Java tutorial
/* * Copyright (C) 2013 Andreas Stuetz <andreas.stuetz@gmail.com>, modified by John Persano 2015 * * 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.github.johnpersano.supertoasts.demo.views; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Paint.Style; import android.graphics.Typeface; import android.os.Build; import android.os.Parcel; import android.os.Parcelable; import android.support.annotation.NonNull; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.util.AttributeSet; import android.util.DisplayMetrics; import android.util.TypedValue; import android.view.Gravity; import android.view.View; import android.view.ViewTreeObserver.OnGlobalLayoutListener; import android.widget.HorizontalScrollView; import android.widget.ImageButton; import android.widget.LinearLayout; import android.widget.TextView; import com.github.johnpersano.supertoasts.demo.R; import java.util.Locale; @SuppressWarnings("deprecation") public class TabStrip extends HorizontalScrollView { public interface IconTabProvider { int getPageIconResId(int position); } // @formatter:off private static final int[] ATTRS = new int[] { android.R.attr.textSize, android.R.attr.textColor }; // @formatter:on private final LinearLayout.LayoutParams defaultTabLayoutParams; private final LinearLayout.LayoutParams expandedTabLayoutParams; private final PageListener pageListener = new PageListener(); private OnPageChangeListener delegatePageListener; private final LinearLayout tabsContainer; private ViewPager pager; private int tabCount; private int currentPosition = 0; private float currentPositionOffset = 0f; private final Paint rectPaint; private int indicatorColor = 0xFFFFFFFF; private int underlineColor = 0x1A000000; private boolean shouldExpand = false; private int scrollOffset = 52; private int indicatorHeight = 8; private int underlineHeight = 2; private int tabPadding = 24; private int indicatorPadding = 0; private int tabTextSize = 14; private int tabTextColor = 0xFF666666; private int tabDeactivateTextColor = 0xFF00CCCC; private final Typeface tabTypeface = null; private int lastScrollX = 0; private int tabBackgroundResId = R.drawable.selector_tab; private Locale locale; private boolean tabSwitch; public TabStrip(Context context, AttributeSet attrs) { this(context, attrs, 0); } public TabStrip(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); setFillViewport(true); setWillNotDraw(false); tabsContainer = new LinearLayout(context); tabsContainer.setOrientation(LinearLayout.HORIZONTAL); tabsContainer.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); addView(tabsContainer); DisplayMetrics dm = getResources().getDisplayMetrics(); scrollOffset = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, scrollOffset, dm); indicatorHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, indicatorHeight, dm); underlineHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, underlineHeight, dm); tabPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, tabPadding, dm); tabTextSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm); indicatorPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, indicatorPadding, dm); // get system attrs (android:textSize and android:textColor) TypedArray a = context.obtainStyledAttributes(attrs, ATTRS); tabTextSize = a.getDimensionPixelSize(0, tabTextSize); a.recycle(); a = context.obtainStyledAttributes(attrs, R.styleable.TabStrip); indicatorColor = a.getColor(R.styleable.TabStrip_TabStripIndicatorColor, indicatorColor); underlineColor = a.getColor(R.styleable.TabStrip_TabStripUnderlineColor, underlineColor); indicatorHeight = a.getDimensionPixelSize(R.styleable.TabStrip_TabStripIndicatorHeight, indicatorHeight); underlineHeight = a.getDimensionPixelSize(R.styleable.TabStrip_TabStripUnderlineHeight, underlineHeight); tabPadding = a.getDimensionPixelSize(R.styleable.TabStrip_TabStripTabPaddingLeftRight, tabPadding); tabBackgroundResId = a.getResourceId(R.styleable.TabStrip_TabStripTabBackground, tabBackgroundResId); shouldExpand = a.getBoolean(R.styleable.TabStrip_TabStripShouldExpand, shouldExpand); scrollOffset = a.getDimensionPixelSize(R.styleable.TabStrip_TabStripScrollOffset, scrollOffset); tabSwitch = a.getBoolean(R.styleable.TabStrip_TabStripTabSwitch, tabSwitch); tabTextColor = a.getColor(R.styleable.TabStrip_TabStripActivateTextColor, tabTextColor); tabDeactivateTextColor = a.getColor(R.styleable.TabStrip_TabStripDeactivateTextColor, tabDeactivateTextColor); indicatorPadding = a.getDimensionPixelSize(R.styleable.TabStrip_TabStripIndicatorPadding, indicatorPadding); a.recycle(); rectPaint = new Paint(); rectPaint.setAntiAlias(true); rectPaint.setStyle(Style.FILL); defaultTabLayoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT); expandedTabLayoutParams = new LinearLayout.LayoutParams(0, LayoutParams.MATCH_PARENT, 1.0f); if (locale == null) { locale = getResources().getConfiguration().locale; } } public void setViewPager(ViewPager pager) { this.pager = pager; if (pager.getAdapter() == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } pager.setOnPageChangeListener(pageListener); notifyDataSetChanged(); } @SuppressWarnings("UnusedDeclaration") public void setOnPageChangeListener(OnPageChangeListener listener) { this.delegatePageListener = listener; } private void notifyDataSetChanged() { tabsContainer.removeAllViews(); tabCount = pager.getAdapter().getCount(); for (int i = 0; i < tabCount; i++) { if (pager.getAdapter() instanceof IconTabProvider) { addIconTab(i, ((IconTabProvider) pager.getAdapter()).getPageIconResId(i)); } else { addTextTab(i, pager.getAdapter().getPageTitle(i).toString()); } } updateTabStyles(); getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() { @SuppressWarnings("deprecation") @SuppressLint("NewApi") @Override public void onGlobalLayout() { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) { getViewTreeObserver().removeGlobalOnLayoutListener(this); } else { getViewTreeObserver().removeOnGlobalLayoutListener(this); } currentPosition = pager.getCurrentItem(); scrollToChild(currentPosition, 0); } }); } private void addTextTab(final int position, String title) { TextView tab = new TextView(getContext()); tab.setText(title); tab.setGravity(Gravity.CENTER); tab.setSingleLine(); tab.setAllCaps(true); addTab(position, tab); } private void addIconTab(final int position, int resId) { ImageButton tab = new ImageButton(getContext()); tab.setImageResource(resId); addTab(position, tab); } private void addTab(final int position, View tab) { tab.setFocusable(true); tab.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { pager.setCurrentItem(position); } }); tab.setPadding(tabPadding, 0, tabPadding, 0); tabsContainer.addView(tab, position, shouldExpand ? expandedTabLayoutParams : defaultTabLayoutParams); } private void updateTabStyles() { for (int i = 0; i < tabCount; i++) { View v = tabsContainer.getChildAt(i); v.setBackgroundResource(tabBackgroundResId); if (v instanceof TextView) { TextView tab = (TextView) v; tab.setTextSize(TypedValue.COMPLEX_UNIT_PX, tabTextSize); int tabTypefaceStyle = Typeface.BOLD; tab.setTypeface(tabTypeface, tabTypefaceStyle); tab.setTextColor(i == currentPosition ? tabTextColor : tabDeactivateTextColor); } } } private void updateActivateTab(final int position) { for (int i = 0; i < tabCount; i++) { View v = tabsContainer.getChildAt(i); if (v instanceof TextView) { TextView tab = (TextView) v; tab.setTextColor(position == i ? tabTextColor : tabDeactivateTextColor); } else { v.setSelected(position == i); } } } private void scrollToChild(int position, int offset) { if (tabCount == 0) { return; } int newScrollX = tabsContainer.getChildAt(position).getLeft() + offset; if (position > 0 || offset > 0) { newScrollX -= scrollOffset; } if (newScrollX != lastScrollX) { lastScrollX = newScrollX; scrollTo(newScrollX, 0); } } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (isInEditMode() || tabCount == 0) { return; } final int height = getHeight(); // draw indicator line rectPaint.setColor(indicatorColor); // default: line below current tab View currentTab = tabsContainer.getChildAt(currentPosition); float lineLeft = currentTab.getLeft(); lineLeft += indicatorPadding; float lineRight = currentTab.getRight(); lineRight -= indicatorPadding; // if there is an offset, start interpolating left and right coordinates between current and next tab if (currentPositionOffset > 0f && currentPosition < tabCount - 1) { View nextTab = tabsContainer.getChildAt(currentPosition + 1); float nextTabLeft = nextTab.getLeft(); nextTabLeft += indicatorPadding; float nextTabRight = nextTab.getRight(); nextTabRight -= indicatorPadding; lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) * lineLeft); lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) * lineRight); } canvas.drawRect(lineLeft, height - indicatorHeight, lineRight, height - underlineHeight, rectPaint); // draw underline rectPaint.setColor(underlineColor); canvas.drawRect(0, height - underlineHeight, tabsContainer.getWidth(), height, rectPaint); } private class PageListener implements OnPageChangeListener { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { currentPosition = position; currentPositionOffset = positionOffset; scrollToChild(position, (int) (positionOffset * tabsContainer.getChildAt(position).getWidth())); invalidate(); if (delegatePageListener != null) { delegatePageListener.onPageScrolled(position, positionOffset, positionOffsetPixels); } } @Override public void onPageScrollStateChanged(int state) { if (state == ViewPager.SCROLL_STATE_IDLE) { scrollToChild(pager.getCurrentItem(), 0); } if (delegatePageListener != null) { delegatePageListener.onPageScrollStateChanged(state); } } @Override public void onPageSelected(int position) { updateActivateTab(position); if (delegatePageListener != null) { delegatePageListener.onPageSelected(position); } } } @Override public void onRestoreInstanceState(Parcelable state) { SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); currentPosition = savedState.currentPosition; requestLayout(); } @Override public Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState savedState = new SavedState(superState); savedState.currentPosition = currentPosition; return savedState; } static class SavedState extends BaseSavedState { int currentPosition; public SavedState(Parcelable superState) { super(superState); } private SavedState(Parcel in) { super(in); currentPosition = in.readInt(); } @Override public void writeToParcel(@NonNull Parcel dest, int flags) { super.writeToParcel(dest, flags); dest.writeInt(currentPosition); } public static final Creator<SavedState> CREATOR = new Creator<SavedState>() { @Override public SavedState createFromParcel(Parcel in) { return new SavedState(in); } @Override public SavedState[] newArray(int size) { return new SavedState[size]; } }; } }