Java tutorial
/* * Copyright (C) 2011 The Android Open Source Project * 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.android.hcframe.view.tab; import android.content.Context; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.HorizontalScrollView; import android.widget.LinearLayout; import com.android.hcframe.HcUtil; import com.android.hcframe.R; import static android.view.ViewGroup.LayoutParams.MATCH_PARENT; import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT; /** * This widget implements the dynamic action bar tab behavior that can change * across different configurations or circumstances. */ public class HcTabPageIndicator extends HorizontalScrollView implements PageIndicator { /** * Interface for a callback when the selected tab has been reselected. */ public interface OnTabReselectedListener { /** * Callback when the selected tab has been reselected. * * @param position Position of the current center item. */ void onTabReselected(int position); } public abstract static class ViewHolderBase { private int mIndex; private void setIndex(int index) { mIndex = index; } private int getIndex() { return mIndex; } public abstract View createView(LayoutInflater layoutInflater, int position); public abstract void updateView(int position, boolean isCurrent); } public abstract static class ViewHolderCreator { public abstract ViewHolderBase createViewHolder(); } private ViewHolderCreator mViewHolderCreator; public void setViewHolderCreator(ViewHolderCreator viewHolderCreator) { mViewHolderCreator = viewHolderCreator; } private Runnable mTabSelector; private final OnClickListener mTabClickListener = new OnClickListener() { public void onClick(View view) { ViewHolderBase viewHolderBase = (ViewHolderBase) view.getTag(); final int oldSelected = mViewPager.getCurrentItem(); final int newSelected = viewHolderBase.getIndex(); mViewPager.setCurrentItem(newSelected); if (oldSelected == newSelected && mTabReselectedListener != null) { mTabReselectedListener.onTabReselected(newSelected); } } }; private final LinearLayout mTabLayout; private ViewPager mViewPager; private OnPageChangeListener mListener; private int mMaxTabWidth; private int mSelectedTabIndex = -1; private OnTabReselectedListener mTabReselectedListener; private int mCount; public HcTabPageIndicator(Context context) { this(context, null); } public HcTabPageIndicator(Context context, AttributeSet attrs) { super(context, attrs); setHorizontalScrollBarEnabled(false); mCount = context.getResources().getInteger(R.integer.config_tab_count); mTabLayout = new LinearLayout(context); addView(mTabLayout, new ViewGroup.LayoutParams(WRAP_CONTENT, MATCH_PARENT)); } /** * ?? * * @param count * @author jrjin * @time 2015-12-28 ?4:50:45 */ public void setVisibilityCount(int count) { mCount = count; } public void setOnTabReselectedListener(OnTabReselectedListener listener) { mTabReselectedListener = listener; } @Override public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { final int widthMode = MeasureSpec.getMode(widthMeasureSpec); final boolean lockedExpanded = widthMode == MeasureSpec.EXACTLY; setFillViewport(lockedExpanded); final int childCount = mTabLayout.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; } final int oldWidth = getMeasuredWidth(); super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int newWidth = getMeasuredWidth(); if (lockedExpanded && oldWidth != newWidth) { // Recenter the tab display if we're at a new (scrollable) size. updateTab(mSelectedTabIndex); } } private void animateToTab(final 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); } @Override public void onAttachedToWindow() { super.onAttachedToWindow(); if (mTabSelector != null) { // Re-post the selector we saved post(mTabSelector); } } @Override public void onDetachedFromWindow() { super.onDetachedFromWindow(); if (mTabSelector != null) { removeCallbacks(mTabSelector); } } @Override public void onPageScrollStateChanged(int i) { if (mListener != null) { mListener.onPageScrollStateChanged(i); } } @Override public void onPageScrolled(int i, float v, int i1) { if (mListener != null) { mListener.onPageScrolled(i, v, i1); } } @Override public void onPageSelected(int i) { if (mJumpPager != null) { mJumpPager.jumpPager(i); } moveToItem(i); } @Override public void setViewPager(ViewPager view) { if (mViewPager == view) { return; } if (mViewPager != null) { mViewPager.setOnPageChangeListener(null); } final PagerAdapter adapter = view.getAdapter(); if (adapter == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } mViewPager = view; view.setOnPageChangeListener(this); notifyDataSetChanged(); } public void notifyDataSetChanged() { mTabLayout.removeAllViews(); PagerAdapter adapter = mViewPager.getAdapter(); final int count = adapter.getCount(); LayoutInflater layoutInflater = LayoutInflater.from(this.getContext()); for (int i = 0; i < count; i++) { ViewHolderBase viewHolder = mViewHolderCreator.createViewHolder(); viewHolder.setIndex(i); View view = viewHolder.createView(layoutInflater, i); view.setFocusable(true); view.setOnClickListener(mTabClickListener); view.setTag(viewHolder); if (count > mCount) { mTabLayout.addView(view, new LinearLayout.LayoutParams(HcUtil.getScreenWidth() / mCount, MATCH_PARENT)); } else { mTabLayout.addView(view, new LinearLayout.LayoutParams(HcUtil.getScreenWidth() / count, MATCH_PARENT)); } } if (mSelectedTabIndex > count) { mSelectedTabIndex = count - 1; } moveToItem(mSelectedTabIndex); requestLayout(); } @Override public void setViewPager(ViewPager view, int initialPosition) { setViewPager(view); moveToItem(initialPosition); } public void moveToItem(int item) { if (mViewPager == null) { throw new IllegalStateException("ViewPager has not been bound."); } if (mSelectedTabIndex == item) { return; } mSelectedTabIndex = item; mViewPager.setCurrentItem(item); if (mListener != null) { mListener.onPageSelected(item); } updateTab(item); } private void updateTab(int item) { final int tabCount = mTabLayout.getChildCount(); for (int i = 0; i < tabCount; i++) { final View child = mTabLayout.getChildAt(i); final ViewHolderBase viewHolderBase = (ViewHolderBase) child.getTag(); final boolean isSelected = (i == item); viewHolderBase.updateView(i, isSelected); if (isSelected) { animateToTab(item); } } } @Override public void setOnPageChangeListener(OnPageChangeListener listener) { mListener = listener; } public static interface JumpPager { public void jumpPager(int position); } private JumpPager mJumpPager; public void setJumpPager(JumpPager jumpPager) { mJumpPager = jumpPager; } }