信号的VIEW

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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/system_icons"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:gravity="center_vertical">

    <com.android.keyguard.AlphaOptimizedLinearLayout android:id="@+id/statusIcons"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:gravity="center_vertical"
        android:orientation="horizontal"/>
<---------信号的VIEW-------------------------------------->
    <include layout="@layout/signal_cluster_view"
        android:id="@+id/signal_cluster"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="2.5dp"/>

    <!-- battery must be padded below to match assets -->
    <com.android.systemui.BatteryMeterView android:id="@+id/battery"
        android:layout_height="14.5dp"
        android:layout_width="9.5dp"
        android:visibility="gone"
        android:layout_marginBottom="@dimen/battery_margin_bottom"/>
</LinearLayout>