.Clock
android:id="@+id/clock"
android:textAppearance="@style/TextAppearance.StatusBar.Clock"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:singleLine="true"
android:paddingStart="6dip"
android:gravity="center_vertical|start"
/>
</LinearLayout>
<LinearLayout
android:id="@+id/notification_icon_area"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal"
>
<com.android.systemui.statusbar.StatusBarIconView android:id="@+id/moreIcon"
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="match_parent"
android:src="@drawable/stat_notify_more"
android:visibility="gone"
/>
<com.android.systemui.statusbar.phone.IconMerger android:id="@+id/notificationIcons"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:gravity="center_vertical|end"
android:orientation="horizontal"/>
</LinearLayout>
</LinearLayout>
<LinearLayout android:id="@+id/ticker"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingStart="6dip"
android:animationCache="false"
android:orientation="horizontal" >
<ImageSwitcher android:id="@+id/tickerIcon"
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="@dimen/status_bar_icon_size"
android:layout_marginEnd="4dip"
>
<com.android.systemui.statusbar.AnimatedImageView
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="@dimen/status_bar_icon_size"
android:scaleType="center"
/>
<com.android.systemui.statusbar.AnimatedImageView
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="@dimen/status_bar_icon_size"
android:scaleType="center"
/>
</ImageSwitcher>
<com.android.systemui.statusbar.phone.TickerView android:id="@+id/tickerText"
android:layout_width="0dip"
android:layout_weight="1"
android:layout_height="wrap_content"
android:paddingTop="2dip"
android:paddingEnd="10dip">
<TextView
android:textAppearance="@style/TextAppearance.StatusBar.PhoneTicker"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
/>
<TextView
android:textAppearance="@style/TextAppearance.StatusBar.PhoneTicker"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
/>
</com.android.systemui.statusbar.phone.TickerView>
</LinearLayout>
</com.android.systemui.statusbar.phone.PhoneStatusBarView>
交换后代码：
<?xml version="1.0" encoding="utf-8"?>
<!--
/* apps/common/assets/default/default/skins/StatusBar.xml
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
-->
<!-- M: Support "SystemUI - Dual SIM". -->
<!-- android:background="@drawable/status_bar_closed_default_background" -->
<com.android.systemui.statusbar.phone.PhoneStatusBarView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui"
android:id="@+id/status_bar"
android:background="@drawable/system_bar_background"
android:orientation="vertical"
android:focusable="true"
android:descendantFocusability="afterDescendants"
android:fitsSystemWindows="true"
>
<ImageView
android:id="@+id/notification_lights_out"
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="match_parent"
android:paddingStart="6dip"
android:paddingBottom="2dip"
android:src="@drawable/ic_sysbar_lights_out_dot_small"
android:scaleType="center"
android:visibility="gone"
/>
<LinearLayout android:id="@+id/status_bar_contents"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingStart="6dip"
android:paddingEnd="6dip"
android:orientation="horizontal"
>
<LinearLayout
android:id="@+id/notification_icon_area"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal"
>
<com.android.systemui.statusbar.StatusBarIconView android:id="@+id/moreIcon"
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="match_parent"
android:src="@drawable/stat_notify_more"
android:visibility="gone"
/>
<com.android.systemui.statusbar.phone.IconMerger android:id="@+id/notificationIcons"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:gravity="center_vertical"
android:orientation="horizontal"/>
</LinearLayout>
<LinearLayout android:id="@+id/system_icon_area"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal">
<LinearLayout android:id="@+id/statusIcons"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:orientation="horizontal"/>
<LinearLayout
android:id="@+id/signal_battery_cluster"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:paddingStart="2dp"
android:orientation="horizontal"
android:gravity="center"
>
<include layout="@layout/gemini_signal_cluster_view"
android:id="@+id/signal_cluster"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<!-- M: Support Laptop Battery Status . @{ -->
<com.mediatek.systemui.statusbar.util.LaptopBatteryView
android:id="@+id/laptop_battery"
android:layout_height="18dp"
android:layout_width="20dp"
android:layout_marginBottom="0.33dp"
android:layout_marginStart="4dip"
android:visibility="gone"
/>
<!-- M: Support Laptop Battery Status . }@ -->
<!-- M: Support "SystemUI - Battery Percentage". @{ -->
<TextView
android:id="@+id/percentage"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:visibility = "gone"
android:paddingStart="4dip"
android:textAppearance="@style/TextAppearance.StatusBar.Clock"
/>
<!-- M: Support "SystemUI - Battery Percentage". }@ -->
<!-- battery must be padded below to match assets -->
<com.android.systemui.BatteryMeterView
android:id="@+id/battery"
android:layout_height="16dp"
android:layout_width="10.5dp"
android:layout_marginBottom="0.33dp"
android:layout_marginStart="4dip"
/>
</LinearLayout>
<com.android.systemui.statusbar.policy.Clock
android:id="@+id/clock"
android:textAppearance="@style/TextAppearance.StatusBar.Clock"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:singleLine="true"
android:paddingStart="6dip"
android:gravity="left|center"
/>
</LinearLayout>
</LinearLayout>
<LinearLayout android:id="@+id/ticker"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingStart="6dip"
android:animationCache="false"
android:orientation="horizontal" >
<ImageSwitcher android:id="@+id/tickerIcon"
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="@dimen/status_bar_icon_size"
android:layout_marginEnd="4dip"
>
<com.android.systemui.statusbar.AnimatedImageView
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="@dimen/status_bar_icon_size"
android:scaleType="center"
/>
<com.android.systemui.statusbar.AnimatedImageView
android:layout_width="@dimen/status_bar_icon_size"
android:layout_height="@dimen/status_bar_icon_size"
android:scaleType="center"
/>
</ImageSwitcher>
<com.android.systemui.statusbar.phone.TickerView android:id="@+id/tickerText"
android:layout_width="0dip"
android:layout_weight="1"
android:layout_height="wrap_content"
android:paddingTop="2dip"
android:paddingEnd="10dip">
<TextView
android:textAppearance="@style/TextAppearance.StatusBar.PhoneTicker"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
/>
<TextView
android:textAppearance="@style/TextAppearance.StatusBar.PhoneTicker"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
/>
</com.android.systemui.statusbar.phone.TickerView>
</LinearLayout>
</com.android.systemui.statusbar.phone.PhoneStatusBarView>
此外，记得在AndroidManifest.xml的application中添加android:supportsRtl="true"，从而支持RTL模式