xref: /frameworks/base/core/java/com/android/internal/widget/ScrollingTabContainerView.java

/*
 * Copyright (C) 2011 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 com.android.internal.widget;

import android.app.ActionBar;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.text.TextUtils.TruncateAt;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ScrollingTabContainerView extends HorizontalScrollView {
    Runnable mTabSelector;
    private TabClickListener mTabClickListener;

    private LinearLayout mTabLayout;

    int mMaxTabWidth;

    public ScrollingTabContainerView(Context context) {
        super(context);
        setHorizontalScrollBarEnabled(false);
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        setFillViewport(widthMode == MeasureSpec.EXACTLY);

        final int childCount = getChildCount();
        if (childCount > 1 &&
                (widthMode == MeasureSpec.EXACTLY || widthMode == MeasureSpec.AT_MOST)) {
            if (childCount > 2) {
                mMaxTabWidth = (int) (MeasureSpec.getSize(widthMeasureSpec) * 0.4f);
            } else {
                mMaxTabWidth = MeasureSpec.getSize(widthMeasureSpec) / 2;
            }
        } else {
            mMaxTabWidth = -1;
        }

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    public void setTabSelected(int position) {
        if (mTabLayout == null) {
            return;
        }

        final int tabCount = mTabLayout.getChildCount();
        for (int i = 0; i < tabCount; i++) {
            final View child = mTabLayout.getChildAt(i);
            final boolean isSelected = i == position;
            child.setSelected(isSelected);
            if (isSelected) {
                animateToTab(position);
            }
        }
    }

    public void animateToTab(int position) {
        final View tabView = mTabLayout.getChildAt(position);
        if (mTabSelector != null) {
            removeCallbacks(mTabSelector);
        }
        mTabSelector = new Runnable() {
            public void run() {
                final int scrollPos = tabView.getLeft() - (getWidth() - tabView.getWidth()) / 2;
                smoothScrollTo(scrollPos, 0);
                mTabSelector = null;
            }
        };
        post(mTabSelector);
    }

    public void setTabLayout(LinearLayout tabLayout) {
        if (mTabLayout != tabLayout) {
            if (mTabLayout != null) {
                ((ViewGroup) mTabLayout.getParent()).removeView(mTabLayout);
            }
            if (tabLayout != null) {
                addView(tabLayout);
            }
            mTabLayout = tabLayout;
        }
    }

    public LinearLayout getTabLayout() {
        return mTabLayout;
    }

    @Override
    public void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        if (mTabSelector != null) {
            removeCallbacks(mTabSelector);
        }
    }

    private TabView createTabView(ActionBar.Tab tab) {
        final TabView tabView = new TabView(getContext(), tab);
        tabView.setFocusable(true);

        if (mTabClickListener == null) {
            mTabClickListener = new TabClickListener();
        }
        tabView.setOnClickListener(mTabClickListener);
        return tabView;
    }

    public void addTab(ActionBar.Tab tab, boolean setSelected) {
        View tabView = createTabView(tab);
        mTabLayout.addView(tabView, new LinearLayout.LayoutParams(0,
                LayoutParams.MATCH_PARENT, 1));
        if (setSelected) {
            tabView.setSelected(true);
        }
    }

    public void addTab(ActionBar.Tab tab, int position, boolean setSelected) {
        final TabView tabView = createTabView(tab);
        mTabLayout.addView(tabView, position, new LinearLayout.LayoutParams(
                0, LayoutParams.MATCH_PARENT, 1));
        if (setSelected) {
            tabView.setSelected(true);
        }
    }

    public void updateTab(int position) {
        ((TabView) mTabLayout.getChildAt(position)).update();
    }

    public void removeTabAt(int position) {
        if (mTabLayout != null) {
            mTabLayout.removeViewAt(position);
        }
    }

    public void removeAllTabs() {
        if (mTabLayout != null) {
            mTabLayout.removeAllViews();
        }
    }

    private class TabView extends LinearLayout {
        private ActionBar.Tab mTab;
        private TextView mTextView;
        private ImageView mIconView;
        private View mCustomView;

        public TabView(Context context, ActionBar.Tab tab) {
            super(context, null, com.android.internal.R.attr.actionBarTabStyle);
            mTab = tab;

            update();
        }

        @Override
        public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);

            // Re-measure if we went beyond our maximum size.
            if (mMaxTabWidth > 0 && getMeasuredWidth() > mMaxTabWidth) {
                super.onMeasure(MeasureSpec.makeMeasureSpec(mMaxTabWidth, MeasureSpec.EXACTLY),
                        heightMeasureSpec);
            }
        }

        public void update() {
            final ActionBar.Tab tab = mTab;
            final View custom = tab.getCustomView();
            if (custom != null) {
                addView(custom);
                mCustomView = custom;
                if (mTextView != null) mTextView.setVisibility(GONE);
                if (mIconView != null) {
                    mIconView.setVisibility(GONE);
                    mIconView.setImageDrawable(null);
                }
            } else {
                if (mCustomView != null) {
                    removeView(mCustomView);
                    mCustomView = null;
                }

                final Drawable icon = tab.getIcon();
                final CharSequence text = tab.getText();

                if (icon != null) {
                    if (mIconView == null) {
                        ImageView iconView = new ImageView(getContext());
                        LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,
                                LayoutParams.WRAP_CONTENT);
                        lp.gravity = Gravity.CENTER_VERTICAL;
                        iconView.setLayoutParams(lp);
                        addView(iconView, 0);
                        mIconView = iconView;
                    }
                    mIconView.setImageDrawable(icon);
                    mIconView.setVisibility(VISIBLE);
                } else if (mIconView != null) {
                    mIconView.setVisibility(GONE);
                    mIconView.setImageDrawable(null);
                }

                if (text != null) {
                    if (mTextView == null) {
                        TextView textView = new TextView(getContext(), null,
                                com.android.internal.R.attr.actionBarTabTextStyle);
                        textView.setSingleLine();
                        textView.setEllipsize(TruncateAt.END);
                        LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,
                                LayoutParams.WRAP_CONTENT);
                        lp.gravity = Gravity.CENTER_VERTICAL;
                        textView.setLayoutParams(lp);
                        addView(textView);
                        mTextView = textView;
                    }
                    mTextView.setText(text);
                    mTextView.setVisibility(VISIBLE);
                } else if (mTextView != null) {
                    mTextView.setVisibility(GONE);
                    mTextView.setText(null);
                }
            }
        }

        public ActionBar.Tab getTab() {
            return mTab;
        }
    }

    private class TabClickListener implements OnClickListener {
        public void onClick(View view) {
            TabView tabView = (TabView) view;
            tabView.getTab().select();
            final int tabCount = mTabLayout.getChildCount();
            for (int i = 0; i < tabCount; i++) {
                final View child = mTabLayout.getChildAt(i);
                child.setSelected(child == view);
            }
        }
    }
}