Android 按下时设置ListView选择器颜色时出现问题

我有以下列表视图，并遵循此SO问题的答案，但没有运气：

这是我的ar_选择器.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:state_enabled="false" android:state_focused="true"
        android:drawable="@android:color/transparent" />
  <item android:state_pressed="true"
        android:drawable="@color/solid_red" />
  <item android:state_focused="true"
        android:drawable="@android:color/transparent" />
</selector>

---

当我按下ListViewItem时，不会显示任何内容。

Sheehan Alam，请使用以下代码：-

list_selector.xml

  <?xml version="1.0" encoding="utf-8"?>
  <selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item
   android:state_selected="false"
    android:state_pressed="false"
    android:drawable="@drawable/gradient_bg" />

  <item android:state_pressed="true"
    android:drawable="@drawable/gradient_bg_hover" />

  <item android:state_selected="true"
 android:state_pressed="false"
    android:drawable="@drawable/gradient_bg_hover" />
 </selector>

gradient_bg.xml

 <shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="rectangle">
  <gradient
  android:startColor="#f1f1f2"
  android:centerColor="#e7e7e8"
  android:endColor="#cfcfcf"
  android:angle="270" />
  </shape>

gradient_bg_hover.xml

  <?xml version="1.0" encoding="utf-8"?>
  <shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="rectangle">
   <gradient
  android:startColor="#18d7e5"
    android:centerColor="#16cedb"
  android:endColor="#09adb9"
  android:angle="270" />
  </shape>

  <?xml version="1.0" encoding="utf-8"?>
  <shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="rectangle">
   <gradient
  android:startColor="#18d7e5"
    android:centerColor="#16cedb"
  android:endColor="#09adb9"
  android:angle="270" />
  </shape>