Java tutorial
package com.jun.fakeoschina.widget; /* * Copyright (C) 2013 Peng fei Pan <sky@xiaopan.me> * * 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 java.util.ArrayList; import java.util.Iterator; import java.util.List; import android.content.Context; import android.support.v4.content.ContextCompat; import android.util.AttributeSet; import android.widget.HorizontalScrollView; import android.graphics.Canvas; import android.graphics.drawable.Drawable; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.view.View; import android.view.ViewGroup; import android.widget.LinearLayout; import com.jun.fakeoschina.R; /** * ViewPager? HOME * * @version 1.3.0 * @author Peng fei Pan */ public class PagerSlidingTabStrip extends HorizontalScrollView implements View.OnClickListener { private int currentPosition; // ?? private int lastOffset; private int lastScrollX = 0; private float currentPositionOffset; // ????? private boolean start; private boolean allowWidthFull; // ?Item private boolean disableViewPager; // ?ViewPager private View currentSelectedTabView; // ? private Drawable slidingBlockDrawable; // ? private ViewPager viewPager; // ViewPager private ViewGroup tabsLayout; // private ViewPager.OnPageChangeListener onPageChangeListener; // ??? private OnClickTabListener onClickTabListener; private OnPagerChangeLis listener; private List<View> tabViews; public PagerSlidingTabStrip(Context context) { this(context, null); } public PagerSlidingTabStrip(Context context, AttributeSet attrs) { super(context, attrs); setHorizontalScrollBarEnabled(false); // ?????? if (attrs != null) { // TypedArray attrsTypedArray = context.obtainStyledAttributes(attrs, // R.styleable.PagerSlidingTabStrip); // if (attrsTypedArray != null) { allowWidthFull = true; //?drawable slidingBlockDrawable = ContextCompat.getDrawable(getContext(), R.drawable.image_sliding_block); disableViewPager = false; // attrsTypedArray.recycle(); // } } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (!allowWidthFull) return; ViewGroup tabsLayout = getTabsLayout(); // tabsLayout.getMeasuredWidth() ? 528 // getMeasuredWidth() pagerSlidingTabStrip xml720 android:layout_width="match_parent" if (tabsLayout == null || tabsLayout.getMeasuredWidth() >= getMeasuredWidth()) return; if (tabsLayout.getChildCount() <= 0) return; if (tabViews == null) { tabViews = new ArrayList<View>(); } else { tabViews.clear(); } for (int w = 0; w < tabsLayout.getChildCount(); w++) { tabViews.add(tabsLayout.getChildAt(w)); } adjustChildWidthWithParent(tabViews, getMeasuredWidth() - tabsLayout.getPaddingLeft() - tabsLayout.getPaddingRight(), widthMeasureSpec, heightMeasureSpec); super.onMeasure(widthMeasureSpec, heightMeasureSpec); } /** * views?ViewView?parentViewWidth * * @param views * ?View? * @param parentViewWidth * Vie * @param parentWidthMeasureSpec * View * @param parentHeightMeasureSpec * View */ private void adjustChildWidthWithParent(List<View> views, int parentViewWidth, int parentWidthMeasureSpec, int parentHeightMeasureSpec) { // ?View? for (View view : views) { if (view.getLayoutParams() instanceof MarginLayoutParams) { LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) view.getLayoutParams(); parentViewWidth -= lp.leftMargin + lp.rightMargin; } } // ?View??? int averageWidth = parentViewWidth / views.size(); int bigTabCount = views.size(); while (true) { Iterator<View> iterator = views.iterator(); while (iterator.hasNext()) { View view = iterator.next(); if (view.getMeasuredWidth() > averageWidth) { parentViewWidth -= view.getMeasuredWidth(); bigTabCount--; iterator.remove(); } } averageWidth = parentViewWidth / bigTabCount; boolean end = true; for (View view : views) { if (view.getMeasuredWidth() > averageWidth) { end = false; } } if (end) { break; } } // ??View for (View view : views) { if (view.getMeasuredWidth() < averageWidth) { LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) view.getLayoutParams(); layoutParams.width = averageWidth; view.setLayoutParams(layoutParams); // ?? if (layoutParams instanceof MarginLayoutParams) { measureChildWithMargins(view, parentWidthMeasureSpec, 0, parentHeightMeasureSpec, 0); } else { measureChild(view, parentWidthMeasureSpec, parentHeightMeasureSpec); } } } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { super.onLayout(changed, l, t, r, b); ViewGroup tabViewGroup = getTabsLayout(); if (tabViewGroup != null) { // ????? currentPosition = viewPager != null ? viewPager.getCurrentItem() : 0; if (!disableViewPager) { scrollToChild(currentPosition, 0); // ?? selectedTab(currentPosition); // ?TAB } // ?tab?Pager for (int w = 0; w < tabViewGroup.getChildCount(); w++) { View itemView = tabViewGroup.getChildAt(w); itemView.setTag(w); itemView.setOnClickListener(this); } } } @Override public void onClick(View v) { int index = (Integer) v.getTag(); if (onClickTabListener != null) { onClickTabListener.onClickTab(v, index); } if (viewPager != null) { viewPager.setCurrentItem(index, true); } } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (disableViewPager) return; /* ? */ ViewGroup tabsLayout = getTabsLayout(); if (tabsLayout != null && tabsLayout.getChildCount() > 0 && slidingBlockDrawable != null) { View currentTab = tabsLayout.getChildAt(currentPosition); if (currentTab != null) { float slidingBlockLeft = currentTab.getLeft(); float slidingBlockRight = currentTab.getRight(); if (currentPositionOffset > 0f && currentPosition < tabsLayout.getChildCount() - 1) { View nextTab = tabsLayout.getChildAt(currentPosition + 1); if (nextTab != null) { final float nextTabLeft = nextTab.getLeft(); final float nextTabRight = nextTab.getRight(); slidingBlockLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) * slidingBlockLeft); slidingBlockRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) * slidingBlockRight); } } slidingBlockDrawable.setBounds((int) slidingBlockLeft, 0, (int) slidingBlockRight, getHeight()); slidingBlockDrawable.draw(canvas); } } } /** * ? */ private ViewGroup getTabsLayout() { if (tabsLayout == null) { if (getChildCount() > 0) { tabsLayout = (ViewGroup) getChildAt(0); } else { removeAllViews(); tabsLayout = new LinearLayout(getContext()); addView(tabsLayout, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); } } return tabsLayout; } /** * ? */ private void scrollToChild(int position, int offset) { ViewGroup tabsLayout = getTabsLayout(); if (tabsLayout != null && tabsLayout.getChildCount() > 0 && position < tabsLayout.getChildCount()) { View view = tabsLayout.getChildAt(position); if (view != null) { // X?? int newScrollX = view.getLeft() + offset; if (position > 0 || offset > 0) { newScrollX -= 240 - getOffset(view.getWidth()) / 2; } // ?X??? if (newScrollX != lastScrollX) { lastScrollX = newScrollX; scrollTo(newScrollX, 0); } } } } /** * ???? */ private int getOffset(int newOffset) { if (lastOffset < newOffset) { if (start) { lastOffset += 1; return lastOffset; } else { start = true; lastOffset += 1; return lastOffset; } } if (lastOffset > newOffset) { if (start) { lastOffset -= 1; return lastOffset; } else { start = true; lastOffset -= 1; return lastOffset; } } else { start = true; lastOffset = newOffset; return lastOffset; } } /** * ?TAB */ private void selectedTab(int currentSelectedTabPosition) { ViewGroup tabsLayout = getTabsLayout(); if (currentSelectedTabPosition > -1 && tabsLayout != null && currentSelectedTabPosition < tabsLayout.getChildCount()) { if (currentSelectedTabView != null) { currentSelectedTabView.setSelected(false); } currentSelectedTabView = tabsLayout.getChildAt(currentSelectedTabPosition); if (currentSelectedTabView != null) { currentSelectedTabView.setSelected(true); } } } /** * Tab */ public void addTab(View tabView, int index) { if (tabView != null) { getTabsLayout().addView(tabView, index); requestLayout(); } } /** * Tab */ public void addTab(View tabView) { addTab(tabView, -1); } /** * Tab * * @param tabViews * ?Tab */ public void addTab(View... tabViews) { if (tabViews != null) { for (View view : tabViews) { getTabsLayout().addView(view); } requestLayout(); } } /** * Tab */ public void addTab(List<View> tabViews) { if (tabViews != null) { for (View view : tabViews) { getTabsLayout().addView(view); } requestLayout(); } } /** * tab * * @param index */ public void removeTab(int index) { removeTab(index, 1); } /** * tab * * @param start ? * @param count ? */ public void removeTab(int start, int count) { int tabCount = getTabCount(); if (start < 0 || start > tabCount) { start = 0; } if (count < 0 || count > tabCount) { count = 1; } if (count - start > tabCount) { count = tabCount - start; } getTabsLayout().removeViews(start, count); requestLayout(); } /** * */ public void removeAllTab() { getTabsLayout().removeAllViews(); requestLayout(); } public View getChild(int idx) { return getTabsLayout().getChildAt(idx); } // public View getBadgeView(int i) { // return getTabsLayout().getChildAt(i).findViewById(R.id.tab_mes); // } /** * ViewPager * * @param viewPager * ViewPager */ public void setViewPager(ViewPager viewPager) { if (disableViewPager) return; this.viewPager = viewPager; this.viewPager.setOnPageChangeListener(new OnPageChangeListener() { @Override public void onPageSelected(int position) { selectedTab(position); if (onPageChangeListener != null) { onPageChangeListener.onPageSelected(position); } if (listener != null) listener.onChanged(position); } @Override public void onPageScrolled(int nextPagePosition, float positionOffset, int positionOffsetPixels) { ViewGroup tabsLayout = getTabsLayout(); if (nextPagePosition < tabsLayout.getChildCount()) { View view = tabsLayout.getChildAt(nextPagePosition); if (view != null) { currentPosition = nextPagePosition; currentPositionOffset = positionOffset; scrollToChild(nextPagePosition, (int) (positionOffset * view.getWidth())); invalidate(); } } if (onPageChangeListener != null) { onPageChangeListener.onPageScrolled(nextPagePosition, positionOffset, positionOffsetPixels); } } @Override public void onPageScrollStateChanged(int arg0) { if (onPageChangeListener != null) { onPageChangeListener.onPageScrollStateChanged(arg0); } } }); requestLayout(); } /** * Page?? * * @param onPageChangeListener * Page?? */ public void setOnPageChangeListener(OnPageChangeListener onPageChangeListener) { this.onPageChangeListener = onPageChangeListener; } /** * ?? * * @param allowWidthFull * true??Item? */ public void setAllowWidthFull(boolean allowWidthFull) { this.allowWidthFull = allowWidthFull; requestLayout(); } /** * ? */ public void setSlidingBlockDrawable(Drawable slidingBlockDrawable) { this.slidingBlockDrawable = slidingBlockDrawable; requestLayout(); } /** * ?Tab */ public int getTabCount() { ViewGroup tabsLayout = getTabsLayout(); return tabsLayout != null ? tabsLayout.getChildCount() : 0; } /** * Tab? * * @param onClickTabListener * Tab? */ public void setOnClickTabListener(OnClickTabListener onClickTabListener) { this.onClickTabListener = onClickTabListener; } /** * ?ViewPager * * @param disableViewPager * ?ViewPager */ public void setDisableViewPager(boolean disableViewPager) { this.disableViewPager = disableViewPager; if (viewPager != null) { viewPager.setOnPageChangeListener(onPageChangeListener); viewPager = null; } requestLayout(); } /** * Tab? * * @author xiaopan * */ public interface OnClickTabListener { public void onClickTab(View tab, int index); } public void setOnPagerChange(OnPagerChangeLis l) { this.listener = l; } public interface OnPagerChangeLis { void onChanged(int page); } }