Android：ProgressBar的不確定模式

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ProgressBar
        android:id="@+id/progress_bar_indeterminate"
        style="@android:style/Widget.ProgressBar.Horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:indeterminate="true"
        android:indeterminateDrawable="@drawable/progress_indeterminate_horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

打開不確定模式，

anroid:indeterminate="true"

設置不確定模式動畫。

android:indeterminateDrawable="@drawable/progress_indeterminate_horizontal"
 

動畫drawable文件：

<?xml version="1.0" encoding="utf-8"?>
<animation-list
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:oneshot="false">
    <item android:drawable="@drawable/progressbar_indeterminate1" android:duration="300" />
    <item android:drawable="@drawable/progressbar_indeterminate2" android:duration="300" />
    <item android:drawable="@drawable/progressbar_indeterminate3" android:duration="300" />
</animation-list>

三張狀態圖片：

progressbar_indeterminate1

     

progressbar_indeterminate2

    

progressbar_indeterminate3