Remove padding in horizontal progress bar

Question

In our application we need an indeterminate progress bar, like so:

We can achieve this by setting a negative margin on the ProgressBar, like this:

<ProgressBar
    android:id="@+id/progressbar"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:indeterminate="true"
    android:marginTop="-7dp"
    android:visibility="@{loading ? View.VISIBLE : View.GONE}" />

BUT because ConstraintLayout does not support negative margins, it will look like this:

OK, the negative margin was a hack. Let's replace it with a different hack, shall we? Let's introduce our custom view CustomProgressBar, which extends ProgressBar and overrides its onDraw method, like this:

@Override
protected void onDraw(Canvas canvas) {
    int marginTop = dpToPx(7);
    canvas.translate(0, -marginTop);
    super.onDraw(canvas);
}

But all of this smells like bad code. There has to be a better solution! What would you recommend?

Answer 1

Solution that feels less like a hack: Wrap a huge ProgressBar in a smaller FrameLayout. That way the FrameLayout constrains its height, but the ProgressBar still shows in full.

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="4dp">

    <ProgressBar
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="32dp"
        android:layout_gravity="center" />

</FrameLayout>

Answer 2

Another way to do this is to use a Guideline and center ProgressBar between the parent top and the guideline.

<ProgressBar
    android:id="@+id/progressBar2"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="0dp"
    android:paddingTop="-4dp"
    android:layout_height="wrap_content"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintBottom_toTopOf="@+id/guideline"
    app:layout_constraintTop_toTopOf="parent" />

<android.support.constraint.Guideline
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/guideline"
    android:orientation="horizontal"
    app:layout_constraintGuide_begin="4dp" />

Answer 3

I encountered the same problem as well. And like you said, I come across numerous solutions which all seem like a hack that might break something else down the line. With that said, I came across one solution which is to use this library instead for progress bar.

One thing to note is, it tells you to integrate it by adding:

compile 'me.zhanghai.android.materialprogressbar:library:1.3.0'

However, when I used this, it gave me an error from an Android support library for Floating Action Bar. So I'll recommend you to use this instead:

compile 'me.zhanghai.android.materialprogressbar:library:1.1.7'

A sample code snippet on how I used it:

<me.zhanghai.android.materialprogressbar.MaterialProgressBar
    android:id="@+id/reviewProgressBar"
    style="@style/Widget.MaterialProgressBar.ProgressBar.Horizontal"
    android:layout_width="match_parent"
    android:layout_height="6dp"
    android:layout_below="@+id/my_toolbar"
    android:indeterminate="false"
    app:mpb_progressStyle="horizontal"
    app:mpb_useIntrinsicPadding="false"/>

Hope this helps!