Java tutorial
/* * Copyright (C) 2011 The Android Open Source Project * Copyright (C) 2011 Jake Wharton * Copyright (C) 2012 Mariotaku Lee * * 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.afayear.android.client.view; import com.afayear.android.client.R; import com.afayear.android.client.view.iface.PagerIndicator; import com.afayear.android.util.ThemeUtils; import android.content.Context; import android.graphics.PorterDuff.Mode; import android.graphics.drawable.Drawable; import android.os.Build; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.text.TextUtils; import android.util.AttributeSet; import android.view.InputDevice; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.widget.FrameLayout; import android.widget.HorizontalScrollView; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.TextView; /** * This widget implements the dynamic action bar tab behavior that can change * across different configurations or circumstances. */ public class TabPageIndicator extends HorizontalScrollView implements PagerIndicator { private Runnable mTabSelector; private int mCurrentItem; private TabProvider mTabProvider; private TabListener mTabListener; private final LinearLayout mTabLayout; private ViewPager mViewPager; private ViewPager.OnPageChangeListener mPageListener; private final LayoutInflater mInflater; private final boolean mShouldApplyColorFilterToTabIcons; private final int mTabIconColor; int mMaxTabWidth; private int mSelectedTabIndex; private final int mTabColor; private boolean mSwitchingEnabled = true; private boolean mDisplayLabel, mDisplayIcon = true; private final OnClickListener mTabClickListener = new OnClickListener() { @Override public void onClick(final View view) { if (!mSwitchingEnabled) return; final TabView tabView = (TabView) view; if (mCurrentItem == tabView.getIndex() && mTabListener != null) { mTabListener.onPageReselected(mCurrentItem); } mCurrentItem = tabView.getIndex(); setCurrentItem(mCurrentItem); } }; private final OnLongClickListener mTabLongClickListener = new OnLongClickListener() { @Override public boolean onLongClick(final View view) { if (!mSwitchingEnabled) return false; final TabView tabView = (TabView) view; return mTabListener != null && mTabListener.onTabLongClick(tabView.getIndex()); } }; public TabPageIndicator(final Context context) { this(context, null); } public TabPageIndicator(final Context context, final AttributeSet attrs) { super(context, attrs); setHorizontalScrollBarEnabled(false); mTabColor = ThemeUtils.getThemeColor(context); mInflater = LayoutInflater.from(context); mTabLayout = new LinearLayout(context); mTabLayout.setShowDividers(LinearLayout.SHOW_DIVIDER_MIDDLE); mShouldApplyColorFilterToTabIcons = ThemeUtils.shouldApplyColorFilterToTabIcons(context); mTabIconColor = ThemeUtils.getTabIconColor(context); addView(mTabLayout, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.MATCH_PARENT)); } public int getTabCount() { return mTabLayout.getChildCount(); } public View getTabItem(final int position) { return mTabLayout.getChildAt(position); } public ViewGroup getTabLayout() { return mTabLayout; } @Override public void notifyDataSetChanged() { if (mTabLayout == null || mViewPager == null) return; mTabLayout.removeAllViews(); final PagerAdapter adapter = mViewPager.getAdapter(); mTabProvider = adapter instanceof TabProvider ? (TabProvider) adapter : null; mTabListener = adapter instanceof TabListener ? (TabListener) adapter : null; if (mTabProvider == null) return; final int count = adapter.getCount(); for (int i = 0; i < count; i++) { final CharSequence title = mTabProvider.getPageTitle(i); final Drawable icon = mTabProvider.getPageIcon(i); if (title != null && icon != null) { addTab(title, icon, i); } else if (title == null && icon != null) { addTab(null, icon, i); } else if (title != null && icon == null) { addTab(title, null, i); } } if (mSelectedTabIndex > count) { mSelectedTabIndex = count - 1; } setCurrentItem(mSelectedTabIndex); requestLayout(); } @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 boolean onGenericMotionEvent(final MotionEvent event) { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB_MR1) return false; if (mTabProvider == null) return false; if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) { switch (event.getAction()) { case MotionEvent.ACTION_SCROLL: { final float vscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL); if (vscroll < 0) { if (mCurrentItem + 1 < mTabProvider.getCount()) { setCurrentItem(mCurrentItem + 1); } } else if (vscroll > 0) { if (mCurrentItem - 1 >= 0) { setCurrentItem(mCurrentItem - 1); } } } } } return true; } @Override public void onMeasure(final int widthMeasureSpec, final 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. setCurrentItem(mSelectedTabIndex); } } @Override public void onPageScrolled(final int position, final float positionOffset, final int positionOffsetPixels) { if (mPageListener != null) { mPageListener.onPageScrolled(position, positionOffset, positionOffsetPixels); } } @Override public void onPageScrollStateChanged(final int state) { if (mPageListener != null) { mPageListener.onPageScrollStateChanged(state); } } @Override public void onPageSelected(final int position) { setCurrentItem(position); if (mTabListener != null) { mTabListener.onPageSelected(position); } if (mPageListener != null) { mPageListener.onPageSelected(position); } } @Override public void setCurrentItem(final int item) { if (mViewPager == null) return; // throw new IllegalStateException("ViewPager has not been bound."); mCurrentItem = item; mViewPager.setCurrentItem(item); mSelectedTabIndex = item; final int tabCount = mTabLayout.getChildCount(); for (int i = 0; i < tabCount; i++) { final View child = mTabLayout.getChildAt(i); final boolean isSelected = i == item; child.setSelected(isSelected); if (isSelected) { animateToTab(item); } } } public void setDisplayIcon(final boolean display) { mDisplayIcon = display; notifyDataSetChanged(); } public void setDisplayLabel(final boolean display) { mDisplayLabel = display; notifyDataSetChanged(); } @Override public void setEnabled(final boolean enabled) { super.setEnabled(enabled); setAlpha(enabled ? 1 : 0.5f); } @Override public void setOnPageChangeListener(final ViewPager.OnPageChangeListener listener) { mPageListener = listener; } public void setSwitchingEnabled(final boolean enabled) { if (!(mViewPager instanceof ViewPager)) throw new IllegalStateException( "This method should only called when your ViewPager instance is ExtendedViewPager"); mSwitchingEnabled = enabled; } @Override public void setViewPager(final ViewPager pager) { final PagerAdapter adapter = pager.getAdapter(); if (adapter == null) return; // throw new IllegalStateException("ViewPager has not been bound."); if (!(adapter instanceof TabProvider)) throw new IllegalStateException( "ViewPager adapter must implement TitleProvider to be used with TitlePageIndicator."); mViewPager = pager; pager.setOnPageChangeListener(this); notifyDataSetChanged(); } @Override public void setViewPager(final ViewPager pager, final int initialPosition) { setViewPager(pager); setCurrentItem(initialPosition); } private void addTab(final CharSequence label, final Drawable icon, final int index) { // Workaround for not being able to pass a defStyle on pre-3.0 final TabView tabView = (TabView) mInflater.inflate(R.layout.vpi__tab, null); tabView.init(this, mDisplayLabel ? label : null, mDisplayIcon ? icon : null, index); tabView.setFocusable(true); tabView.setOnClickListener(mTabClickListener); tabView.setOnLongClickListener(mTabLongClickListener); tabView.setContentDescription(label); mTabLayout.addView(tabView, new LinearLayout.LayoutParams(0, LayoutParams.MATCH_PARENT, 1)); if (ThemeUtils.shouldApplyColorFilter(getContext())) { ThemeUtils.applyBackground(tabView, mTabColor); } } private void animateToTab(final int position) { final View tabView = mTabLayout.getChildAt(position); if (mTabSelector != null) { removeCallbacks(mTabSelector); } mTabSelector = new Runnable() { @Override public void run() { final int scrollPos = tabView.getLeft() - (getWidth() - tabView.getWidth()) / 2; smoothScrollTo(scrollPos, 0); mTabSelector = null; } }; post(mTabSelector); } private int getTabIconColor() { return mTabIconColor; } private boolean shouldApplyColorFilterToTabIcons() { return mShouldApplyColorFilterToTabIcons; } public interface TabListener { public void onPageReselected(int position); public void onPageSelected(int position); public boolean onTabLongClick(int position); } /** * A TitleProvider provides the title to display according to a view. */ public interface TabProvider { public int getCount(); /** * Returns the icon of the view at position * * @param position * @return */ public Drawable getPageIcon(int position); /** * Returns the title of the view at position * * @param position * @return */ public CharSequence getPageTitle(int position); public float getPageWidth(int position); } public static class TabView extends FrameLayout { private TabPageIndicator mParent; private int mIndex; public TabView(final Context context, final AttributeSet attrs) { super(context, attrs); } public int getIndex() { return mIndex; } public void init(final TabPageIndicator parent, final CharSequence label, final Drawable icon, final int index) { if (isInEditMode()) return; mParent = parent; mIndex = index; final ImageView imageView = (ImageView) findViewById(R.id.tab_item_icon); imageView.setVisibility(icon != null ? View.VISIBLE : View.GONE); imageView.setImageDrawable(icon); if (parent.shouldApplyColorFilterToTabIcons()) { imageView.setColorFilter(parent.getTabIconColor(), Mode.SRC_ATOP); } final TextView textView = (TextView) findViewById(R.id.tab_item_title); textView.setVisibility(TextUtils.isEmpty(label) ? View.GONE : View.VISIBLE); textView.setText(label); } public void init(final TabPageIndicator parent, final CharSequence text, final int index) { init(parent, text, null, index); } public void init(final TabPageIndicator parent, final Drawable icon, final int index) { init(parent, null, icon, index); } @Override public void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // Re-measure if we went beyond our maximum size. if (!isInEditMode() && mParent.mMaxTabWidth > 0 && getMeasuredWidth() > mParent.mMaxTabWidth) { super.onMeasure(MeasureSpec.makeMeasureSpec(mParent.mMaxTabWidth, MeasureSpec.EXACTLY), heightMeasureSpec); } } } }