为什么LinearGradient构造函数的此参数似乎不起作用? [英] Why doesn't this argument of the LinearGradient constructor seem to work?
问题描述
我想将具有线性渐变的自定义可绘制对象设置为我的SeekBar中条的背景可绘制对象.我在以下代码段的第二条语句中创建LinearGradient，并这样做:
I want to set a custom drawable with a linear gradient as the background drawable of the bar in my SeekBar. I am creating the LinearGradient in the second statement in the following snippet, and doing it like so:
// Creating the drawable:
ShapeDrawable shapeDrawable = new ShapeDrawable(new RectShape());
Shader linearGradientShader = new LinearGradient(0, 0, 300, 20, new int[] { Color.RED, Color.BLUE },
new float[] { 0, 1 }, Shader.TileMode.CLAMP);
shapeDrawable.getPaint().setShader(linearGradientShader);
shapeDrawable.setBounds(10, 10, 300, 30);
seekBar.setProgressDrawable(shapeDrawable);
这里的问题是，根据 规范 ，第6个参数定义为
The problem here is that, according to the specification, the 6th parameter is defined as
可能为空.颜色数组中每种相应颜色的相对位置[0..1].如果为null，则颜色会沿着渐变线均匀分布.
May be null. The relative positions [0..1] of each corresponding color in the colors array. If this is null, the the colors are distributed evenly along the gradient line.
我希望红色和蓝色都均匀分布，即一半的形状应偏红色，一半的颜色应偏蓝色(如下图所示).
I wanted both the red and blue colors to be distributed evenly, i.e. half the shape should appear redish and half should appear bluish (like the following image).
所以我尝试了null，new float[] {0, 0.5f}和new float[] {0, 1}作为第6个参数的值.我分别得到以下三个结果.
So I tried null, new float[] {0, 0.5f}, and new float[] {0, 1} as values of the 6th argument. I got the following three results respectively.
-
对于
null:
对于new float[] {0, 0.5f}:
对于new float[] {0, 1}:
显示我要去哪里错了?我该如何解决?
推荐答案
使用
ShapeDrawable#setShaderFactory(ShapeDrawable.ShaderFactory工厂)
ShapeDrawable#setShaderFactory(ShapeDrawable.ShaderFactory factory)
工厂有一个方法Shader resize(int width, int height)，每次您的可绘制范围更改时都会调用该方法，在这里您应该根据width/height参数返回您的LinearGradient着色器
the factory has a method Shader resize(int width, int height) which is called every time your drawable bounds change and this is a place where you should return your LinearGradient shader based on width / height parameters
您将看到，现在只需传递null positions，颜色就会均匀分布
as you will see you can now just pass null positions and colors will be distributed evenly
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