design/src/android/support/design/internal/BottomNavigationItemView.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.support.design.internal;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.ColorStateList;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.design.R;
import android.support.v4.content.ContextCompat;
import android.support.v4.graphics.drawable.DrawableCompat;
import android.support.v4.view.animation.LinearOutSlowInInterpolator;
import android.support.v7.view.menu.MenuItemImpl;
import android.support.v7.view.menu.MenuView;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.LayoutInflater;
import android.view.ViewPropertyAnimator;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.TextView;

/**
 * @hide
 */
public class BottomNavigationItemView extends FrameLayout implements MenuView.ItemView {
    public static final int INVALID_ITEM_POSTION = -1;

    private static final int[] CHECKED_STATE_SET = { android.R.attr.state_checked };
    private static final long ACTIVE_ANIMATION_DURATION_MS = 115L;

    private final float mShiftAmount;
    private final float mScaleUpFactor;
    private final float mScaleDownFactor;
    private final float mInactiveLabelSize;
    private final float mActiveLabelSize;

    private ImageView mIcon;
    private TextView mLabel;
    private int mItemPosition = INVALID_ITEM_POSTION;

    private MenuItemImpl mItemData;

    private ColorStateList mIconTint;

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

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

    public BottomNavigationItemView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mInactiveLabelSize =
                getResources().getDimension(R.dimen.design_bottom_navigation_text_size);
        mActiveLabelSize =
                getResources().getDimension(R.dimen.design_bottom_navigation_active_text_size);
        mShiftAmount = mInactiveLabelSize - mActiveLabelSize;
        mScaleUpFactor = mActiveLabelSize / mInactiveLabelSize;
        mScaleDownFactor = mInactiveLabelSize / mActiveLabelSize;

        LayoutInflater.from(context).inflate(R.layout.design_bottom_navigation_item, this, true);
        setBackgroundResource(R.drawable.design_bottom_navigation_item_background);
        mIcon = (ImageView) findViewById(R.id.icon);
        mLabel = (TextView) findViewById(R.id.label);
    }

    @Override
    public void initialize(MenuItemImpl itemData, int menuType) {
        mItemData = itemData;
        setCheckable(itemData.isCheckable());
        setChecked(itemData.isChecked(), false);
        setEnabled(itemData.isEnabled());
        setIcon(itemData.getIcon());
        setTitle(itemData.getTitle());
        setId(itemData.getItemId());
    }

    public void setItemPosition(int position) {
        mItemPosition = position;
    }

    public int getItemPosition() {
        return mItemPosition;
    }

    @Override
    public MenuItemImpl getItemData() {
        return mItemData;
    }

    @Override
    public void setTitle(CharSequence title) {
        mLabel.setText(title);
    }

    @Override
    public void setCheckable(boolean checkable) {
        refreshDrawableState();
    }

    @Override
    public void setChecked(boolean checked) {
        setChecked(checked, true);
    }

    public void setChecked(boolean checked, boolean animate) {
        mItemData.setChecked(checked);

        mLabel.setTextSize(TypedValue.COMPLEX_UNIT_PX,
                checked ? mActiveLabelSize : mInactiveLabelSize);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR1) {
            if (animate) {
                animate(checked);
            } else {
                mIcon.setTranslationY(checked ? mShiftAmount : 0f);
            }
        }

        refreshDrawableState();
    }

    @Override
    public void setEnabled(boolean enabled) {
        super.setEnabled(enabled);
        mLabel.setEnabled(enabled);
        mIcon.setEnabled(enabled);
    }

    @Override
    public int[] onCreateDrawableState(final int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (mItemData != null && mItemData.isCheckable() && mItemData.isChecked()) {
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        }
        return drawableState;
    }

    @Override
    public void setShortcut(boolean showShortcut, char shortcutKey) {
    }

    @Override
    public void setIcon(Drawable icon) {
        if (icon != null) {
            Drawable.ConstantState state = icon.getConstantState();
            icon = DrawableCompat.wrap(state == null ? icon : state.newDrawable()).mutate();
            DrawableCompat.setTintList(icon, mIconTint);
        }
        mIcon.setImageDrawable(icon);
    }

    @Override
    public boolean prefersCondensedTitle() {
        return false;
    }

    @Override
    public boolean showsIcon() {
        return true;
    }

    public void setIconTintList(ColorStateList tint) {
        mIconTint = tint;
        if (mItemData != null) {
            // Update the icon so that the tint takes effect
            setIcon(mItemData.getIcon());
        }
    }

    public void setTextColor(ColorStateList color) {
        mLabel.setTextColor(color);
    }

    public void setItemBackground(int background) {
        Drawable backgroundDrawable = background == 0
                ? null : ContextCompat.getDrawable(getContext(), background);
        setBackgroundDrawable(backgroundDrawable);
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
    private void animate(final boolean active) {
        final float startingTextScale = active ? mScaleDownFactor : mScaleUpFactor;

        // Grow or shrink the text of the tab.
        mLabel.setScaleX(startingTextScale);
        mLabel.setScaleY(startingTextScale);
        ViewPropertyAnimator textAnimator = mLabel.animate()
                .setDuration(ACTIVE_ANIMATION_DURATION_MS)
                .setInterpolator(new LinearOutSlowInInterpolator())
                .scaleX(1f)
                .scaleY(1f);

        ViewPropertyAnimator translationAnimation = mIcon.animate()
                .setDuration(ACTIVE_ANIMATION_DURATION_MS)
                .setInterpolator(new LinearOutSlowInInterpolator())
                .translationY(active ? mShiftAmount : 0);

        textAnimator.start();
        translationAnimation.start();
    }
}