Android 如何在选项卡的中心显示图像？

我在android中创建了一个选项卡，它只显示图像，不包含任何文本，我希望图像显示在选项卡的中心。有多个选项卡，每个选项卡都包含图像，但问题是图像不显示在每个选项卡的中心

这是我的xml

---

1-创建一个名为report_tabs.xml或任意名称的布局文件

在“报告”选项卡中使用此代码

     <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/layout_tabsLayout"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:background="@drawable/btn_selector"
     android:gravity="center"
     android:orientation="vertical"
     >

     <ImageView
     android:id="@+id/img_icon"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="center"
     android:layout_marginTop="3dp"
     />
    </LinearLayout>

3-在drawable中创建一个名为tab_icon_selector的文件，用于更改tab上的图标单击如下：-

    <?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Non focused states -->
    <item android:state_focused="false" android:state_selected="false" 
          android:state_pressed="false" android:drawable="@drawable/medical_icon_unselect"    
     />
     <item android:state_focused="false" android:state_selected="true" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" /> 
     <!-- Focused states -->
     <item android:state_focused="true" android:state_selected="false" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" />
     <item android:state_focused="true" android:state_selected="true" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" /> 
     <!-- Pressed -->
     <item android:state_pressed="true" android:drawable="@android:color/transparent"/> 
     </selector>

---

现在，您可以创建自定义选项卡栏，图像图标将位于选项卡的中心。

1-创建一个名为report_tabs.xml或任意名称的布局文件

在“报告”选项卡中使用此代码

     <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/layout_tabsLayout"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:background="@drawable/btn_selector"
     android:gravity="center"
     android:orientation="vertical"
     >

     <ImageView
     android:id="@+id/img_icon"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="center"
     android:layout_marginTop="3dp"
     />
    </LinearLayout>

3-在drawable中创建一个名为tab_icon_selector的文件，用于更改tab上的图标单击如下：-

    <?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Non focused states -->
    <item android:state_focused="false" android:state_selected="false" 
          android:state_pressed="false" android:drawable="@drawable/medical_icon_unselect"    
     />
     <item android:state_focused="false" android:state_selected="true" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" /> 
     <!-- Focused states -->
     <item android:state_focused="true" android:state_selected="false" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" />
     <item android:state_focused="true" android:state_selected="true" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" /> 
     <!-- Pressed -->
     <item android:state_pressed="true" android:drawable="@android:color/transparent"/> 
     </selector>

现在，您可以创建自定义选项卡栏，您的图像图标将位于选项卡的中心

    <?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Non focused states -->
    <item android:state_focused="false" android:state_selected="false" 
          android:state_pressed="false" android:drawable="@drawable/medical_icon_unselect"    
     />
     <item android:state_focused="false" android:state_selected="true" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" /> 
     <!-- Focused states -->
     <item android:state_focused="true" android:state_selected="false" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" />
     <item android:state_focused="true" android:state_selected="true" 
     android:state_pressed="false" android:drawable="@drawable/medical_icon_sel" /> 
     <!-- Pressed -->
     <item android:state_pressed="true" android:drawable="@android:color/transparent"/> 
     </selector>