最近看到很多app中間icon凸起沈跨，比如小米商城、一淘诀紊、菜鳥等等谒出，正好也在復(fù)習(xí)自定view的知識，就寫了這篇文章邻奠。

git地址笤喳，如果對您有幫助，麻煩點(diǎn)個贊~ 謝謝~

框架設(shè)計思想

• 功能模塊 高內(nèi)聚低耦合
• 面向接口（接口先行）
• 要易于擴(kuò)展和維護(hù)（面向未來）

需求分析

• 可以提供提供通用的API
• 支持透明度和底部透出
• 支持Tab中間高度超過碌宴，凸起布局效果
• 支持iconfont和Bitmap和url

小米商城效果

模仿效果

實現(xiàn)思路
通過resetHeight達(dá)到底部凸起效果

public class TabBottomG extends RelativeLayout implements ITabG<TabBottomInfo<?>> {

    private TabBottomInfo<?> tabInfo;
    private ImageView tabImageView;
    private TextView tabIconView;
    private TextView tabNameView;

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

    public TabBottomG(Context context,AttributeSet attrs) {
        this(context,attrs,0);
    }

    public TabBottomG(Context context,AttributeSet attrs,int defStyleAttr) {
        super(context,attrs,defStyleAttr);
        init();
    }

    private void init() {
        LayoutInflater.from(getContext()).inflate(R.layout.tab_bottom_g, this);
        tabImageView = findViewById(R.id.iv_image);
        tabIconView = findViewById(R.id.tv_icon);
        tabNameView = findViewById(R.id.tv_name);
    }


    @Override
    public void setTabInfoG(@NonNull @NotNull TabBottomInfo<?> tabBottomInfo) {
        this.tabInfo = tabBottomInfo;
        inflateInfo(false, true);
    }

    public TabBottomInfo getTabInfo() {
        return tabInfo;
    }

    public ImageView getTabImageView() {
        return tabImageView;
    }

    public TextView getTabIconView() {
        return tabIconView;
    }

    public TextView getTabNameView() {
        return tabNameView;
    }

    /**
     * 改變某個tab的高度
     *
     * @param height
     */
    @Override
    public void resetHeight(@Px int height) {
        ViewGroup.LayoutParams layoutParams = getLayoutParams();
        layoutParams.height = height;
        setLayoutParams(layoutParams);
        getTabNameView().setVisibility(View.GONE);
    }

    private void inflateInfo(boolean selected, boolean init) {
        if (tabInfo.tabType == TabBottomInfo.TabType.ICON) {
            if (init) {
                tabImageView.setVisibility(GONE);
                tabIconView.setVisibility(VISIBLE);
                Typeface typeface = Typeface.createFromAsset(getContext().getAssets(), tabInfo.iconFont);
                tabIconView.setTypeface(typeface);
                if (!TextUtils.isEmpty(tabInfo.name)) {
                    tabNameView.setText(tabInfo.name);
                }
            }

            if (selected) {
                tabIconView.setText(TextUtils.isEmpty(tabInfo.selectedIconName) ? tabInfo.defaultIconName : tabInfo.selectedIconName);
                tabIconView.setTextColor(getTextColor(tabInfo.tintColor));
                tabNameView.setTextColor(getTextColor(tabInfo.tintColor));
            } else {
                tabIconView.setText(tabInfo.defaultIconName);
                tabIconView.setTextColor(getTextColor(tabInfo.defaultColor));
                tabNameView.setTextColor(getTextColor(tabInfo.defaultColor));
            }

        } else if (tabInfo.tabType == TabBottomInfo.TabType.BITMAP) {
            if (init) {
                tabImageView.setVisibility(VISIBLE);
                tabIconView.setVisibility(GONE);
                if (!TextUtils.isEmpty(tabInfo.name)) {
                    tabNameView.setText(tabInfo.name);
                }
            }
            if (selected) {
                //tabImageView.setImageBitmap(tabInfo.selectedBitmap);
                //tabImageView.setImageResource(R.drawable.luoxi);
                tabImageView.setImageResource(tabInfo.selectedResId);
            } else {
                //tabImageView.setImageBitmap(tabInfo.defaultBitmap);
                tabImageView.setImageResource(tabInfo.defaultResId);
            }
        }
    }

    @Override
    public void onTabSelectedChange(int index,@Nullable @org.jetbrains.annotations.Nullable TabBottomInfo<?> prevInfo,@NonNull @NotNull TabBottomInfo<?> nextInfo) {
        if (prevInfo != tabInfo && nextInfo != tabInfo || prevInfo == nextInfo) {
            return;
        }
        if (prevInfo == tabInfo) {
            inflateInfo(false, false);
        } else {
            inflateInfo(true, false);
        }
    }

    /**
     * color可傳string或int的方法
     */
    @ColorInt
    private int getTextColor(Object color) {
        if (color instanceof String) {
            return Color.parseColor((String) color);
        } else {
            return (int) color;
        }
    }
}

外部容器封裝

/**
 * Desc：
 * author：Christiano
 * 1. 透明度和底部透出杀狡，列表可渲染高度問題
 * 2. 中間高度超過，凸起布局
 */
public class TabBottomLayoutG extends FrameLayout implements ITabLayout<TabBottomG,TabBottomInfo<?>> {
    private List<OnTabSelectedListener<TabBottomInfo<?>>> tabSelectedChangeListeners = new ArrayList<>();
    private TabBottomInfo<?> selectedInfo;
    private float bottomAlpha = 1f;
    //TabBottom高度
    private static float tabBottomHeight = 50;
    //TabBottom的頭部線條高度
    private float bottomLineHeight = 0.5f;
    //TabBottom的頭部線條顏色
    private String bottomLineColor = "#dfe0e1";
    private List<TabBottomInfo<?>> infoList;
    //底部背景色
    private int bottomBgColor = Color.WHITE;

    private static final String TAG_TAB_BOTTOM = "TAG_TAB_BOTTOM";

    public TabBottomLayoutG(@NonNull Context context) {
        this(context, null);
    }

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

    public TabBottomLayoutG(@NonNull Context context,@Nullable AttributeSet attrs,int defStyleAttr) {
        super(context,attrs,defStyleAttr);
    }


    @Override
    public void inflateInfo(@NonNull @NotNull List<TabBottomInfo<?>> infoList) {
        if (infoList.isEmpty()) {
            return;
        }
        this.infoList = infoList;
        // 移除之前已經(jīng)添加的View
        for (int i = getChildCount() - 1; i > 0; i--) {
            removeViewAt(i);
        }
        selectedInfo = null;
        addBackground();
        //清除之前添加的HiTabBottom listener贰镣，Tips：Java foreach remove問題
        Iterator<OnTabSelectedListener<TabBottomInfo<?>>> iterator = tabSelectedChangeListeners.iterator();
        while (iterator.hasNext()) {
            if (iterator.next() instanceof TabBottomG) {
                iterator.remove();
            }
        }
        int height = DisplayUtil.dp2px(tabBottomHeight, getResources());
        FrameLayout ll = new FrameLayout(getContext());
        int width = DisplayUtil.getDisplayWidthInPx(getContext()) / infoList.size();
        ll.setTag(TAG_TAB_BOTTOM);
        for (int i = 0; i < infoList.size(); i++) {
            final TabBottomInfo<?> info = infoList.get(i);
            //Tips：為何不用LinearLayout：當(dāng)動態(tài)改變child大小后Gravity.BOTTOM會失效
            LayoutParams params = new LayoutParams(width, height);
            params.gravity = Gravity.BOTTOM;
            params.leftMargin = i * width;

            TabBottomG tabBottom = new TabBottomG(getContext());
            tabSelectedChangeListeners.add(tabBottom);
            tabBottom.setTabInfoG(info);
            ll.addView(tabBottom, params);
            tabBottom.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    onSelected(info);
                }
            });
        }
        LayoutParams flPrams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
        flPrams.gravity = Gravity.BOTTOM;
        addBottomLine();
        addView(ll, flPrams);

        fixContentView();

    }

    @Override
    public void addTabSelectedChangeListener(OnTabSelectedListener<TabBottomInfo<?>> listener) {
        tabSelectedChangeListeners.add(listener);
    }

    public void setTabAlpha(float alpha) {
        this.bottomAlpha = alpha;
    }

    public void setBottomBgColor(int color) {
        this.bottomBgColor = color;
    }

    public void setTabHeight(float tabHeight) {
        this.tabBottomHeight = tabHeight;
    }

    public void setBottomLineHeight(float bottomLineHeight) {
        this.bottomLineHeight = bottomLineHeight;
    }

    public void setBottomLineColor(String bottomLineColor) {
        this.bottomLineColor = bottomLineColor;
    }

    @Override
    public TabBottomG findTab(@NonNull @NotNull TabBottomInfo<?> info) {
        ViewGroup ll = findViewWithTag(TAG_TAB_BOTTOM);
        for (int i = 0; i < ll.getChildCount(); i++) {
            View child = ll.getChildAt(i);
            if (child instanceof TabBottomG) {
                TabBottomG tab = (TabBottomG) child;
                if (tab.getTabInfo() == info) {
                    return tab;
                }
            }
        }
        return null;
    }

    @Override
    public void defaultSelected(@NonNull @NotNull TabBottomInfo<?> defaultInfo) {
        onSelected(defaultInfo);
    }

    private void onSelected(@NonNull TabBottomInfo<?> nextInfo) {
        for (OnTabSelectedListener<TabBottomInfo<?>> listener : tabSelectedChangeListeners) {
            listener.onTabSelectedChange(infoList.indexOf(nextInfo), selectedInfo, nextInfo);
        }
        this.selectedInfo = nextInfo;
    }

    private void addBottomLine() {
        View bottomLine = new View(getContext());
        bottomLine.setBackgroundColor(Color.parseColor(bottomLineColor));

        LayoutParams bottomLineParams =
                new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, DisplayUtil.dp2px(bottomLineHeight, getResources()));
        bottomLineParams.gravity = Gravity.BOTTOM;
        bottomLineParams.bottomMargin = DisplayUtil.dp2px(tabBottomHeight - bottomLineHeight, getResources());
        addView(bottomLine, bottomLineParams);
        bottomLine.setAlpha(bottomAlpha);
    }

    private void addBackground() {
        View view = LayoutInflater.from(getContext()).inflate(R.layout.bottom_layout_bg, null);

        LayoutParams params =
                new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, DisplayUtil.dp2px(tabBottomHeight, getResources()));
        params.gravity = Gravity.BOTTOM;
        addView(view, params);
        view.setAlpha(bottomAlpha);
        view.setBackgroundColor(bottomBgColor);

    }

    /**
     * 修復(fù)內(nèi)容區(qū)域的底部Padding
     */
    private void fixContentView() {
        if (!(getChildAt(0) instanceof ViewGroup)) {
            return;
        }
        ViewGroup rootView = (ViewGroup) getChildAt(0);
        ViewGroup targetView = ViewUtil.findTypeView(rootView, RecyclerView.class);
        if (targetView == null) {
            //查找srcollview
            targetView = ViewUtil.findTypeView(rootView, ScrollView.class);
        }
        if (targetView == null) {
            //查找AbsListView（是gridview和listview子類）
            targetView = ViewUtil.findTypeView(rootView, AbsListView.class);
        }
        if (targetView != null) {
            targetView.setPadding(0, 0, 0, DisplayUtil.dp2px(tabBottomHeight, getResources()));
            targetView.setClipToPadding(false);
        }
    }

}