Java tutorial
package com.lakshay.jimstimetable; /* * Copyright (C) 2013 Andreas Stuetz <andreas.stuetz@gmail.com> * * 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. */ import android.graphics.Typeface; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.ColorStateList; import android.content.res.TypedArray; import android.database.DataSetObserver; 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.v4.util.Pair; import android.support.v4.view.ViewCompat; 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.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewTreeObserver.OnGlobalLayoutListener; import android.widget.HorizontalScrollView; import android.widget.LinearLayout; import android.widget.TextView; import com.lakshay.jimstimetable.R; import java.util.Locale; public class PagerSlidingTabStrip extends HorizontalScrollView { private static final float OPAQUE = 1.0f; private static final float HALF_TRANSP = 0.5f; public interface CustomTabProvider { public View getCustomTabView(ViewGroup parent, int position); } public interface OnTabReselectedListener { public void onTabReselected(int position); } // @formatter:off private static final int[] ATTRS = new int[] { android.R.attr.textColorPrimary, android.R.attr.textSize, android.R.attr.textColor, android.R.attr.paddingLeft, android.R.attr.paddingRight, }; // @formatter:on private final PagerAdapterObserver adapterObserver = new PagerAdapterObserver(); //These indexes must be related with the ATTR array above private static final int TEXT_COLOR_PRIMARY = 0; private static final int TEXT_SIZE_INDEX = 1; private static final int TEXT_COLOR_INDEX = 2; private static final int PADDING_LEFT_INDEX = 3; private static final int PADDING_RIGHT_INDEX = 4; private LinearLayout.LayoutParams defaultTabLayoutParams; private LinearLayout.LayoutParams expandedTabLayoutParams; private final PageListener pageListener = new PageListener(); private OnTabReselectedListener tabReselectedListener = null; public OnPageChangeListener delegatePageListener; private LinearLayout tabsContainer; private ViewPager pager; private int tabCount; private int currentPosition = 0; private float currentPositionOffset = 0f; private Paint rectPaint; private Paint dividerPaint; private int indicatorColor; private int indicatorHeight = 2; private int underlineHeight = 0; private int underlineColor; private int dividerWidth = 0; private int dividerPadding = 0; private int dividerColor; private int tabPadding = 12; private int tabTextSize = 14; private ColorStateList tabTextColor = null; private float tabTextAlpha = HALF_TRANSP; private float tabTextSelectedAlpha = OPAQUE; private int padding = 0; private boolean shouldExpand = false; private boolean textAllCaps = true; private boolean isPaddingMiddle = false; private Typeface tabTypeface = null; private int tabTypefaceStyle = Typeface.BOLD; private int tabTypefaceSelectedStyle = Typeface.BOLD; private int scrollOffset; private int lastScrollX = 0; private int tabBackgroundResId = R.drawable.background_tab; private Locale locale; public PagerSlidingTabStrip(Context context) { this(context, null); } public PagerSlidingTabStrip(Context context, AttributeSet attrs) { this(context, attrs, 0); } public PagerSlidingTabStrip(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); dividerPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dividerPadding, dm); tabPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, tabPadding, dm); dividerWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dividerWidth, dm); tabTextSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm); // get system attrs (android:textSize and android:textColor) TypedArray a = context.obtainStyledAttributes(attrs, ATTRS); tabTextSize = a.getDimensionPixelSize(TEXT_SIZE_INDEX, tabTextSize); ColorStateList colorStateList = a.getColorStateList(TEXT_COLOR_INDEX); int textPrimaryColor = a.getColor(TEXT_COLOR_PRIMARY, android.R.color.white); if (colorStateList != null) { tabTextColor = colorStateList; } else { tabTextColor = getColorStateList(textPrimaryColor); } underlineColor = textPrimaryColor; dividerColor = textPrimaryColor; indicatorColor = textPrimaryColor; int paddingLeft = a.getDimensionPixelSize(PADDING_LEFT_INDEX, padding); int paddingRight = a.getDimensionPixelSize(PADDING_RIGHT_INDEX, padding); a.recycle(); //In case we have the padding they must be equal so we take the biggest padding = Math.max(paddingLeft, paddingRight); // get custom attrs a = context.obtainStyledAttributes(attrs, R.styleable.PagerSlidingTabStrip); indicatorColor = a.getColor(R.styleable.PagerSlidingTabStrip_pstsIndicatorColor, indicatorColor); underlineColor = a.getColor(R.styleable.PagerSlidingTabStrip_pstsUnderlineColor, underlineColor); dividerColor = a.getColor(R.styleable.PagerSlidingTabStrip_pstsDividerColor, dividerColor); dividerWidth = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsDividerWidth, dividerWidth); indicatorHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsIndicatorHeight, indicatorHeight); underlineHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsUnderlineHeight, underlineHeight); dividerPadding = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsDividerPadding, dividerPadding); tabPadding = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsTabPaddingLeftRight, tabPadding); tabBackgroundResId = a.getResourceId(R.styleable.PagerSlidingTabStrip_pstsTabBackground, tabBackgroundResId); shouldExpand = a.getBoolean(R.styleable.PagerSlidingTabStrip_pstsShouldExpand, shouldExpand); scrollOffset = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsScrollOffset, scrollOffset); textAllCaps = a.getBoolean(R.styleable.PagerSlidingTabStrip_pstsTextAllCaps, textAllCaps); isPaddingMiddle = a.getBoolean(R.styleable.PagerSlidingTabStrip_pstsPaddingMiddle, isPaddingMiddle); tabTypefaceStyle = a.getInt(R.styleable.PagerSlidingTabStrip_pstsTextStyle, Typeface.BOLD); tabTypefaceSelectedStyle = a.getInt(R.styleable.PagerSlidingTabStrip_pstsTextSelectedStyle, Typeface.BOLD); tabTextAlpha = a.getFloat(R.styleable.PagerSlidingTabStrip_pstsTextAlpha, HALF_TRANSP); tabTextSelectedAlpha = a.getFloat(R.styleable.PagerSlidingTabStrip_pstsTextSelectedAlpha, OPAQUE); a.recycle(); setMarginBottomTabContainer(); rectPaint = new Paint(); rectPaint.setAntiAlias(true); rectPaint.setStyle(Style.FILL); dividerPaint = new Paint(); dividerPaint.setAntiAlias(true); dividerPaint.setStrokeWidth(dividerWidth); 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; } } private void setMarginBottomTabContainer() { ViewGroup.MarginLayoutParams mlp = (MarginLayoutParams) tabsContainer.getLayoutParams(); int bottomMargin = indicatorHeight >= underlineHeight ? indicatorHeight : underlineHeight; mlp.setMargins(mlp.leftMargin, mlp.topMargin, mlp.rightMargin, bottomMargin); tabsContainer.setLayoutParams(mlp); } public void setViewPager(ViewPager pager) { this.pager = pager; if (pager.getAdapter() == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } pager.setOnPageChangeListener(pageListener); pager.getAdapter().registerDataSetObserver(adapterObserver); adapterObserver.setAttached(true); notifyDataSetChanged(); } public void notifyDataSetChanged() { tabsContainer.removeAllViews(); tabCount = pager.getAdapter().getCount(); View tabView; for (int i = 0; i < tabCount; i++) { if (pager.getAdapter() instanceof CustomTabProvider) { tabView = ((CustomTabProvider) pager.getAdapter()).getCustomTabView(this, i); } else { tabView = LayoutInflater.from(getContext()).inflate(R.layout.tab, this, false); } CharSequence title = pager.getAdapter().getPageTitle(i); addTab(i, title, tabView); } 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(); currentPositionOffset = 0f; scrollToChild(currentPosition, 0); updateSelection(currentPosition); } }); } private void addTab(final int position, CharSequence title, View tabView) { TextView textView = (TextView) tabView.findViewById(R.id.tab_title); if (textView != null) { if (title != null) textView.setText(title); float alpha = pager.getCurrentItem() == position ? tabTextSelectedAlpha : tabTextAlpha; ViewCompat.setAlpha(textView, alpha); } tabView.setFocusable(true); tabView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if (pager.getCurrentItem() != position) { View tab = tabsContainer.getChildAt(pager.getCurrentItem()); notSelected(tab); pager.setCurrentItem(position); } else if (tabReselectedListener != null) { tabReselectedListener.onTabReselected(position); } } }); tabsContainer.addView(tabView, position, shouldExpand ? expandedTabLayoutParams : defaultTabLayoutParams); } private void updateTabStyles() { for (int i = 0; i < tabCount; i++) { View v = tabsContainer.getChildAt(i); v.setBackgroundResource(tabBackgroundResId); v.setPadding(tabPadding, v.getPaddingTop(), tabPadding, v.getPaddingBottom()); TextView tab_title = (TextView) v.findViewById(R.id.tab_title); if (tab_title != null) { tab_title.setTextSize(TypedValue.COMPLEX_UNIT_PX, tabTextSize); tab_title.setTypeface(tabTypeface, pager.getCurrentItem() == i ? tabTypefaceSelectedStyle : tabTypefaceStyle); if (tabTextColor != null) { tab_title.setTextColor(tabTextColor); } // setAllCaps() is only available from API 14, so the upper case is made manually if we are on a // pre-ICS-build if (textAllCaps) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { tab_title.setAllCaps(true); } else { tab_title.setText(tab_title.getText().toString().toUpperCase(locale)); } } } } } private void scrollToChild(int position, int offset) { if (tabCount == 0) { return; } int newScrollX = tabsContainer.getChildAt(position).getLeft() + offset; if (position > 0 || offset > 0) { //Half screen offset. //- Either tabs start at the middle of the view scrolling straight away //- Or tabs start at the begging (no padding) scrolling when indicator gets // to the middle of the view width newScrollX -= scrollOffset; Pair<Float, Float> lines = getIndicatorCoordinates(); newScrollX += ((lines.second - lines.first) / 2); } if (newScrollX != lastScrollX) { lastScrollX = newScrollX; scrollTo(newScrollX, 0); } } private Pair<Float, Float> getIndicatorCoordinates() { // default: line below current tab View currentTab = tabsContainer.getChildAt(currentPosition); float lineLeft = currentTab.getLeft(); float lineRight = currentTab.getRight(); // 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); final float nextTabLeft = nextTab.getLeft(); final float nextTabRight = nextTab.getRight(); lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) * lineLeft); lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) * lineRight); } return new Pair<Float, Float>(lineLeft, lineRight); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { if (isPaddingMiddle || padding > 0) { //Make sure tabContainer is bigger than the HorizontalScrollView to be able to scroll tabsContainer.setMinimumWidth(getWidth()); //Clipping padding to false to see the tabs while we pass them swiping setClipToPadding(false); } if (tabsContainer.getChildCount() > 0) { tabsContainer.getChildAt(0).getViewTreeObserver() .addOnGlobalLayoutListener(firstTabGlobalLayoutListener); } super.onLayout(changed, l, t, r, b); } private OnGlobalLayoutListener firstTabGlobalLayoutListener = new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { View view = tabsContainer.getChildAt(0); if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) { getViewTreeObserver().removeGlobalOnLayoutListener(this); } else { getViewTreeObserver().removeOnGlobalLayoutListener(this); } if (isPaddingMiddle) { int mHalfWidthFirstTab = view.getWidth() / 2; padding = getWidth() / 2 - mHalfWidthFirstTab; } setPadding(padding, getPaddingTop(), padding, getPaddingBottom()); if (scrollOffset == 0) scrollOffset = getWidth() / 2 - padding; } }; @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (isInEditMode() || tabCount == 0) { return; } final int height = getHeight(); // draw indicator line rectPaint.setColor(indicatorColor); Pair<Float, Float> lines = getIndicatorCoordinates(); canvas.drawRect(lines.first + padding, height - indicatorHeight, lines.second + padding, height, rectPaint); // draw underline rectPaint.setColor(underlineColor); canvas.drawRect(padding, height - underlineHeight, tabsContainer.getWidth() + padding, height, rectPaint); // draw divider if (dividerWidth != 0) { dividerPaint.setStrokeWidth(dividerWidth); dividerPaint.setColor(dividerColor); for (int i = 0; i < tabCount - 1; i++) { View tab = tabsContainer.getChildAt(i); canvas.drawLine(tab.getRight(), dividerPadding, tab.getRight(), height - dividerPadding, dividerPaint); } } } public void setOnTabReselectedListener(OnTabReselectedListener tabReselectedListener) { this.tabReselectedListener = tabReselectedListener; } public void setOnPageChangeListener(OnPageChangeListener listener) { this.delegatePageListener = listener; } private class PageListener implements OnPageChangeListener { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { currentPosition = position; currentPositionOffset = positionOffset; int offset = tabCount > 0 ? (int) (positionOffset * tabsContainer.getChildAt(position).getWidth()) : 0; scrollToChild(position, offset); 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); } //Full alpha for current item View currentTab = tabsContainer.getChildAt(pager.getCurrentItem()); selected(currentTab); //Half transparent for prev item if (pager.getCurrentItem() - 1 >= 0) { View prevTab = tabsContainer.getChildAt(pager.getCurrentItem() - 1); notSelected(prevTab); } //Half transparent for next item if (pager.getCurrentItem() + 1 <= pager.getAdapter().getCount() - 1) { View nextTab = tabsContainer.getChildAt(pager.getCurrentItem() + 1); notSelected(nextTab); } if (delegatePageListener != null) { delegatePageListener.onPageScrollStateChanged(state); } } @Override public void onPageSelected(int position) { updateSelection(position); if (delegatePageListener != null) { delegatePageListener.onPageSelected(position); } } } private void updateSelection(int position) { for (int i = 0; i < tabCount; ++i) { View tv = tabsContainer.getChildAt(i); final boolean selected = i == position; tv.setSelected(selected); if (selected) { selected(tv); } else { notSelected(tv); } } } private void notSelected(View tab) { if (tab != null) { TextView title = (TextView) tab.findViewById(R.id.tab_title); if (title != null) { title.setTypeface(tabTypeface, tabTypefaceStyle); ViewCompat.setAlpha(title, tabTextAlpha); } } } private void selected(View tab) { if (tab != null) { TextView title = (TextView) tab.findViewById(R.id.tab_title); if (title != null) { title.setTypeface(tabTypeface, tabTypefaceSelectedStyle); ViewCompat.setAlpha(title, tabTextSelectedAlpha); } } } private class PagerAdapterObserver extends DataSetObserver { private boolean attached = false; @Override public void onChanged() { notifyDataSetChanged(); } public void setAttached(boolean attached) { this.attached = attached; } public boolean isAttached() { return attached; } } @Override protected void onAttachedToWindow() { super.onAttachedToWindow(); if (pager != null) { if (!adapterObserver.isAttached()) { pager.getAdapter().registerDataSetObserver(adapterObserver); adapterObserver.setAttached(true); } } } @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); if (pager != null) { if (adapterObserver.isAttached()) { pager.getAdapter().unregisterDataSetObserver(adapterObserver); adapterObserver.setAttached(false); } } } @Override public void onRestoreInstanceState(Parcelable state) { SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); currentPosition = savedState.currentPosition; if (currentPosition != 0 && tabsContainer.getChildCount() > 0) { notSelected(tabsContainer.getChildAt(0)); selected(tabsContainer.getChildAt(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(Parcel dest, int flags) { super.writeToParcel(dest, flags); dest.writeInt(currentPosition); } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { @Override public SavedState createFromParcel(Parcel in) { return new SavedState(in); } @Override public SavedState[] newArray(int size) { return new SavedState[size]; } }; } public int getIndicatorColor() { return this.indicatorColor; } public int getIndicatorHeight() { return indicatorHeight; } public int getUnderlineColor() { return underlineColor; } public int getDividerColor() { return dividerColor; } public int getDividerWidth() { return dividerWidth; } public int getUnderlineHeight() { return underlineHeight; } public int getDividerPadding() { return dividerPadding; } public int getScrollOffset() { return scrollOffset; } public boolean getShouldExpand() { return shouldExpand; } public int getTextSize() { return tabTextSize; } public boolean isTextAllCaps() { return textAllCaps; } public ColorStateList getTextColor() { return tabTextColor; } public int getTabBackground() { return tabBackgroundResId; } public int getTabPaddingLeftRight() { return tabPadding; } public void setIndicatorColor(int indicatorColor) { this.indicatorColor = indicatorColor; invalidate(); } public void setIndicatorColorResource(int resId) { this.indicatorColor = getResources().getColor(resId); invalidate(); } public void setIndicatorHeight(int indicatorLineHeightPx) { this.indicatorHeight = indicatorLineHeightPx; invalidate(); } public void setUnderlineColor(int underlineColor) { this.underlineColor = underlineColor; invalidate(); } public void setUnderlineColorResource(int resId) { this.underlineColor = getResources().getColor(resId); invalidate(); } public void setDividerColor(int dividerColor) { this.dividerColor = dividerColor; invalidate(); } public void setDividerColorResource(int resId) { this.dividerColor = getResources().getColor(resId); invalidate(); } public void setDividerWidth(int dividerWidthPx) { this.dividerWidth = dividerWidthPx; invalidate(); } public void setUnderlineHeight(int underlineHeightPx) { this.underlineHeight = underlineHeightPx; invalidate(); } public void setDividerPadding(int dividerPaddingPx) { this.dividerPadding = dividerPaddingPx; invalidate(); } public void setScrollOffset(int scrollOffsetPx) { this.scrollOffset = scrollOffsetPx; invalidate(); } public void setShouldExpand(boolean shouldExpand) { this.shouldExpand = shouldExpand; if (pager != null) { requestLayout(); } } public void setAllCaps(boolean textAllCaps) { this.textAllCaps = textAllCaps; } public void setTextSize(int textSizePx) { this.tabTextSize = textSizePx; updateTabStyles(); } public void setTextColor(int textColor) { setTextColor(getColorStateList(textColor)); } private ColorStateList getColorStateList(int textColor) { return new ColorStateList(new int[][] { new int[] {} }, new int[] { textColor }); } public void setTextColor(ColorStateList colorStateList) { this.tabTextColor = colorStateList; updateTabStyles(); } public void setTextColorResource(int resId) { setTextColor(getResources().getColor(resId)); } public void setTextColorStateListResource(int resId) { setTextColor(getResources().getColorStateList(resId)); } public void setTypeface(Typeface typeface, int style) { this.tabTypeface = typeface; this.tabTypefaceSelectedStyle = style; updateTabStyles(); } public void setTabBackground(int resId) { this.tabBackgroundResId = resId; } public void setTabPaddingLeftRight(int paddingPx) { this.tabPadding = paddingPx; updateTabStyles(); } }