Android开发之渐变色

Android开发之渐变色

在android.graphics中提供了有关Gradient类，包含LinearGradient线性渐变、 RadialGradient径向渐变和SweepGradient梯度渐变三种，它们的基类为android.graphics.Shader。

1. LinearGradient 线性渐变

• 构造体

LinearGradient(float x0, float y0, float x1, float y1, int[] colors, float[] positions, Shader.TileMode tile)


LinearGradient(float x0, float y0, float x1, float y1, int color0, int color1, Shader.TileMode tile)


• 例子如下

Paint paint =new Paint();
//两个坐标形成变量，规定了渐变的方向和间距大小，着色器为镜像
LinearGradient linearGradient =new LinearGradient(0,0,200,0, Color.RED,Color.BLUE, Shader.TileMode.MIRROR);
paint.setShader(linearGradient);
paint.setStrokeWidth(50);
canvas.drawLine(0,getMeasuredHeight()/2,getMeasuredWidth(),getMeasuredHeight()/2, paint);


LinearGradient

2. RadialGradient 径向/放射渐变

• 构造体

RadialGradient(float x, float y, float radius, int[] colors, float[] positions, Shader.TileMode tile)


RadialGradient(float x, float y, float radius, int color0, int color1, Shader.TileMode tile)


• 例子如下

paint =new Paint();
radialGradient =new RadialGradient(240,360,200, new int[]{Color.BLUE, Color.GREEN, Color.RED },null, Shader.TileMode.CLAMP);
paint.setShader(radialGradient);
canvas.drawCircle(240,360,200,paint);


RadialGradient

3. SweepGradient 扫描/梯度/扇形渐变

构造体

SweepGradient(float x, float y, int[] colors, float[] positions)


SweepGradient(float x, float y, int color0, int color1)


• 例子

paint =new Paint();
int[] colors = new int[]{Color.GREEN, Color.GREEN, Color.BLUE, Color.RED, Color.RED};
sweepGradient = new SweepGradient(240, 360,colors,null);
paint.setShader(sweepGradient);
canvas.drawCircle(x,y,200,paint);


SweepGradient

＼( ^o ^)／了解!