了解android复杂形状绘图

Question

I want to have a shape consisting of a circle and a line. I probably just don't understand how things work here.

First, I thought about creating a vertical line by rotating a line shape.

<rotate xmlns:android="http://schemas.android.com/apk/res/android"
    android:fromDegrees="0"
    android:toDegrees="90"
    >
    <shape android:shape="line">
        <stroke
            android:width="2dp"
            android:dashWidth="2dp"
            android:dashGap="4dp"
            android:color="@android:color/holo_blue_bright"
            />
    </shape>
</rotate>

This does not create a vertical line as expected, it creates a horizontal line to me: . Whenever I change the fromDegrees attribute to 90, I have a vertical one. toDegrees is just ignored.

<rotate xmlns:android="http://schemas.android.com/apk/res/android"
    android:fromDegrees="90"
    android:toDegrees="190"
    >
    <shape android:shape="line">
        <stroke
            android:width="2dp"
            android:dashWidth="2dp"
            android:dashGap="4dp"
            android:color="@android:color/holo_blue_bright"
            />
    </shape>
</rotate>

The result is now .

Ok, so, I don't understand, but whatever. Let's add a circle so that I get something like this:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <rotate android:fromDegrees="90">
            <shape android:shape="line">
                <stroke
                    android:width="2dp"
                    android:dashWidth="2dp"
                    android:dashGap="4dp"
                    android:color="@android:color/holo_blue_bright" />
            </shape>
        </rotate>
    </item>
    <item>
        <shape android:shape="oval">
            <stroke android:color="#000" android:width="2dp" />
            <solid android:color="@android:color/white" />
        </shape>
    </item>
</layer-list>

What I get is just a circle: Having thought that the circle fills the entire size of the shape, being drawn over the entire line, I added a scale element to have the circle scaled 50% down.

<scale
    android:scaleWidth="50%"
    android:scaleHeight="50%">
    <shape android:shape="oval">
        <stroke android:color="#000" android:width="2dp" />
    </shape>
</scale>

After that, the circle just disappeared and I got only the line again. So, can anyone help me understand, what's going on here?

Answer 1

在这里看看答案： https : //stackoverflow.com/a/15239304/1064689旋转度是指动画。