Java tutorial
package app.daeng.tokped.Utils; import android.content.Context; import android.graphics.Rect; 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.SparseArray; import android.util.TypedValue; import android.view.Gravity; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewTreeObserver; import android.widget.HorizontalScrollView; import android.widget.LinearLayout; import android.widget.TextView; /* * Copyright 2014 Google Inc. All rights reserved. * * 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. */ /** * 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...)}. 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); } private static final int TAB_VIEW_PADDING_DIPS = 16; private static final int TAB_VIEW_TEXT_SIZE_SP = 12; private int mTabViewLayoutId; private int mTabViewTextViewId; private boolean mDistributeEvenly; private ViewPager mViewPager; private SparseArray<String> mContentDescriptions = new SparseArray<String>(); 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); } public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // Disable the Scroll Bar setHorizontalScrollBarEnabled(false); // Make sure that the Tab Strips fills this View setFillViewport(true); mTabStrip = new SlidingTabStrip(context); //mTabStrip.setVisibility(View.INVISIBLE); addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT); getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { // Set spacer tab widths View firstTab = mTabStrip.getChildAt(0); int firstTabPadding = (getWidth() - mTabStrip.getChildAt(1).getMeasuredWidth()) / 2; firstTab.setPadding(firstTabPadding, firstTab.getPaddingTop(), firstTab.getPaddingRight(), firstTab.getPaddingBottom()); View lastTab = mTabStrip.getChildAt(mTabStrip.getChildCount() - 1); int lastTabPadding = (getWidth() - mTabStrip.getChildAt(mTabStrip.getChildCount() - 2).getMeasuredWidth()) / 4; lastTab.setPadding(lastTabPadding, 0, lastTabPadding, 0); if (Build.VERSION.SDK_INT > Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) getViewTreeObserver().removeOnGlobalLayoutListener(this); else getViewTreeObserver().removeGlobalOnLayoutListener(this); } }); } /** * Set the custom {@link TabColorizer} to be used. * <p/> * If you only require simple customisation then you can use * {@link #setSelectedIndicatorColors(int...)} to achieve * similar effects. */ public void setCustomTabColorizer(TabColorizer tabColorizer) { mTabStrip.setCustomTabColorizer(tabColorizer); } public void setDistributeEvenly(boolean distributeEvenly) { mDistributeEvenly = distributeEvenly; } /** * 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); } /** * 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)}. */ protected TextView createDefaultTabView(Context context) { 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.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); TypedValue outValue = new TypedValue(); getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true); textView.setBackgroundResource(outValue.resourceId); 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; } if (mDistributeEvenly) { LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView.getLayoutParams(); lp.width = 0; lp.weight = 1; } tabTitleView.setText(adapter.getPageTitle(i)); tabView.setOnClickListener(tabClickListener); String desc = mContentDescriptions.get(i, null); if (desc != null) { tabView.setContentDescription(desc); } mTabStrip.addView(tabView); if (i == mViewPager.getCurrentItem()) { tabView.setSelected(true); } } // First spacer tab TextView firstTab = new TextView(getContext()); mTabStrip.addView(firstTab, 0); // Last spacer tab TextView lastTab = new TextView(getContext()); mTabStrip.addView(lastTab); } public void setContentDescription(int i, String desc) { mContentDescriptions.put(i, desc); } private void scrollToTab(int tabIndex, int positionOffset) { final int tabStripChildCount = mTabStrip.getChildCount(); if (tabStripChildCount == 0 || tabIndex < 0 || tabIndex >= tabStripChildCount) { return; } if (positionOffset == -1) {// Not manual scroll. Do not animate. Just cut to tab and center. if (tabIndex == 1) positionOffset = 0; else positionOffset = mTabStrip.getChildAt(tabIndex).getWidth() / 2 + mTabStrip.getChildAt(tabIndex + 1).getWidth() / 2; } if (tabIndex == 1) // if tab number one, no need to calculate previously scrolled X scrollTo(positionOffset, 0); else { // If tab number is greater than 1, we need to calculate previously scrolled X int previouslyScrolledX = 0; // Simulate previously scrolled X by summing half of each of the previous tabs' width. // Use 2 tabs per loop for correct simulation. for (int i = 1; i < tabIndex; i++) { previouslyScrolledX += mTabStrip.getChildAt(i).getWidth() / 2; previouslyScrolledX += mTabStrip.getChildAt(i + 1).getWidth() / 2; } scrollTo(previouslyScrolledX + positionOffset, 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; } position++; // Offset position by 1 to make up for left blank tab mTabStrip.onViewPagerPageChanged(position, positionOffset); // Adding half of current tab's width & half of next tab's width and scrolling by that width will center next tab int offsetToCenterNextTab = (mTabStrip.getChildAt(position).getWidth() / 2) + (mTabStrip.getChildAt(position + 1).getWidth() / 2); scrollToTab(position, Math.round(offsetToCenterNextTab * positionOffset)); 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, -1); } for (int i = 0; i < mTabStrip.getChildCount(); i++) { mTabStrip.getChildAt(i).setSelected(position + 1 == i); } if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageSelected(position); } } } private class TabClickListener implements View.OnClickListener { @Override public void onClick(View selectedView) { View lastSelectedView = null; int selectedViewIndex = 0; for (int i = 1; i < mTabStrip.getChildCount() - 1; i++) { View currentViewInLoop = mTabStrip.getChildAt(i); if (currentViewInLoop.isSelected()) { lastSelectedView = currentViewInLoop; } if (selectedView == currentViewInLoop) { selectedViewIndex = i - 1; } if (lastSelectedView != null && selectedViewIndex != 0) break; } Rect tabContainerRect = new Rect(); Rect lastSelectedTabRect = new Rect(); getDrawingRect(tabContainerRect); lastSelectedView.getHitRect(lastSelectedTabRect); if (Rect.intersects(tabContainerRect, lastSelectedTabRect)) mViewPager.setCurrentItem(selectedViewIndex); else mViewPager.setCurrentItem(selectedViewIndex, false); } } }