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.zhongsou.souyue.ui.indicator; 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.Gravity; import android.view.View; import android.view.ViewGroup; import android.widget.HorizontalScrollView; import android.widget.LinearLayout; import android.widget.TextView; import com.zhongsou.souyue.R; import static android.view.ViewGroup.LayoutParams.FILL_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 CheckTabPageIndicator extends HorizontalScrollView implements PageIndicator { /** * Title text used when no title is provided by the adapter. */ private static final CharSequence EMPTY_TITLE = ""; /** * 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; TextView tabView = (TextView) view; final int oldSelected = mViewPager.getCurrentItem(); // final int newSelected = tabView.getIndex(); final int newSelected = (Integer) tabView.getTag(); 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 int count; private OnTabReselectedListener mTabReselectedListener; public CheckTabPageIndicator(Context context) { this(context, null); } public CheckTabPageIndicator(Context context, AttributeSet attrs) { super(context, attrs); 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) { // final TabView tabView = new TabView(getContext()); // tabView.mIndex = index; final TextView tabView = new TextView(getContext()); tabView.setTag(index); if (index == 0) { doSetTextStyle(tabView, R.drawable.sy_indicator_icommentary_left); } else if (index == count - 1) { doSetTextStyle(tabView, R.drawable.sy_indicator_icommentary_right); } else { doSetTextStyle(tabView, R.drawable.sy_indicator_icommentary_middle); } tabView.setFocusable(true); tabView.setOnClickListener(mTabClickListener); tabView.setText(text); mTabLayout.addView(tabView, new LinearLayout.LayoutParams(0, FILL_PARENT, 1)); } @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(); 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); // } // } // // public int getIndex() { // return mIndex; // } // } private void doSetTextStyle(TextView tv, int background) { tv.setGravity(Gravity.CENTER); tv.setBackgroundResource(background); tv.setPadding(10, 12, 10, 12); tv.setTextSize(16); tv.setMaxLines(1); tv.setWidth(dip2px(this.getContext(), 110)); tv.setTextColor(0xff696969); } /** * ? dp ?? ? px(?) */ public static int dip2px(Context context, float dpValue) { final float scale = context.getResources().getDisplayMetrics().density; return (int) (dpValue * scale + 0.5f); } }