Realize the function of progress bar through layerdrawable

The renderings are as follows ：

First, the background picture is as follows , The bottom layer is the background , The upper layer is the color of the progress bar

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <corners android:radius="6dp" />
            <solid android:color="#23252c" />
        </shape>
    </item>

    <item android:width="0dp" android:id="@+id/progress_bg">
        <shape android:shape="rectangle">
            <gradient android:startColor="#006580df"
                android:endColor="#ff6580df"
                android:angle="0"/>
            <corners android:topLeftRadius="6dp"
                android:bottomLeftRadius="6dp"/>
        </shape>
    </item>

</layer-list>

Then pass the progress value , Dynamically modify the width of the upper picture of the above picture , The processing logic is as follows ：

LayerDrawable rootBg = (LayerDrawable) mRootView.getBackground();
Drawable progressBg = rootBg.findDrawableByLayerId(R.id.progress_bg);
progressBg.setBounds(0, 0,(int) (mRootView.getWidth() * progress / 100L), getHeight());

The key code is findDrawableByLayerId, Through this method, the function can get LayerDrawable A picture of a layer required in . Update the drawable Of bound That is to say .