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.byteridge.bookcircle.ui; import static android.view.ViewGroup.LayoutParams.FILL_PARENT; import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT; import android.content.Context; import android.graphics.Color; 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.util.DisplayMetrics; import android.view.View; import android.view.ViewGroup; import android.view.WindowManager; import android.widget.HorizontalScrollView; import android.widget.LinearLayout; import android.widget.TableLayout; import android.widget.TextView; import com.byteridge.bookcircle.R; /** * This widget implements the dynamic action bar tab behavior that can change across different configurations or circumstances. */ public class TabPageIndicator extends HorizontalScrollView implements PageIndicator { /** Title text used when no title is provided by the adapter. */ private static final CharSequence EMPTY_TITLE = "Tabs"; private Context ctx; /** * 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); } private Runnable mTabSelector; private final OnClickListener mTabClickListener = new OnClickListener() { public void onClick(View view) { TabView tabView = (TabView) view; final int oldSelected = mViewPager.getCurrentItem(); final int newSelected = tabView.getIndex(); mViewPager.setCurrentItem(newSelected); if (oldSelected == newSelected && mTabReselectedListener != null) { mTabReselectedListener.onTabReselected(newSelected); } } }; private final LinearLayout mTabLayout; private ViewPager mViewPager; private ViewPager.OnPageChangeListener mListener; private int mMaxTabWidth; private int mSelectedTabIndex; private OnTabReselectedListener mTabReselectedListener; public TabPageIndicator(Context context) { this(context, null); ctx = context; } public TabPageIndicator(Context context, AttributeSet attrs) { super(context, attrs); ctx = context; setHorizontalScrollBarEnabled(false); mTabLayout = new LinearLayout(getContext()); addView(mTabLayout, new ViewGroup.LayoutParams(WRAP_CONTENT, FILL_PARENT)); } 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. setCurrentItem(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); } } private void addTab(CharSequence text, int index) { // text = "Tab " + index; final TabView tabView = new TabView(getContext()); tabView.mIndex = index; tabView.setFocusable(true); tabView.setOnClickListener(mTabClickListener); tabView.setText(text); WindowManager wm = (WindowManager) ctx.getSystemService(Context.WINDOW_SERVICE); DisplayMetrics displaymetrics = new DisplayMetrics(); wm.getDefaultDisplay().getMetrics(displaymetrics); int width = displaymetrics.widthPixels; tabView.setWidth(width / 3); tabView.setTextColor(Color.BLACK); tabView.setTextSize(13); // tabView.setShadowLayer(1, 1, 1, Color.WHITE); // tabView.setTypeface(GreatBuyzApplication.getApplication().getFont()); // ,Typeface.BOLD); tabView.setLayoutParams( new TableLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 1f)); mTabLayout.addView(tabView, new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WRAP_CONTENT, 1f)); } @Override public void onPageScrollStateChanged(int arg0) { if (mListener != null) { mListener.onPageScrollStateChanged(arg0); } } @Override public void onPageScrolled(int arg0, float arg1, int arg2) { if (mListener != null) { mListener.onPageScrolled(arg0, arg1, arg2); } } @Override public void onPageSelected(int arg0) { setCurrentItem(arg0); if (mListener != null) { mListener.onPageSelected(arg0); } } @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(); for (int i = 0; i < count; i++) { CharSequence title = adapter.getPageTitle(i); if (title == null) { title = EMPTY_TITLE; } addTab(title, i); } if (mSelectedTabIndex > count) { mSelectedTabIndex = count - 1; } setCurrentItem(mSelectedTabIndex); requestLayout(); } @Override public void setViewPager(ViewPager view, int initialPosition) { setViewPager(view); setCurrentItem(initialPosition); } @Override public void setCurrentItem(int item) { if (mViewPager == null) { throw new IllegalStateException("ViewPager has not been bound."); } mSelectedTabIndex = item; mViewPager.setCurrentItem(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); } } } @Override public void setOnPageChangeListener(OnPageChangeListener listener) { mListener = listener; } private class TabView extends TextView { private int mIndex; public TabView(Context context) { super(context, null, R.attr.vpiTabPageIndicatorStyle); } @Override public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // Re-measure if we went beyond our maximum size. /* * if (mMaxTabWidth > 0 && getMeasuredWidth() > mMaxTabWidth) { super.onMeasure(MeasureSpec.makeMeasureSpec(mMaxTabWidth, MeasureSpec.EXACTLY), heightMeasureSpec); } */ super.onMeasure(MeasureSpec.makeMeasureSpec(MeasureSpec.AT_MOST, MeasureSpec.EXACTLY), heightMeasureSpec); } public int getIndex() { return mIndex; } } public void setHorizontalFadingEdgeEnabled(boolean horizontalFadingEdgeEnabled) { super.setHorizontalFadingEdgeEnabled(horizontalFadingEdgeEnabled); } @Override public void setScrollBarStyle(int style) { super.setScrollBarStyle(style); } @Override public void setHorizontalScrollBarEnabled(boolean horizontalScrollBarEnabled) { super.setHorizontalScrollBarEnabled(horizontalScrollBarEnabled); } @Override public int getCurrentItem() { // TODO Auto-generated method stub return mSelectedTabIndex; } }