android自定义TabHost扩展控件TabView

最近项目中需要实现TabHost,鉴于TabHost不能实现想要的功能,所以决定自定义一个控件,用于替代TabHost,实现拖拽,Tab之间的替换等功能.刚整合了一份简单的代码,第一次发表文章,写的不好的地方,望见谅.废话不多说,贴代码

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代码实现共2个类,TabView和Tab

TabView的绘制方法.

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.translate(tabViewStart_x, 0);
        if (tabs == null)
            return;
        if (!initTabRegion) {
            // 给每个Tab分配区域.
            initTabRegion();
            // 设置第一个Tab选中.

 

setTabFocus(tabs.get(0)); } for (Tab tab : tabs) { if (currentTab != tab || !scrollTab) { // 调用每个Tab的draw方法. tab.draw(canvas); } } if (currentTab != null && scrollTab) { // 移动状态时调用. currentTab.drawMovement(canvas, currentTabStart_x + currentTabMove_x); } canvas.translate(-tabViewStart_x, 0); tempRegion.set(0, 55, currentTabStart_x + getWidth(), 60); canvas.drawBitmap(TabUtil.tab_band, null, tempRegion, null); }

 TabView的事件

 @Override
    public boolean onTouchEvent(MotionEvent event) {
        event.setLocation(event.getX() - tabViewStart_x, event.getY());
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            // 获取选中Tab.
            currentTab = getCurrentTab(event, false);
            if (currentTab != null) {
                longPress = true;
                // 长按事件.
                onLongPress();
                currentTabStart_x = currentTab.getRegion().left;
                currentTabMove_x = 0;
                setTabFocus(currentTab);
            }
            x = (int) event.getX();
            y = (int) event.getY();
            break;
        case MotionEvent.ACTION_MOVE:
            if (Math.abs(event.getX() - x) > 10 || Math.abs(event.getY() - y) >10) {
                longPress = false;
            }
            if (currentTab == null) {
                break;
            }
            if (scrollTab) {
                Tab tab = getCurrentTab(event, true);
                // 长按Tab移动,实现Tab之间的替换.
                if (tab != null && currentTab != tab) {
                    int tabID = tabs.indexOf(tab);
                    int currentTabID = tabs.indexOf(currentTab);
                    tabs.set(tabID, currentTab);
                    tabs.set(currentTabID, tab);
                    initTabRegion();
                }
            } else {
                // 整个View的拖拽.
                tabViewStart_x += (int) event.getX() - x;
            }
            currentTabMove_x = (int) event.getX() - x;
            break;
        case MotionEvent.ACTION_UP:
            longPress = false;
            scrollTab = false;
            if (task != null) {
                task.cancel();
            }
            // 拖拽松开时开启一个Timer,实现自定义动画效果.
            task = new TimerTask() {
                @Override
                public void run() {
                    animateHandler.sendEmptyMessage(1);
                }
            };
            if (tabViewStart_x > 0) {
                start = 0;
                timer.schedule(task, 0, 20);
            }
            break;
        }
        event.setLocation(event.getX() + tabViewStart_x, event.getY());
        invalidate();
        return true;
    }

Handler接受Timer发送的消息.

    private Handler animateHandler = new Handler() {
        public void dispatchMessage(android.os.Message msg) {
            // 自定义动画效果.
            startAnimation(600);
            if (tabViewStart_x <= 0 && task != null) {
                task.cancel();
                tabViewStart_x = 0;
            }
            invalidate();
        };
    };

Tab的绘制方法.

    public void draw(Canvas canvas) {
        canvas.setDrawFilter(pdf);
        if (sheetTabAdd) {
            this.tab_left = TabUtil.tab_off_left;
            this.tab_mid = TabUtil.tab_off_mid;
            this.tab_right = TabUtil.tab_off_right;
            drawBitmap(canvas, region, null);
        } else {
            if (thisFocus) {
                this.tab_left = TabUtil.tab_on_left;
                this.tab_mid = TabUtil.tab_on_mid;
                this.tab_right = TabUtil.tab_on_right;
            } else {
                this.tab_left = TabUtil.tab_off_left;
                this.tab_mid = TabUtil.tab_off_mid;
                this.tab_right = TabUtil.tab_off_right;
            }
            // 绘制图片.
            drawBitmap(canvas, region, null);
            // 绘制文字.
            canvas.drawText(title, region.left + 45, region.bottom - 12, textPaint);
        }
    }

Tab移动时的绘制方法.

    public void drawMovement(Canvas canvas, int currentMove_x) {
        canvas.setDrawFilter(pdf);
        if (paint == null) {
            paint = new Paint();
            paint.setAlpha(200);
        }
        if (moveRegion == null) {
            moveRegion = new Rect(currentMove_x, region.top, currentMove_x + getTabWidth(), region.bottom);
        } else {
            moveRegion.left = currentMove_x;
            moveRegion.right = currentMove_x + getTabWidth();
        }
        drawBitmap(canvas, moveRegion, paint);
        canvas.drawText(title, currentMove_x + 45, region.bottom - 12, textPaint);
    }