BottomNavigationView解决三个限制记录

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在查看lottie动画库的代码时发现它的底部是利用BottomNavigationView实现的底部导航栏，但是却不受3个的限制（控件超过三个就会进行处理，隐藏除选中外的文字并缩小），还保留了控件原本3个以内的效果，这里我就把它的代码贴出来

效果

  • BottomNavigationView的结构，清楚了控件的构成就容易解决问题了
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//从上倒下包含
BottomNavigationView 
BottomNavigationMenu 
BottomNavigationItemView
  • lottie中代码使用kotlin写的
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private val TAG = NoShiftBottomNavigationView::class.java.name
class NoShiftBottomNavigationView @JvmOverloads constructor(
        context: Context,
        attrs: AttributeSet? = null,
        defStyleAttr: Int = 0
) : BottomNavigationView(context, attrs, defStyleAttr) {
    override fun onViewAdded(child: View?) {
        super.onViewAdded(child)
        removeShiftAnimation()
    }
    @SuppressLint("RestrictedApi")
    private fun removeShiftAnimation() {
        val menuView = getChildAt(0) as BottomNavigationMenuView
        try {
            menuView::class.java.getDeclaredField("mShiftingMode").apply {
                isAccessible = true
                setBoolean(menuView, false)
                isAccessible = false
            }
            menuView.children
                    .map { it as BottomNavigationItemView }
                    .forEach {
                        it.setShiftingMode(false)
                        it.setChecked(it.itemData.isChecked)
                    }
        } catch (e: NoSuchFieldException) {
            Log.e(TAG, "Unable to get shift mode field", e)
        } catch (e: IllegalAccessException) {
            Log.e(TAG, "Unable to change value of shift mode", e)
        }
    }
}
  • 我也写了一份java的(最近正好在学koltin)
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public class NoShiftBottomNavigationView extends BottomNavigationView {
    private String TAG = getClass().getSimpleName();
    
    public NoShiftBottomNavigationView(Context context) {
        this(context,null);
    }
    public NoShiftBottomNavigationView(Context context, AttributeSet attrs) {
        super(context, attrs,0);
    }
    public NoShiftBottomNavigationView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    @Override
    public void onViewAdded(View child) {
        super.onViewAdded(child);
        //当底部导航菜单被添加，去除系统的效果
        removeShiftAnimation();
    }
    @SuppressLint("RestrictedApi")
    private void removeShiftAnimation() {
        BottomNavigationMenuView menuView = (BottomNavigationMenuView) getChildAt(0);
        try {
            //利用反射获取到mShiftingMode属性，设置为false不需要shift动画效果(控制移动动画)
            Field shiftingMode = menuView.getClass().getDeclaredField("mShiftingMode");
            //忽略该属性的访问显示
            shiftingMode.setAccessible(true);
            shiftingMode.setBoolean(menuView,false);
            shiftingMode.setAccessible(false);
            //取消每一个子菜单的shift动画效果（控制文字是否显示隐藏）
            for (int i = 0; i < menuView.getChildCount(); i++) {
                BottomNavigationItemView itemView  = (BottomNavigationItemView) menuView.getChildAt(i);
                itemView.setShiftingMode(false);
                itemView.setChecked(itemView.getItemData().isChecked());
            }
        } catch (NoSuchFieldException e) {
            Log.e(TAG, "Unable to get shift mode field", e);
        } catch (IllegalAccessException e) {
            Log.e(TAG, "Unable to change value of shift mode", e);
        }
    }
}

  • 注意

    如果混淆了design包记得忽略混淆该属性，防止混淆后属性名变化，反射无法找到该属性，导致异常

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-keepclassmembers class android.support.design.internal.BottomNavigationMenuView { 
    boolean mShiftingMode; 
}