Android 中的圆形渐变

Android 中的圆形渐变

java
public class GradientView extends View {
    private Paint mPaint;
    private RadialGradient mRadialGradient;
    
    public GradientView(Context context) {
        super(context);
        init();
    }
    
    public GradientView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }
    
    public GradientView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }
    
    private void init() {
        mPaint = new Paint();
        mRadialGradient = new RadialGradient(
            getWidth() / 2, getHeight() / 2, getWidth() / 2,
            Color.parseColor("#FF0000"), Color.parseColor("#00FF00"),
            Shader.TileMode.CLAMP
        );
        mPaint.setShader(mRadialGradient);
    }
    
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(getWidth() / 2, getHeight() / 2, getWidth() / 2, mPaint);
    }
}

xml
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
            android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_centerInParent="true" />