What's the meaning of android:progressBarStyle

问题:

I've been looking through the documentation for ProgressBar class and found these attributes:

• android:progressBarStyle
• android:progressBarStyleHorizontal
• android:progressBarStyleLarge
• android:progressBarStyleSmall

These four parameters are supposed to be a reference to some style as I take it. So the question is, what are these for? Style for the progress bar is set via android:style attribute and a reference to the global style attributes.

Documentation doesn't say anything helpful, searched the Web, found nothing.

回答1:

The four attributes that you mention can be applied to a ProgressBar's style like so:

style="?android:attr/progressBarStyleHorizontal"

The style constant android:progressBarStyleHorizontal is your typical incremental progress bar:

While the other three are varying sizes of the same circular progress bar:

style="?android:attr/progressBarStyleSmall"

style="?android:attr/progressBarStyle"

style="?android:attr/progressBarStyleLarge"

Update:

According to adamp's comments:

These are attributes of the theme that point at themed styles you can use for progress indicators...They are not attributes for ProgressBar itself.

回答2:

In case if someone is looking for full block of code

<ProgressBar
android:id="@+id/ProgressBar2"
style="?android:attr/progressBarStyleLarge"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

回答3:

The confusing part is that normally, you can define a default style for a widget (e.g. a button) like this:

<item name="android:buttonStyle">@style/Widget.AppCompat.Button.Colored</item>

All buttons will then by default have this style applied.

One would think that the progressBarStyle attribute would do the same for ProgressBar if doing this:

<item name="android:progressBarStyle">@style/Widget.AppCompat.ProgressBar</item>

But that is not the case, since progressBarStyle belongs to the ActionBar styleable.