自定义个TabLayout

先来个图
两个的
多个的

布局

<com.rsd.library.widget.RTabLayout        android:layout_width="wrap_content"        app:tabTextSize="20sp"        app:tabRadius="10dp"        app:tabBorderColor="#0000ff"        app:tabBorderWidth="1dp"        app:tabMenus="AAA,BBB"        android:layout_height="wrap_content" />

本来说圆角地方都不一样，先是写了一个用path实现的，不过那样计算起来太麻烦。就想改成用xfermode的了，先画个圆角rect，在前面画几个rect就可以了。

代码

public class RTabLayout extends View {    private Paint paint;    private RectF rect;    private RectF rect2;    private Xfermode xfermode;    private String[] menus;    private RectF[] rects;    private float perWidth;    private int index;    private int radius;    private int borderWidth;    private int borderColor;    private int selectColor;    private int unSelectColor;    private int dividedColor;    private int textSize;    private float touchSlop;    private float startX = 0;    private float startY = 0;    private double distance = 0;    private int touchIndex;    private boolean drawLine;    private OnItemClickListener onItemClickListener;    public RTabLayout(Context context) {        this(context, null);    }    public RTabLayout(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public RTabLayout(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.RTabLayout, defStyleAttr, 0);        radius = array.getDimensionPixelSize(R.styleable.RTabLayout_tabRadius, 30);        borderWidth = array.getDimensionPixelSize(R.styleable.RTabLayout_tabBorderWidth, 5);        borderColor = array.getColor(R.styleable.RTabLayout_tabBorderColor, 0xffffffff);        selectColor = array.getColor(R.styleable.RTabLayout_tabSelectColor, 0xffffffff);        unSelectColor = array.getColor(R.styleable.RTabLayout_tabUnSelectColor, 0xffffa417);        dividedColor = array.getColor(R.styleable.RTabLayout_tabDividedColor, 0xffffffff);        textSize = array.getDimensionPixelSize(R.styleable.RTabLayout_tabTextSize, 30);        String menu = array.getString(R.styleable.RTabLayout_tabMenus);        if (menu == null) {            menus = new String[]{"A", "B"};        } else {            menus = menu.split(",");        }        setMenus(menus);        array.recycle();        init();    }    private void init() {        touchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();        paint = new Paint(Paint.ANTI_ALIAS_FLAG);        paint.setTextSize(textSize);        rect = new RectF();        rect2 = new RectF();        xfermode = new PorterDuffXfermode(PorterDuff.Mode.SRC_IN);    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        rect.set(0, 0, w, h);        rect2.set(borderWidth, borderWidth, w - borderWidth, h - borderWidth);        perWidth = w / rects.length;        for (int i = 0; i < rects.length; i++) {            rects[i] = new RectF(i * perWidth, 0, (i + 1) * perWidth, h);        }    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        int widthSize = MeasureSpec.getSize(widthMeasureSpec);        int widthMode = MeasureSpec.getMode(widthMeasureSpec);        int heightSize = MeasureSpec.getSize(heightMeasureSpec);        int heightMode = MeasureSpec.getMode(heightMeasureSpec);        int w = 0, h = 0;        if (widthMode == MeasureSpec.EXACTLY) {            w = widthSize;        } else {            int maxLen = 0;            for (int i = 0; i < menus.length; i++) {                if (menus[i].length() > maxLen) {                    maxLen = menus[i].length();                }            }            w = textSize * (maxLen + 2) * menus.length;        }        if (heightMode == MeasureSpec.EXACTLY) {            h = heightSize;        } else {            h = textSize * 2;        }        setMeasuredDimension(w, h);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        drawBg(canvas);        drawLine(canvas);        drawText(canvas);    }    private void drawBg(Canvas canvas) {        paint.setColor(borderColor);        canvas.drawRoundRect(rect, radius, radius, paint);        int layer = canvas.saveLayer(rect, paint, Canvas.ALL_SAVE_FLAG);        canvas.drawRoundRect(rect2, radius, radius, paint);        paint.setXfermode(xfermode);        for (int i = 0; i < rects.length; i++) {            if (i == index) {                paint.setColor(selectColor);            } else {                paint.setColor(unSelectColor);            }            canvas.drawRect(rects[i], paint);        }        paint.setXfermode(null);        canvas.restoreToCount(layer);    }    private void drawLine(Canvas canvas) {        if (drawLine) {            return;        }        paint.setColor(dividedColor);        for (int i = 1; i < menus.length; i++) {            if (i == index || i == index + 1) {                continue;            }            float x = perWidth * i;            float h = rect.height();            canvas.drawLine(x, h * 0.2f, x, h * 0.8f, paint);        }        drawLine = true;    }    private void drawText(Canvas canvas) {        float x;        float y;        for (int i = 0; i < menus.length; i++) {            if (i == index) {                paint.setColor(unSelectColor);            } else {                paint.setColor(selectColor);            }            x = perWidth * (i + 0.5f) - paint.measureText(menus[i]) / 2;            y = rect.height() / 2 - (paint.descent() + paint.ascent()) / 2;            canvas.drawText(menus[i], x, y, paint);        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                startX = event.getX();                startY = event.getY();                touchIndex = (int) (startX / perWidth);                break;            case MotionEvent.ACTION_MOVE:                distance = Math.sqrt((event.getX() - startX) * (event.getX() - startX) + (event.getY() - startY) * (event.getY() - startY));                break;            case MotionEvent.ACTION_UP:                if (distance < touchSlop) {                    setCurrent(touchIndex);                    if (onItemClickListener != null) {                        onItemClickListener.onItemClick(touchIndex);                    }                }                distance = 0;                break;        }        return true;    }    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {        this.onItemClickListener = onItemClickListener;    }    public void setMenus(String[] menus) {        this.menus = menus;        rects = new RectF[menus.length];    }    public void setCurrent(int position) {        this.index = position;        invalidate();    }    public interface OnItemClickListener {        void onItemClick(int position);    }}