控件使用 就不在此啰嗦了膀估，很簡單。

• 分析原因
  1.BottomNavigationView耻讽，item大于3個(gè)的顯示奇怪的情況察纯，這個(gè)移動(dòng)動(dòng)畫幾乎都是不想要的。
  首先在BottomNavigationMenuView中针肥，有一個(gè)全局變量：mShiftingMode饼记，然后在創(chuàng)建Menu的時(shí)候buildMenuView()

public void buildMenuView() {
          ...
          mShiftingMode = mMenu.size() > 3;
          ...
}

當(dāng)size>3時(shí)候，設(shè)為ture慰枕。
然后在BottomNavigationItemView具则，設(shè)置check的時(shí)候：

@Override
    public void setChecked(boolean checked) {
        ViewCompat.setPivotX(mLargeLabel, mLargeLabel.getWidth() / 2);
        ViewCompat.setPivotY(mLargeLabel, mLargeLabel.getBaseline());
        ViewCompat.setPivotX(mSmallLabel, mSmallLabel.getWidth() / 2);
        ViewCompat.setPivotY(mSmallLabel, mSmallLabel.getBaseline());
        if (mShiftingMode) {
            if (checked) {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
                iconParams.topMargin = mDefaultMargin;
                mIcon.setLayoutParams(iconParams);
                mLargeLabel.setVisibility(VISIBLE);
                ViewCompat.setScaleX(mLargeLabel, 1f);
                ViewCompat.setScaleY(mLargeLabel, 1f);
            } else {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER;
                iconParams.topMargin = mDefaultMargin;
                mIcon.setLayoutParams(iconParams);
                mLargeLabel.setVisibility(INVISIBLE);
                ViewCompat.setScaleX(mLargeLabel, 0.5f);
                ViewCompat.setScaleY(mLargeLabel, 0.5f);
            }
            mSmallLabel.setVisibility(INVISIBLE);
        } else {
            if (checked) {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
                iconParams.topMargin = mDefaultMargin + mShiftAmount;
                mIcon.setLayoutParams(iconParams);
                mLargeLabel.setVisibility(VISIBLE);
                mSmallLabel.setVisibility(INVISIBLE);

                ViewCompat.setScaleX(mLargeLabel, 1f);
                ViewCompat.setScaleY(mLargeLabel, 1f);
                ViewCompat.setScaleX(mSmallLabel, mScaleUpFactor);
                ViewCompat.setScaleY(mSmallLabel, mScaleUpFactor);
            } else {
                LayoutParams iconParams = (LayoutParams) mIcon.getLayoutParams();
                iconParams.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
                iconParams.topMargin = mDefaultMargin;
                mIcon.setLayoutParams(iconParams);
                mLargeLabel.setVisibility(INVISIBLE);
                mSmallLabel.setVisibility(VISIBLE);

                ViewCompat.setScaleX(mLargeLabel, mScaleDownFactor);
                ViewCompat.setScaleY(mLargeLabel, mScaleDownFactor);
                ViewCompat.setScaleX(mSmallLabel, 1f);
                ViewCompat.setScaleY(mSmallLabel, 1f);
            }
        }

        refreshDrawableState();
    }

然后會(huì)根據(jù)shiftMode的值執(zhí)行不同的邏輯，所以產(chǎn)生了這個(gè)動(dòng)畫效果具帮。

官方?jīng)]有對(duì)這個(gè) 字段暴露出修改的方法博肋，所以可以通過反射的方式低斋，間接修改這個(gè)字段。

public class BottomNavigationViewHelper {
    public static void disableShiftMode(BottomNavigationView view) {
        BottomNavigationMenuView menuView = (BottomNavigationMenuView) view.getChildAt(0);
        try {
            Field shiftingMode = menuView.getClass().getDeclaredField("mShiftingMode");
            shiftingMode.setAccessible(true);
            shiftingMode.setBoolean(menuView, false);
            shiftingMode.setAccessible(false);
            for (int i = 0; i < menuView.getChildCount(); i++) {
                BottomNavigationItemView item = (BottomNavigationItemView) menuView.getChildAt(i);
                //noinspection RestrictedApi
                item.setShiftingMode(false);
                // set once again checked value, so view will be updated
                //noinspection RestrictedApi
                item.setChecked(item.getItemData().isChecked());
            }
        } catch (Exception e) {
            
        } 
    }
}

最后在使用BottomNavigationView的地方 調(diào)用：

bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottomview);
// 去除動(dòng)畫效果
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);

最后運(yùn)行起來束昵，移動(dòng)動(dòng)畫消除了，還附帶了一個(gè)很細(xì)微的抖動(dòng)動(dòng)畫葛峻，超贊的有木有锹雏。