android drawble 阴影 android view阴影

7.2 setShadowLayer与阴影效果

public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mPaint = new Paint();

        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setStyle(Paint.Style.STROKE);

        mPaint.setTextSize(ConvertUtils.sp2px(22));

        //radius : 模糊半径,参数越大,越模糊,越小,越清晰,为0则阴影消失
        //dx : 阴影的横向偏移距离 ,正值向右偏移,负值向左偏移
        //dy : 阴影的纵向偏移距离 ,正值向下偏移,负值向上偏移
        //shadowColor :绘制阴影的画笔颜色,对图片阴影无效
        mPaint.setShadowLayer(1, 10, 10, Color.RED);
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog);
    }


    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        canvas.drawColor(Color.WHITE);

        canvas.drawText("文字阴影", 100, 100, mPaint);

        canvas.drawCircle(300, 200, 50, mPaint);

        Rect rect = new Rect(300, 300, bitmap.getWidth(), bitmap.getHeight());
        canvas.drawBitmap(bitmap, null, rect, mPaint);
    }


}

---

清除阴影

@SuppressLint("AppCompatCustomView")
public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;

    // 是否绘制阴影
    private boolean isShowShadow;

    public void setShowShadow(boolean showShadow) {
        isShowShadow = showShadow;
        postInvalidate();
    }

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mPaint = new Paint();

        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setStyle(Paint.Style.STROKE);

        mPaint.setTextSize(ConvertUtils.sp2px(22));

        //radius : 模糊半径,参数越大,越模糊,越小,越清晰,为0则阴影消失
        //dx : 阴影的横向偏移距离 ,正值向右偏移,负值向左偏移
        //dy : 阴影的纵向偏移距离 ,正值向下偏移,负值向上偏移
        //shadowColor :绘制阴影的画笔颜色,对图片阴影无效
//        mPaint.setShadowLayer(1, 10, 10, Color.RED);
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog);
    }


    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (isShowShadow) {
            mPaint.setShadowLayer(1, 10, 10, Color.RED);
        } else {
            mPaint.clearShadowLayer();
        }
        canvas.drawColor(Color.WHITE);

        canvas.drawText("文字阴影", 100, 100, mPaint);

        canvas.drawCircle(300, 200, 50, mPaint);

        Rect rect = new Rect(300, 300, bitmap.getWidth(), bitmap.getHeight());
        canvas.drawBitmap(bitmap, null, rect, mPaint);
    }


}

public class MainActivity extends BaseActivity<ActivityMainBinding> {


    private boolean isShow = false;

    @Override
    protected int getLayoutId() {
        return R.layout.activity_main;
    }

    @Override
    protected void getBundleExtras(Bundle extras) {

    }

    @Override
    protected void initView() {

        mViewBinding.tv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mViewBinding.myview.setShowShadow(isShow);
                isShow = !isShow;
            }
        });

    }

    @Override
    protected void initData() {

    }

    @Override
    protected void initListener() {

    }


}

---

7.2.3给文字添加阴影

可以直接在XML 里设置

<TextView
            android:id="@+id/tv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="过江千尺浪"
            android:textSize="30sp"
            android:shadowColor="@color/black"
            android:shadowDx="10"
            android:shadowDy="10"
            android:shadowRadius="10"/>

代码

mViewBinding.tv.setShadowLayer(10, 10, 10, Color.BLACK);

这个是textview 的set 方法里有这个参数

---

7.3BlurMaskFilter 发光效果与图片阴影

定义:发光效果只能算是高斯模糊效果,只会影响边缘效果,不会影响内部

        发光颜色不能指定,边缘啥颜色就是就是啥颜色

@SuppressLint("AppCompatCustomView")
public class MyTextView extends TextView {

    private Paint mPaint;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mPaint = new Paint();

        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setColor(Color.BLACK);

    }


    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //设置发光
        //radius用来定义模糊半径
        //style 发光样式
        //      BlurMaskFilter.Blur.INNER  :内发光
        //      BlurMaskFilter.Blur.SOLID  :外发光
        //      BlurMaskFilter.Blur.NORMAL :内外发光
        //      BlurMaskFilter.Blur.OUTER  :仅显示发光效果
        float radius = 50;
        mPaint.setMaskFilter(new BlurMaskFilter(radius, BlurMaskFilter.Blur.INNER));
        canvas.drawCircle(200, 200, 100, mPaint);

        mPaint.setMaskFilter(new BlurMaskFilter(radius, BlurMaskFilter.Blur.SOLID));
        canvas.drawCircle(420, 200, 100, mPaint);

        mPaint.setMaskFilter(new BlurMaskFilter(radius, BlurMaskFilter.Blur.NORMAL));
        canvas.drawCircle(620, 200, 100, mPaint);

        mPaint.setMaskFilter(new BlurMaskFilter(radius, BlurMaskFilter.Blur.OUTER));
        canvas.drawCircle(820, 200, 100, mPaint);
    }


}

---

7.3.2给图片添加纯色阴影

@SuppressLint("AppCompatCustomView")
public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;
    private Bitmap alphaBitmap;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();

//        mPaint.setAntiAlias(true);
//        mPaint.setDither(true);
//        mPaint.setStyle(Paint.Style.FILL);
//        mPaint.setColor(Color.BLACK);

        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bikabika);
        alphaBitmap = this.bitmap.extractAlpha();

    }


    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int width = bitmap.getWidth();
        int height = width * alphaBitmap.getWidth() / alphaBitmap.getHeight();

        //绘制灰色阴影
        mPaint.setColor(Color.GRAY);
        canvas.drawBitmap(alphaBitmap, null, new Rect(10, 10, width, height), mPaint);


        //绘制黑色阴影
        canvas.translate(0, height);
        mPaint.setColor(Color.BLACK);
        canvas.drawBitmap(alphaBitmap, null, new Rect(10, 10, width, height), mPaint);


        //黑色再加上发光
        canvas.translate(0, height);
        mPaint.setMaskFilter(new BlurMaskFilter(50, BlurMaskFilter.Blur.SOLID));
        canvas.drawBitmap(alphaBitmap, null, new Rect(10, 10, width, height), mPaint);
    }

}

---

给图片画上影子的效果

public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;
    private Bitmap alphaBitmap;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();

//        mPaint.setAntiAlias(true);
//        mPaint.setDither(true);
//        mPaint.setStyle(Paint.Style.FILL);
//        mPaint.setColor(Color.BLACK);

        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bikabika);
        alphaBitmap = this.bitmap.extractAlpha();

    }


    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int width = bitmap.getWidth();
        int height = width * alphaBitmap.getWidth() / alphaBitmap.getHeight();

        //绘制阴影
        mPaint.setColor(Color.GRAY);
        mPaint.setMaskFilter(new BlurMaskFilter(10, BlurMaskFilter.Blur.NORMAL));
        canvas.drawBitmap(alphaBitmap, null, new RectF(20, 20, width, height), mPaint);

        //绘制原图像  也就是盖在阴影上 向左偏移一点
        canvas.translate(-10, -10);
        mPaint.setMaskFilter(null);
        canvas.drawBitmap(bitmap, null, new Rect(20, 20 , width, height), mPaint);
    }

}

---

7.4Shader 与 BitmapShader

着色器

TileMode

  Clamp:用边缘颜色来填充多余空间

  Repeat:重复原图像来填充多余空间

  Mirror:重复使用镜像模式的图像 来填充多余空间

public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bikabika);
        mPaint.setShader(new BitmapShader(bitmap, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));

    }


    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //
        canvas.drawRect(0, 0, getWidth(), getHeight(), mPaint);
    }

}

Repeat:

CLAMP

MIRROR

 

Repeat + Mirror 结合

如果可以固定他的宽高那就好了

需要拿原图尺寸进行设置

canvas.drawRect(0, 0, bitmap.getWidth(), bitmap.getHeight()*2, mPaint);

MIRROR+Repeat

canvas.drawRect(0, 0, bitmap.getWidth()*2, bitmap.getHeight(), mPaint);

---

只画图片的一部分

@SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int width = bitmap.getWidth();
        int height = bitmap.getHeight();

        int left = width / 3;
        int top = height / 3;
        int right = width * 2 / 3;
        int bottom = height * 2 / 3;

        //使用原图尺寸
        canvas.drawRect(left, top, right, bottom, mPaint);
    }

---

望远镜效果:

因为书上和百度各种效果都是重复的所以,我设置了图片只有一个

xml 设置 wrap

public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;


    private int mDx;
    private int mDy;
    private Bitmap mBitmapBg;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog);

    }


    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(bitmap.getWidth(),bitmap.getHeight());
    }

    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mBitmapBg == null) {

            //背景  也就是原图
            mBitmapBg = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);

            //第二画笔
            Canvas canvasBg = new Canvas(mBitmapBg);
            canvasBg.drawBitmap(mBitmapBg, null, new RectF(0, 0, getWidth(), getHeight()), mPaint);
        }


        if (mDx != -1 && mDy != -1) {
            //利用上一次的shader 阴影花一部分来实现望远镜的效果
            mPaint.setShader(new BitmapShader(bitmap, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));
            canvas.drawCircle(mDx, mDy, 150, mPaint);
        }

    }


    @Override
    public boolean onTouchEvent(MotionEvent event) {

        int action = event.getAction();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                mDx = (int) event.getX();
                mDy = (int) event.getY();
                postInvalidate();
                return true;
            case MotionEvent.ACTION_MOVE:
                mDx = (int) event.getX();
                mDy = (int) event.getY();
                break;
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_UP:
                mDx = -1;
                mDy = -1;
                break;
            default:
        }
        postInvalidate();
        return super.onTouchEvent(event);

    }
}

---

看到后边才知道有方法

xml随便写

@SuppressLint("AppCompatCustomView")
public class MyTextView extends TextView {

    private Paint mPaint;
    private Bitmap bitmap;


    private int mDx;
    private int mDy;
    private Bitmap mBitmapBg;

    public MyTextView(Context context) {
        this(context, null);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog);

    }


//    @Override
//    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//        setMeasuredDimension(bitmap.getWidth(),bitmap.getHeight());
//    }

    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mBitmapBg == null) {

            //背景  也就是原图
            mBitmapBg = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);

            //第二画笔
            Canvas canvasBg = new Canvas(mBitmapBg);
            canvasBg.drawBitmap(mBitmapBg, null, new RectF(0, 0, getWidth(), getHeight()), mPaint);
        }


        if (mDx != -1 && mDy != -1) {
            //利用上一次的shader 阴影花一部分来实现望远镜的效果
            Matrix matrix = new Matrix();
            float scaleW = (float) getWidth() / bitmap.getWidth();
            float scaleH = (float) getHeight() / bitmap.getHeight();
            matrix.setScale(scaleW,scaleH);

            BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
            bitmapShader.setLocalMatrix(matrix);
            mPaint.setShader(bitmapShader);

            canvas.drawCircle(mDx, mDy, 150, mPaint);
        }

    }


    @Override
    public boolean onTouchEvent(MotionEvent event) {

        int action = event.getAction();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                mDx = (int) event.getX();
                mDy = (int) event.getY();
                postInvalidate();
                return true;
            case MotionEvent.ACTION_MOVE:
                mDx = (int) event.getX();
                mDy = (int) event.getY();
                break;
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_UP:
                mDx = -1;
                mDy = -1;
                break;
            default:
        }
        postInvalidate();
        return super.onTouchEvent(event);

    }
}

不规则头像

圆形圆角带框

@Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        Matrix matrix = new Matrix();

        float scaleWidth = (float) getWidth() / (bitmap.getWidth());
        float scaleHeight = (float) getHeight() / bitmap.getHeight();
        matrix.setScale(scaleWidth, scaleHeight);

        bitmapShader.setLocalMatrix(matrix);

        mPaint.setShader(bitmapShader);
//        int half = getWidth() / 2;
//        canvas.drawCircle(half, half, half, mPaint);


//        RectF rect = new RectF(30, 30, getWidth() - 30, getHeight() - 30);
//        canvas.drawRoundRect(rect, 30, 30, mPaint);

        //需要边框就加上这个
//        Paint borderpaint = new Paint();
//        borderpaint.setStyle(Paint.Style.STROKE);
//        borderpaint.setStrokeWidth(5);
//        borderpaint.setColor(Color.BLACK);
//
//        canvas.drawRoundRect(rect, 30, 30, borderpaint);

    }

我想加个网络请求的来着,后来做不出来,就是我们现在使用的Bitmap 可以在View:Extends ImageView 的时候,通过getDrawable()获得,需要先判空,然后在转成bitmap 拿着用就行了,总之是做不出来,既然是网络传的图片了,那就用框架把,glide还有结合的Transform

---

7.5.Shader 之LinearGradient

float x0  y0 起始渐变坐标

float x1  y1 结束渐变坐标

colors[]  用于指定渐变的颜色值数组

positions[] 取值0-1 float 表示每种颜色在整条渐变线中的百分比位置

最后一个填充模式 和 上边一样

public class LinearGradientView extends View {

    private Paint mPaint;

    public LinearGradientView(Context context) {
        this(context, null);
    }

    public LinearGradientView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public LinearGradientView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mPaint.setShader(new LinearGradient(0, getHeight() / 2,
                getWidth(), getHeight() / 2,
                0xffff0000, 0xff00ff00,
                Shader.TileMode.CLAMP));

        canvas.drawRect(0, 0, getWidth(), getHeight(), mPaint);

    }
}

int[] colors = {0xffff0000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xff00ffff};
        float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};
        mPaint.setShader(new LinearGradient(0, getHeight() / 2,
                getWidth(), getHeight() / 2,
                colors, pos,
                Shader.TileMode.CLAMP));

        canvas.drawRect(0, 0, getWidth(), getHeight(), mPaint);

如果要斜着那就改起始点和终点

写文字

@Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int[] colors = {0xffff0000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xff00ffff};
        float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};
        mPaint.setShader(new LinearGradient(0, getHeight() / 2,
                getWidth(), getHeight() / 2,
                colors, pos,
                Shader.TileMode.CLAMP));

        mPaint.setTextSize(ConvertUtils.sp2px(24));

        Paint.FontMetrics fm = mPaint.getFontMetrics();
        //文字基准线的下部距离-文字基准线的上部距离 = 文字高度
        float height= fm.descent - fm.ascent;

        canvas.drawText("张无敌嘤嘤嘤", 0, height, mPaint);

    }

从上到下

int[] colors = {0xffff0000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xff00ffff};
        float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};

        mPaint.setTextSize(ConvertUtils.sp2px(24));

        mPaint.setShader(new LinearGradient(getWidth() / 2, 0,
                getWidth() / 2, mPaint.descent() - mPaint.ascent(),
                colors, pos,
                Shader.TileMode.CLAMP));

        canvas.drawText("张无敌嘤嘤嘤", 0, mPaint.descent() - mPaint.ascent(), mPaint);

 这俩种都有填充模式

public class LinearGradientView extends View {

    private Paint mPaint;

    public LinearGradientView(Context context) {
        this(context, null);
    }

    public LinearGradientView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public LinearGradientView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int[] colors = {0xffff0000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xff00ffff};
        float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};

        mPaint.setTextSize(ConvertUtils.sp2px(24));

        Rect minRect = new Rect();
        //通过这个方法得到的位置在上方 需要重新设置Y
        mPaint.getTextBounds("张无敌嘤嘤嘤", 0, "张无敌嘤嘤嘤".length(), minRect);

        int baseLineY = minRect.bottom - minRect.top;
        int minTop = minRect.top + baseLineY;
        int minBottom = minRect.bottom + baseLineY;


        mPaint.setShader(new LinearGradient(getWidth() / 2, minTop,
                getWidth() / 2, minBottom,
                colors, pos,
                Shader.TileMode.REPEAT));

        canvas.drawText("张无敌嘤嘤嘤", 0, baseLineY, mPaint);

    }
}

这个可能有点问题,专门搞了一篇新的,粘的别人的

---

闪光文字效果

@SuppressLint("AppCompatCustomView")
public class ShimmerTextView extends TextView {

    private Paint mPaint;
    private int mLength;

    /**
     * 位移的变化
     */
    private int mDx;
    private LinearGradient mLinearGradient;

    public ShimmerTextView(Context context) {
        this(context, null);
    }

    public ShimmerTextView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public ShimmerTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        mPaint = getPaint();
//        mPaint.setAntiAlias(true);
//        mPaint.setDither(true);

        mLength = (int) mPaint.measureText(getText().toString());
        createAnim(mLength);
        creatLinearGradient(mLength);

    }

    /**
     * 着色
     *
     * @param mLength
     */
    private void creatLinearGradient(int mLength) {

        // 需要注意的  : 开始的颜色 和结束的颜色 最好是一个颜色
        int[] colors = {0xffff0000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xffff0000};
        float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};
        mLinearGradient = new LinearGradient(-mLength, 0, 0, 0, colors, pos, Shader.TileMode.CLAMP);

    }


    /**
     * 绘制路径 文字长度 动画
     *
     * @param mLength
     */
    private void createAnim(int mLength) {
        ValueAnimator mValueAnimator = ValueAnimator.ofInt(0, mLength * 2);
        mValueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mDx = (int) animation.getAnimatedValue();
                postInvalidate();
            }
        });
        mValueAnimator.setRepeatMode(ValueAnimator.RESTART);
        mValueAnimator.setRepeatCount(ValueAnimator.INFINITE);
        mValueAnimator.setDuration(2000);
        mValueAnimator.start();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Matrix mMatrix = new Matrix();
        mMatrix.setTranslate(mDx, 0);
        mLinearGradient.setLocalMatrix(mMatrix);
        mPaint.setShader(mLinearGradient);

        super.onDraw(canvas);
    }
}

双色渐变

public class RadialGradientView extends View {

    private Paint mPaint;
    private RadialGradient mRadialGradient;

    public RadialGradientView(Context context) {
        this(context, null);
    }

    public RadialGradientView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RadialGradientView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        setLayerType(LAYER_TYPE_SOFTWARE, null);
        mPaint = new Paint();


    }

    @SuppressLint("DrawAllocation")
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mRadialGradient == null) {
            int mRadius = getWidth() / 2;

            int[] colors = {0xff000000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xffff0000};
            float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};

            mRadialGradient = new RadialGradient(
                    getWidth() / 2,
                    getHeight() / 2,
                    mRadius,
                    colors,
                    pos,
                    Shader.TileMode.REPEAT
            );

            mPaint.setShader(mRadialGradient);

            canvas.drawCircle(getWidth() / 2, getHeight() / 2, mRadius, mPaint);
        }


    }
}

---

 

if (mRadialGradient == null) {
            int mRadius = getWidth() / 2;

            int[] colors = {0xff000000, 0xff00ff00, 0xffffff00, 0xffffffff, 0xffff0000};
            float[] pos = {0.0f, 0.25f, 0.5f, 0.75f, 1.0f};

            mRadialGradient = new RadialGradient(
                    getWidth() / 2,
                    getHeight() / 2,
                    mRadius,
                    colors,
                    pos,
                    Shader.TileMode.MIRROR
            );

            mPaint.setShader(mRadialGradient);

            canvas.drawRect(0,0,getWidth(),getHeight(), mPaint);
        }

---

CLAMP