Java tutorial
/* * Copyright (C) 2013 The Android Open Source Project * * 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.bryan.example.widget.slidingtablayout; import com.example.pratisemeanperfect.R; import android.R.integer; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Typeface; import android.os.Build; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.util.TypedValue; import android.view.Gravity; import android.view.LayoutInflater; import android.view.View; import android.widget.HorizontalScrollView; import android.widget.TextView; /** * To be used with ViewPager to provide a tab indicator component which give * constant feedback as to the user's scroll progress. * <p> * To use the component, simply add it to your view hierarchy. Then in your * {@link android.app.Activity} or {@link android.support.v4.app.Fragment} call * {@link #setViewPager(ViewPager)} providing it the ViewPager this layout is * being used for. * <p> * The colors can be customized in two ways. The first and simplest is to * provide an array of colors via {@link #setSelectedIndicatorColors(int...)} * and {@link #setDividerColors(int...)}. The alternative is via the * {@link TabColorizer} interface which provides you complete control over which * color is used for any individual position. * <p> * The views used as tabs can be customized by calling * {@link #setCustomTabView(int, int)}, providing the layout ID of your custom * layout. */ public class SlidingTabLayout extends HorizontalScrollView { /** * Allows complete control over the colors drawn in the tab layout. Set with * {@link #setCustomTabColorizer(TabColorizer)}. */ public interface TabColorizer { /** * @return return the color of the indicator used when {@code position} * is selected. */ int getIndicatorColor(int position); /** * @return return the color of the divider drawn to the right of * {@code position}. */ int getDividerColor(int position); } private static final int TITLE_OFFSET_DIPS = 24; private static final int TAB_VIEW_PADDING_DIPS = 16; private static final int TAB_VIEW_TEXT_SIZE_SP = 12; private int mTitleOffset; private int mTabViewLayoutId; private int mTabViewTextViewId; private ViewPager mViewPager; private ViewPager.OnPageChangeListener mViewPagerPageChangeListener; private final SlidingTabStrip mTabStrip; public SlidingTabLayout(Context context) { this(context, null); } public SlidingTabLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); } /** * ??? */ private int mDefaultTextColor; private int mSelectedTextColor; public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); /** * ?? */ TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SlidingTabLayout); int defaultTextColor = a.getColor(R.styleable.SlidingTabLayout_android_textColorPrimary, 0); mDefaultTextColor = a.getColor(R.styleable.SlidingTabLayout_textColorTabDefault, defaultTextColor); mSelectedTextColor = a.getColor(R.styleable.SlidingTabLayout_textColorTabSelected, defaultTextColor); a.recycle(); // ?? setHorizontalScrollBarEnabled(false); // ??? setFillViewport(true); mTitleOffset = (int) (TITLE_OFFSET_DIPS * getResources().getDisplayMetrics().density); mTabStrip = new SlidingTabStrip(context); addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT); } /** * ??? */ private void updateSelectedTitle(int position) { final PagerAdapter adapter = mViewPager.getAdapter(); for (int i = 0; i < adapter.getCount(); i++) { final View tabView = mTabStrip.getChildAt(i); if (TextView.class.isInstance(tabView)) { TextView titleView = (TextView) tabView; boolean isSelected = i == position; titleView.setTextColor(isSelected ? mSelectedTextColor : mDefaultTextColor); } } } /** * Set the custom {@link TabColorizer} to be used. * * If you only require simple custmisation then you can use * {@link #setSelectedIndicatorColors(int...)} and * {@link #setDividerColors(int...)} to achieve similar effects. */ public void setCustomTabColorizer(TabColorizer tabColorizer) { mTabStrip.setCustomTabColorizer(tabColorizer); } /** * Sets the colors to be used for indicating the selected tab. These colors * are treated as a circular array. Providing one color will mean that all * tabs are indicated with the same color. */ public void setSelectedIndicatorColors(int... colors) { mTabStrip.setSelectedIndicatorColors(colors); } /** * Sets the colors to be used for tab dividers. These colors are treated as * a circular array. Providing one color will mean that all tabs are * indicated with the same color. */ public void setDividerColors(int... colors) { mTabStrip.setDividerColors(colors); } /** * Set the {@link ViewPager.OnPageChangeListener}. When using * {@link SlidingTabLayout} you are required to set any * {@link ViewPager.OnPageChangeListener} through this method. This is so * that the layout can update it's scroll position correctly. * * @see ViewPager#setOnPageChangeListener(ViewPager.OnPageChangeListener) */ public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) { mViewPagerPageChangeListener = listener; } /** * Set the custom layout to be inflated for the tab views. * * @param layoutResId * Layout id to be inflated * @param textViewId * id of the {@link TextView} in the inflated view */ public void setCustomTabView(int layoutResId, int textViewId) { mTabViewLayoutId = layoutResId; mTabViewTextViewId = textViewId; } /** * Sets the associated view pager. Note that the assumption here is that the * pager content (number of tabs and tab titles) does not change after this * call has been made. */ public void setViewPager(ViewPager viewPager) { mTabStrip.removeAllViews(); mViewPager = viewPager; if (viewPager != null) { viewPager.setOnPageChangeListener(new InternalViewPagerListener()); populateTabStrip(); } } /** * Create a default view to be used for tabs. This is called if a custom tab * view is not set via {@link #setCustomTabView(int, int)}. */ @SuppressLint("NewApi") protected TextView createDefaultTabView(Context context) { /** * ?Holo?? */ TextView textView = new TextView(context); textView.setGravity(Gravity.CENTER); textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, TAB_VIEW_TEXT_SIZE_SP); // textView.setTypeface(Typeface.DEFAULT_BOLD);// textView.setTypeface(Typeface.DEFAULT); // if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) // { // // If we're running on Honeycomb or newer, then we can use the // // Theme's // // selectableItemBackground to ensure that the View has a pressed // // state // TypedValue outValue = new TypedValue(); // getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, // outValue, true); // textView.setBackgroundResource(outValue.resourceId); // } if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { // If we're running on ICS or newer, enable all-caps to match the // Action Bar tab style textView.setAllCaps(true); } int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density); textView.setPadding(padding, padding, padding, padding); return textView; } private void populateTabStrip() { final PagerAdapter adapter = mViewPager.getAdapter(); final View.OnClickListener tabClickListener = new TabClickListener(); for (int i = 0; i < adapter.getCount(); i++) { View tabView = null; TextView tabTitleView = null; if (mTabViewLayoutId != 0) { // If there is a custom tab view layout id set, try and inflate // it tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip, false); tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId); } if (tabView == null) { tabView = createDefaultTabView(getContext()); } if (tabTitleView == null && TextView.class.isInstance(tabView)) { tabTitleView = (TextView) tabView; } tabTitleView.setText(adapter.getPageTitle(i)); tabView.setOnClickListener(tabClickListener); mTabStrip.addView(tabView); } } @Override protected void onAttachedToWindow() { super.onAttachedToWindow(); if (mViewPager != null) { scrollToTab(mViewPager.getCurrentItem(), 0); } } private void scrollToTab(int tabIndex, int positionOffset) { final int tabStripChildCount = mTabStrip.getChildCount(); if (tabStripChildCount == 0 || tabIndex < 0 || tabIndex >= tabStripChildCount) { return; } View selectedChild = mTabStrip.getChildAt(tabIndex); if (selectedChild != null) { //?? updateSelectedTitle(tabIndex); int targetScrollX = selectedChild.getLeft() + positionOffset; if (tabIndex > 0 || positionOffset > 0) { // If we're not at the first child and are mid-scroll, make sure // we obey the offset //????????? targetScrollX -= mTitleOffset; } scrollTo(targetScrollX, 0); } } private class InternalViewPagerListener implements ViewPager.OnPageChangeListener { private int mScrollState; @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { int tabStripChildCount = mTabStrip.getChildCount(); if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) { return; } mTabStrip.onViewPagerPageChanged(position, positionOffset); View selectedTitle = mTabStrip.getChildAt(position); int extraOffset = (selectedTitle != null) ? (int) (positionOffset * selectedTitle.getWidth()) : 0; scrollToTab(position, extraOffset); if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageScrolled(position, positionOffset, positionOffsetPixels); } } @Override public void onPageScrollStateChanged(int state) { mScrollState = state; if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageScrollStateChanged(state); } } @Override public void onPageSelected(int position) { if (mScrollState == ViewPager.SCROLL_STATE_IDLE) { mTabStrip.onViewPagerPageChanged(position, 0f); scrollToTab(position, 0); } if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageSelected(position); } } } private class TabClickListener implements View.OnClickListener { @Override public void onClick(View v) { for (int i = 0; i < mTabStrip.getChildCount(); i++) { if (v == mTabStrip.getChildAt(i)) { mViewPager.setCurrentItem(i); return; } } } } }