Java tutorial
/* * Copyright (C) 2011 Patrik Akerfeldt * Copyright (C) 2011 Francisco Figueiredo Jr. * Copyright (C) 2011 Jake Wharton * * 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.fanfou.app.opensource.ui.viewpager; import java.util.ArrayList; import android.content.Context; import android.content.res.Resources; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Path; import android.graphics.RectF; import android.os.Parcel; import android.os.Parcelable; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import com.fanfou.app.opensource.HomePage; import com.fanfou.app.opensource.R; /** * A TitlePageIndicator is a PageIndicator which displays the title of left view * (if exist), the title of the current select view (centered) and the title of * the right view (if exist). When the user scrolls the ViewPager then titles * are also scrolled. */ /** * @author mcxiaoke * @version 1.1 2011.08.20 * @version 1.2 2011.11.04 * @version 1.3 2011.11.08 * @version 1.4 2011.11.11 * */ public class TitlePageIndicator extends View implements PageIndicator { public enum IndicatorStyle { None(0), Triangle(1), Underline(2); public static IndicatorStyle fromValue(final int value) { for (final IndicatorStyle style : IndicatorStyle.values()) { if (style.value == value) { return style; } } return null; } public final int value; private IndicatorStyle(final int value) { this.value = value; } } static class SavedState extends BaseSavedState { int currentPage; public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { @Override public SavedState createFromParcel(final Parcel in) { return new SavedState(in); } @Override public SavedState[] newArray(final int size) { return new SavedState[size]; } }; private SavedState(final Parcel in) { super(in); this.currentPage = in.readInt(); } public SavedState(final Parcelable superState) { super(superState); } @Override public void writeToParcel(final Parcel dest, final int flags) { super.writeToParcel(dest, flags); dest.writeInt(this.currentPage); } } private static final String TAG = TitlePageIndicator.class.getSimpleName(); /** * Percentage indicating what percentage of the screen width away from * center should the underline be fully faded. A value of 0.25 means that * halfway between the center of the screen and an edge. */ private static final float SELECTION_FADE_PERCENTAGE = 0.25f; /** * Percentage indicating what percentage of the screen width away from * center should the selected text bold turn off. A value of 0.05 means that * 10% between the center and an edge. */ private static final float BOLD_FADE_PERCENTAGE = 0.05f; private ViewPager mViewPager; private TitleProvider mTitleProvider; private int mCurrentPage; private int mCurrentOffset; private final Paint mPaintText; private boolean mBoldText; private int mColorText; private int mColorSelected; private final Path mPath; private final Paint mPaintFooterLine; private IndicatorStyle mFooterIndicatorStyle; private final Paint mPaintFooterIndicator; private float mFooterIndicatorHeight; private final float mFooterIndicatorUnderlinePadding; private float mFooterPadding; private float mTitlePadding; /** Left and right side padding for not active view titles. */ private float mClipPadding; private float mFooterLineHeight; public TitlePageIndicator(final Context context) { this(context, null); } public TitlePageIndicator(final Context context, final AttributeSet attrs) { this(context, attrs, R.attr.titlePageIndicatorStyle); } public TitlePageIndicator(final Context context, final AttributeSet attrs, final int defStyle) { super(context, attrs, defStyle); // Load defaults from resources final Resources res = getResources(); final int defaultFooterColor = res.getColor(R.color.default_title_indicator_footer_color); final float defaultFooterLineHeight = res.getDimension(R.dimen.default_title_indicator_footer_line_height); final int defaultFooterIndicatorStyle = res .getInteger(R.integer.default_title_indicator_footer_indicator_style); final float defaultFooterIndicatorHeight = res .getDimension(R.dimen.default_title_indicator_footer_indicator_height); final float defaultFooterIndicatorUnderlinePadding = res .getDimension(R.dimen.default_title_indicator_footer_indicator_underline_padding); final float defaultFooterPadding = res.getDimension(R.dimen.default_title_indicator_footer_padding); final int defaultSelectedColor = res.getColor(R.color.default_title_indicator_selected_color); final boolean defaultSelectedBold = res.getBoolean(R.bool.default_title_indicator_selected_bold); final int defaultTextColor = res.getColor(R.color.default_title_indicator_text_color); final float defaultTextSize = res.getDimension(R.dimen.default_title_indicator_text_size); final float defaultTitlePadding = res.getDimension(R.dimen.default_title_indicator_title_padding); final float defaultClipPadding = res.getDimension(R.dimen.default_title_indicator_clip_padding); // Retrieve styles attributes final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TitlePageIndicator, defStyle, R.style.Widget_TitlePageIndicator); // Retrieve the colors to be used for this view and apply them. this.mFooterLineHeight = a.getDimension(R.styleable.TitlePageIndicator_footerLineHeight, defaultFooterLineHeight); this.mFooterIndicatorStyle = IndicatorStyle.fromValue( a.getInteger(R.styleable.TitlePageIndicator_footerIndicatorStyle, defaultFooterIndicatorStyle)); this.mFooterIndicatorHeight = a.getDimension(R.styleable.TitlePageIndicator_footerIndicatorHeight, defaultFooterIndicatorHeight); this.mFooterIndicatorUnderlinePadding = a.getDimension( R.styleable.TitlePageIndicator_footerIndicatorUnderlinePadding, defaultFooterIndicatorUnderlinePadding); this.mFooterPadding = a.getDimension(R.styleable.TitlePageIndicator_footerPadding, defaultFooterPadding); this.mTitlePadding = a.getDimension(R.styleable.TitlePageIndicator_titlePadding, defaultTitlePadding); this.mClipPadding = a.getDimension(R.styleable.TitlePageIndicator_clipPadding, defaultClipPadding); this.mColorSelected = a.getColor(R.styleable.TitlePageIndicator_selectedColor, defaultSelectedColor); this.mColorText = a.getColor(R.styleable.TitlePageIndicator_textColor, defaultTextColor); this.mBoldText = a.getBoolean(R.styleable.TitlePageIndicator_selectedBold, defaultSelectedBold); final float textSize = a.getDimension(R.styleable.TitlePageIndicator_textSize, defaultTextSize); final int footerColor = a.getColor(R.styleable.TitlePageIndicator_footerColor, defaultFooterColor); this.mPaintText = new Paint(); this.mPaintText.setTextSize(textSize); this.mPaintText.setAntiAlias(true); this.mPaintFooterLine = new Paint(); this.mPaintFooterLine.setStyle(Paint.Style.FILL_AND_STROKE); this.mPaintFooterLine.setStrokeWidth(this.mFooterLineHeight); this.mPaintFooterLine.setColor(footerColor); this.mPaintFooterIndicator = new Paint(); this.mPaintFooterIndicator.setStyle(Paint.Style.FILL_AND_STROKE); this.mPaintFooterIndicator.setColor(footerColor); a.recycle(); this.mPath = new Path(); } /** * Calculate the bounds for a view's title * * @param index * @param paint * @return */ private RectF calcBounds(final int index, final Paint paint) { // Calculate the text bounds final RectF bounds = new RectF(); bounds.right = paint.measureText(this.mTitleProvider.getTitle(index)); bounds.bottom = paint.descent() - paint.ascent(); return bounds; } /** * Calculate views bounds and scroll them according to the current index * * @param paint * @param currentIndex * @return */ private ArrayList<RectF> calculateAllBounds(final Paint paint) { final ArrayList<RectF> list = new ArrayList<RectF>(); // For each views (If no values then add a fake one) final int count = getPageCount(); final int width = getWidth(); final int halfWidth = width / 2; for (int i = 0; i < count; i++) { final RectF bounds = calcBounds(i, paint); final float w = (bounds.right - bounds.left); final float h = (bounds.bottom - bounds.top); bounds.left = ((halfWidth) - (w / 2) - this.mCurrentOffset) + ((i - this.mCurrentPage) * width); bounds.right = bounds.left + w; bounds.top = 0; bounds.bottom = h; list.add(bounds); } return list; } /** * Set bounds for the left textView including clip padding. * * @param curViewBound * current bounds. * @param curViewWidth * width of the view. */ private void clipViewOnTheLeft(final RectF curViewBound, final float curViewWidth, final int left) { curViewBound.left = left + this.mClipPadding; curViewBound.right = this.mClipPadding + curViewWidth; } /** * Set bounds for the right textView including clip padding. * * @param curViewBound * current bounds. * @param curViewWidth * width of the view. */ private void clipViewOnTheRight(final RectF curViewBound, final float curViewWidth, final int right) { curViewBound.right = right - this.mClipPadding; curViewBound.left = curViewBound.right - curViewWidth; } public float getClipPadding() { return this.mClipPadding; } public int getFooterColor() { return this.mPaintFooterLine.getColor(); } public float getFooterIndicatorHeight() { return this.mFooterIndicatorHeight; } public float getFooterIndicatorPadding() { return this.mFooterPadding; } public IndicatorStyle getFooterIndicatorStyle() { return this.mFooterIndicatorStyle; } public float getFooterLineHeight() { return this.mFooterLineHeight; } @Override public int getPageCount() { return HomePage.NUMS_OF_PAGE; } @Override public int getPageWidth() { return this.mViewPager.getWidth(); } public int getSelectedColor() { return this.mColorSelected; } public int getTextColor() { return this.mColorText; } public float getTextSize() { return this.mPaintText.getTextSize(); } public float getTitlePadding() { return this.mTitlePadding; } public boolean isSelectedBold() { return this.mBoldText; } /** * Determines the height of this view * * @param measureSpec * A measureSpec packed into an int * @return The height of the view, honoring constraints from measureSpec */ private int measureHeight(final int measureSpec) { float result = 0; final int specMode = MeasureSpec.getMode(measureSpec); final int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.EXACTLY) { // We were told how big to be result = specSize; } else { // Calculate the text bounds final RectF bounds = new RectF(); bounds.bottom = this.mPaintText.descent() - this.mPaintText.ascent(); result = (bounds.bottom - bounds.top) + this.mFooterLineHeight + this.mFooterPadding; if (this.mFooterIndicatorStyle != IndicatorStyle.None) { result += this.mFooterIndicatorHeight; } } return (int) result; } /** * Determines the width of this view * * @param measureSpec * A measureSpec packed into an int * @return The width of the view, honoring constraints from measureSpec */ private int measureWidth(final int measureSpec) { int result = 0; final int specMode = MeasureSpec.getMode(measureSpec); final int specSize = MeasureSpec.getSize(measureSpec); if (specMode != MeasureSpec.EXACTLY) { throw new IllegalStateException(getClass().getSimpleName() + " can only be used in EXACTLY mode."); } result = specSize; return result; } /* * (non-Javadoc) * * @see android.view.View#onDraw(android.graphics.Canvas) */ @Override protected void onDraw(final Canvas canvas) { super.onDraw(canvas); // Calculate views bounds final ArrayList<RectF> bounds = calculateAllBounds(this.mPaintText); final int count = getPageCount(); final int countMinusOne = count - 1; final float halfWidth = getWidth() / 2f; final int left = getLeft(); final float leftClip = left + this.mClipPadding; final int width = getWidth(); final int height = getHeight(); final int right = left + width; final float rightClip = right - this.mClipPadding; final float offsetPercent = (1.0f * this.mCurrentOffset) / width; int page = this.mCurrentPage; if (this.mCurrentOffset > halfWidth) { page++; } final boolean currentSelected = (offsetPercent <= TitlePageIndicator.SELECTION_FADE_PERCENTAGE); final boolean currentBold = (offsetPercent <= TitlePageIndicator.BOLD_FADE_PERCENTAGE); final float selectedPercent = (TitlePageIndicator.SELECTION_FADE_PERCENTAGE - offsetPercent) / TitlePageIndicator.SELECTION_FADE_PERCENTAGE; // Verify if the current view must be clipped to the screen final RectF curPageBound = bounds.get(this.mCurrentPage); // fix null pointer exception if (curPageBound != null) { final float curPageWidth = curPageBound.right - curPageBound.left; if (curPageBound.left < leftClip) { // Try to clip to the screen (left side) clipViewOnTheLeft(curPageBound, curPageWidth, left); } if (curPageBound.right > rightClip) { // Try to clip to the screen (right side) clipViewOnTheRight(curPageBound, curPageWidth, right); } } // Left views starting from the current position if (this.mCurrentPage > 0) { for (int i = this.mCurrentPage - 1; i >= 0; i--) { final RectF bound = bounds.get(i); // Is left side is outside the screen if (bound.left < leftClip) { final float w = bound.right - bound.left; // Try to clip to the screen (left side) clipViewOnTheLeft(bound, w, left); // Except if there's an intersection with the right view final RectF rightBound = bounds.get(i + 1); // Intersection if ((bound.right + this.mTitlePadding) > rightBound.left) { bound.left = rightBound.left - w - this.mTitlePadding; bound.right = bound.left + w; } } } } // Right views starting from the current position if (this.mCurrentPage < countMinusOne) { for (int i = this.mCurrentPage + 1; i < count; i++) { final RectF bound = bounds.get(i); // If right side is outside the screen if (bound.right > rightClip) { final float w = bound.right - bound.left; // Try to clip to the screen (right side) clipViewOnTheRight(bound, w, right); // Except if there's an intersection with the left view final RectF leftBound = bounds.get(i - 1); // Intersection if ((bound.left - this.mTitlePadding) < leftBound.right) { bound.left = leftBound.right + this.mTitlePadding; bound.right = bound.left + w; } } } } // if(App.DEBUG){ // Log.e(TAG, // "==============================================================="); // Log.e(TAG, "onDraw() mCurrentPage="+mCurrentPage); // Log.e(TAG, "onDraw() "); // Log.e(TAG, "onDraw() "); // Log.e(TAG, "onDraw() "); // Log.e(TAG, "onDraw() "); // Log.e(TAG, "onDraw() "); // Log.e(TAG, // "==============================================================="); // } // Now draw views for (int i = 0; i < count; i++) { // Get the title final RectF bound = bounds.get(i); // Only if one side is visible if (((bound.left > left) && (bound.left < right)) || ((bound.right > left) && (bound.right < right))) { final boolean currentPage = (i == page); // Only set bold if we are within bounds this.mPaintText.setFakeBoldText(currentPage && currentBold && this.mBoldText); // Draw text as unselected this.mPaintText.setColor(this.mColorText); canvas.drawText(this.mTitleProvider.getTitle(i), bound.left, bound.bottom, this.mPaintText); // If we are within the selected bounds draw the selected text if (currentPage && currentSelected) { this.mPaintText.setColor(this.mColorSelected); this.mPaintText.setAlpha((int) ((this.mColorSelected >>> 24) * selectedPercent)); canvas.drawText(this.mTitleProvider.getTitle(i), bound.left, bound.bottom, this.mPaintText); } } } // Draw the footer line // mPath = new Path(); this.mPath.reset(); this.mPath.moveTo(0, height - this.mFooterLineHeight); this.mPath.lineTo(width, height - this.mFooterLineHeight); this.mPath.close(); canvas.drawPath(this.mPath, this.mPaintFooterLine); switch (this.mFooterIndicatorStyle) { case Triangle: this.mPath.moveTo(halfWidth, height - this.mFooterLineHeight - this.mFooterIndicatorHeight); this.mPath.lineTo(halfWidth + this.mFooterIndicatorHeight, height - this.mFooterLineHeight); this.mPath.lineTo(halfWidth - this.mFooterIndicatorHeight, height - this.mFooterLineHeight); this.mPath.close(); canvas.drawPath(this.mPath, this.mPaintFooterIndicator); break; case Underline: if (!currentSelected) { break; } final RectF underlineBounds = bounds.get(page); this.mPath.moveTo(underlineBounds.left - this.mFooterIndicatorUnderlinePadding, height - this.mFooterLineHeight); this.mPath.lineTo(underlineBounds.right + this.mFooterIndicatorUnderlinePadding, height - this.mFooterLineHeight); this.mPath.lineTo(underlineBounds.right + this.mFooterIndicatorUnderlinePadding, height - this.mFooterLineHeight - this.mFooterIndicatorHeight); this.mPath.lineTo(underlineBounds.left - this.mFooterIndicatorUnderlinePadding, height - this.mFooterLineHeight - this.mFooterIndicatorHeight); this.mPath.close(); this.mPaintFooterIndicator.setAlpha((int) (0xFF * selectedPercent)); canvas.drawPath(this.mPath, this.mPaintFooterIndicator); this.mPaintFooterIndicator.setAlpha(0xFF); break; } } /* * (non-Javadoc) * * @see android.view.View#onMeasure(int, int) */ @Override protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) { setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec)); } @Override public void onPageScrolled(final int position, final float positionOffset, final int positionOffsetPixels) { this.mCurrentPage = position % HomePage.NUMS_OF_PAGE; this.mCurrentOffset = positionOffsetPixels; invalidate(); } @Override public void onPageSelected(final int position) { this.mCurrentPage = position % HomePage.NUMS_OF_PAGE; invalidate(); } @Override public void onRestoreInstanceState(final Parcelable state) { final SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); this.mCurrentPage = savedState.currentPage; requestLayout(); } @Override public Parcelable onSaveInstanceState() { final Parcelable superState = super.onSaveInstanceState(); final SavedState savedState = new SavedState(superState); savedState.currentPage = this.mCurrentPage; return savedState; } // @Override public boolean onTouchEvent2(final MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN) { final int count = getPageCount(); final int width = getWidth(); final float halfWidth = width / 2f; final float sixthWidth = width / 6f; if ((this.mCurrentPage > 0) && (event.getX() < (halfWidth - sixthWidth))) { this.mViewPager.setCurrentItem(this.mCurrentPage - 1); return true; } else if ((this.mCurrentPage < (count - 1)) && (event.getX() > (halfWidth + sixthWidth))) { this.mViewPager.setCurrentItem(this.mCurrentPage + 1); return true; } } return super.onTouchEvent(event); } public void setClipPadding(final float clipPadding) { this.mClipPadding = clipPadding; invalidate(); } @Override public void setCurrentItem(final int item) { if (this.mViewPager == null) { throw new IllegalStateException("ViewPager has not been bound."); } this.mCurrentPage = item; invalidate(); } public void setFooterColor(final int footerColor) { this.mPaintFooterLine.setColor(footerColor); this.mPaintFooterIndicator.setColor(footerColor); invalidate(); } public void setFooterIndicatorHeight(final float footerTriangleHeight) { this.mFooterIndicatorHeight = footerTriangleHeight; invalidate(); } public void setFooterIndicatorPadding(final float footerIndicatorPadding) { this.mFooterPadding = footerIndicatorPadding; invalidate(); } public void setFooterIndicatorStyle(final IndicatorStyle indicatorStyle) { this.mFooterIndicatorStyle = indicatorStyle; invalidate(); } public void setFooterLineHeight(final float footerLineHeight) { this.mFooterLineHeight = footerLineHeight; this.mPaintFooterLine.setStrokeWidth(this.mFooterLineHeight); invalidate(); } public void setSelectedBold(final boolean selectedBold) { this.mBoldText = selectedBold; invalidate(); } public void setSelectedColor(final int selectedColor) { this.mColorSelected = selectedColor; invalidate(); } public void setTextColor(final int textColor) { this.mPaintText.setColor(textColor); this.mColorText = textColor; invalidate(); } public void setTextSize(final float textSize) { this.mPaintText.setTextSize(textSize); invalidate(); } public void setTitlePadding(final float titlePadding) { this.mTitlePadding = titlePadding; invalidate(); } public void setTitleProvider(final TitleProvider provider) { this.mTitleProvider = provider; } @Override public void setViewPager(final ViewPager view) { if (view.getAdapter() == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } this.mViewPager = view; invalidate(); } @Override public void setViewPager(final ViewPager view, final int initialPosition) { setViewPager(view); setCurrentItem(initialPosition); } }