AndroidUI组件SlidingTabLayout实现ViewPager页滑动效果

/*
 * 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.example.my.slidingtablayout;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Color;
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.LinearLayout;
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; //内边距
 private static int TAB_VIEW_TEXT_SIZE_SP = 16; //字体大小

 privatE int mtitleOffset;

 privatE int mTabViewLayoutId;
 privatE int mTabViewTextViewId;

 // 定义两种需要添加的选项卡颜色
 privatE int mDefaultTextColor;
 privatE int mSELEctedTextColor;

 private ViewPager mViewPager;
 private ViewPager.onPage@L_197_11@ener mViewPagerPage@L_197_11@ener;

 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,defStylE);

  // 获取选项卡颜色，如果未定义的话，则使用主题默认的颜色
  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();


  // Disable the Scroll Bar
  setHorizontalScrollBarEnabled(false);
  // Make sure that the Tab Strips fills this View
  setFillViewport(true);

  mtitleOffset = (int) (titlE_OFFSET_DIPS * getresources().getDisplaymetrics().density);

  mTabStrip = new SlidingTabStrip(context);
  addView(mTabStrip,LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT);
 }

 // 在每次选项改变时更新选项卡文本颜色的新@L_944_17@
 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.
  * <p>
  * 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);
 }

 //...设置字体大小
 public void settitleSize(int sizE) {
  this.TAB_VIEW_TEXT_SIZE_SP = size;
 }

 /**
  * Set the {@link ViewPager.onPage@L_197_11@ener}. When using {@link SlidingTabLayout} you are
  * required to set any {@link ViewPager.onPage@L_197_11@ener} through this method. This is so
  * that the layout can update it's scroll position correctly.
  *
  * @see ViewPager#setOnPage@L_197_11@ener(ViewPager.onPage@L_197_11@ener)
  */
 public void setOnPage@L_197_11@ener(ViewPager.onPage@L_197_11@ener listener) {
  mViewPagerPage@L_197_11@ener = 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.setOnPage@L_197_11@ener(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);

  //...这会移除 Holo 的默认背景强调以及选项卡的粗体文本
  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);

  return textView;
 }

 private void populateTabStrip() {
  final PagerAdapter adapter = mViewPager.getAdapter();
  final 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));
   //... 设置头部均分
   LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(0,LayoutParams.WRAP_CONTENT,1.0f);
   tabView.setLayoutParams(layoutParams);
   tabView.setOnClickListener(tabClickListener);

   mTabStrip.addView(tabView);
  }
 }

 @Override
 protected void onAttachedToWindow() {
  super.onAttachedToWindow();

  if (mViewPager != null) {
   scroll@R_187_10586@b(mViewPager.getCurrentItem(),0);
  }
 }

 private void scroll@R_187_10586@b(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) {

   // 调用在每次选项改变时更新文本颜色的新方案
   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.onPage@L_197_11@ener {
  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;
   scroll@R_187_10586@b(position,extraOffset);

   if (mViewPagerPage@L_197_11@ener != null) {
    mViewPagerPage@L_197_11@ener.onPageScrolled(position,positionOffset,positionOffsetPixels);
   }
  }

  @Override
  public void onPageScrollStateChanged(int statE) {
   mScrollState = state;

   if (mViewPagerPage@L_197_11@ener != null) {
    mViewPagerPage@L_197_11@ener.onPageScrollStateChanged(statE);
   }
  }

  @Override
  public void onPageSELEcted(int position) {
   if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
    mTabStrip.onViewPagerPageChanged(position,0f);
    scroll@R_187_10586@b(position,0);
   }

   if (mViewPagerPage@L_197_11@ener != null) {
    mViewPagerPage@L_197_11@ener.onPageSELEcted(position);
   }
  }

 }

 private class TabClickListener implements OnClickListener {
  @Override
  public void onClick(View v) {
   for (int i = 0; i < mTabStrip.getChildCount(); i++) {
    if (v == mTabStrip.getChildAt(i)) {
     mViewPager.setCurrentItem(i);
     return;
    }
   }
  }
 }

}

/*
 * Copyright (C) 2013 The Android open source Project
 *
 * Licensed under the Apache License,either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.my.slidingtablayout;

import android.R;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
import android.widget.LinearLayout;

class SlidingTabStrip extends LinearLayout {

 private static final int DEFAULT_BOTTOM_BORDER_THICKnesS_DIPS = 0; //去除阴影
 private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26;
 private static final int SELECTED_INDicATOR_THICKnesS_DIPS = 4;  //设置滚动条的高度
 private static final int DEFAULT_SELECTED_INDicATOR_COLOR = 0xFF33B5E5;


 private static final int DEFAULT_DIVIDER_THICKnesS_DIPS = 1;
 private static final byte DEFAULT_DIVIDER_COLOR_ALPHA = 0x20;
 private static final float DEFAULT_DIVIDER_HEIGHT = 0.5f;

 private final int mBottomBorderThickness;
 private final Paint mBottomBorderPaint;

 private final int mSELEctedInDicatorThickness;
 private final Paint mSELEctedInDicatorPaint;

 private final int mDefaultBottomBorderColor;

 private final Paint mDividerPaint;
 private final float mDividerHeight;

 privatE int mSELEctedPosition;
 private float mSELEctionOffset;

 private SlidingTabLayout.TabColorizer mCustomTabColorizer;
 private final SimpleTabColorizer mDefaultTabColorizer;

 SlidingTabStrip(Context context) {
  this(context,null);
 }

 SlidingTabStrip(Context context,AttributeSet attrs) {
  super(context,attrs);
  setWillNotDraw(false);

  final float density = getresources().getDisplaymetrics().density;

  TypedValue outValue = new TypedValue();
  context.getTheme().resolveAttribute(R.attr.colorForeground,truE);
  final int themeForegroundColor = outValue.data;

  mDefaultBottomBorderColor = setColorAlpha(themeForegroundColor,DEFAULT_BOTTOM_BORDER_COLOR_ALPHA);

  mDefaultTabColorizer = new SimpleTabColorizer();
  mDefaultTabColorizer.seTinDicatorColors(DEFAULT_SELECTED_INDicATOR_COLOR);
  mDefaultTabColorizer.setDividerColors(setColorAlpha(themeForegroundColor,DEFAULT_DIVIDER_COLOR_ALPHA));

  mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKnesS_DIPS * density);
  mBottomBorderPaint = new Paint();
  mBottomBorderPaint.setColor(mDefaultBottomBorderColor);

  mSELEctedInDicatorThickness = (int) (SELECTED_INDicATOR_THICKnesS_DIPS * density);
  mSELEctedInDicatorPaint = new Paint();

  mDividerHeight = DEFAULT_DIVIDER_HEIGHT;
  mDividerPaint = new Paint();
  mDividerPaint.setstrokeWidth((int) (DEFAULT_DIVIDER_THICKnesS_DIPS * density));
 }

 void setCustomTabColorizer(SlidingTabLayout.TabColorizer customTabColorizer) {
  mCustomTabColorizer = customTabColorizer;
  invalidate();
 }

 void setSELEctedInDicatorColors(int... colors) {
  // Make sure that the custom colorizer is removed
  mCustomTabColorizer = null;
  mDefaultTabColorizer.seTinDicatorColors(colors);
  invalidate();
 }

 void setDividerColors(int... colors) {
  // Make sure that the custom colorizer is removed
  mCustomTabColorizer = null;
  mDefaultTabColorizer.setDividerColors(colors);
  invalidate();
 }

 void onViewPagerPageChanged(int position,float positionOffset) {
  mSELEctedPosition = position;
  mSELEctionOffset = positionOffset;
  invalidate();
 }

 @Override
 protected void onDraw(Canvas canvas) {
  final int height = getHeight();
  final int childCount = getChildCount();
  final int dividerHeightPx = (int) (Math.min(Math.max(0f,mDividerHeight),1f) * height);
  final SlidingTabLayout.TabColorizer tabColorizer = mCustomTabColorizer != null
    ? mCustomTabColorizer
    : mDefaultTabColorizer;

  // Thick colored underline below the current SELEction
  if (childCount > 0) {
   View SELEctedtitle = getChildAt(mSELEctedPosition);
   int left = SELEctedtitle.getLeft();
   int right = SELEctedtitle.getright();
   int color = tabColorizer.geTinDicatorColor(mSELEctedPosition);

   if (mSELEctionOffset > 0f && mSELEctedPosition < (getChildCount() - 1)) {
    int nextColor = tabColorizer.geTinDicatorColor(mSELEctedPosition + 1);
    if (color != nextColor) {
     color = blendColors(nextColor,color,mSELEctionOffset);
    }

    // Draw the SELEction partway between the tabs
    View nexttitle = getChildAt(mSELEctedPosition + 1);
    left = (int) (mSELEctionOffset * nexttitle.getLeft() +
      (1.0f - mSELEctionOffset) * left);
    right = (int) (mSELEctionOffset * nexttitle.getright() +
      (1.0f - mSELEctionOffset) * right);
   }

   mSELEctedInDicatorPaint.setColor(color);

   canvas.drawRect(left,height - mSELEctedInDicatorThickness,right,height,mSELEctedInDicatorPaint);
  }

  // Thin underline along the entire bottom edge
  canvas.drawRect(0,height - mBottomBorderThickness,getWidth(),mBottomBorderPaint);

  // Vertical separators between the titles
  int separatorTop = (height - dividerHeightPX) / 2;
  for (int i = 0; i < childCount - 1; i++) {
   View child = getChildAt(i);
   mDividerPaint.setColor(tabColorizer.getDividerColor(i));
   canvas.drawLine(child.getright(),separatorTop,child.getright(),separatorTop + dividerHeightPx,mDividerPaint);
  }
 }

 /**
  * Set the alpha value of the {@code color} to be the given {@code alpha} value.
  */
 private static int setColorAlpha(int color,byte alpha) {
  return Color.argb(alpha,Color.red(color),Color.green(color),Color.blue(color));
 }

 /**
  * Blend {@code color1} and {@code color2} using the given ratio.
  *
  * @param ratio of which to blend. 1.0 will return {@code color1},0.5 will give an even blend,*    0.0 will return {@code color2}.
  */
 private static int blendColors(int color1,int color2,float ratio) {
  final float inverseRation = 1f - ratio;
  float r = (Color.red(color1) * ratio) + (Color.red(color2) * inverseRation);
  float g = (Color.green(color1) * ratio) + (Color.green(color2) * inverseRation);
  float b = (Color.blue(color1) * ratio) + (Color.blue(color2) * inverseRation);
  return Color.rgb((int) r,(int) g,(int) b);
 }

 private static class SimpleTabColorizer implements SlidingTabLayout.TabColorizer {
  privatE int[] mInDicatorColors; //
  privatE int[] mDividerColors;  //


  @Override
  public final int geTinDicatorColor(int position) {
   return mInDicatorColors[position % mInDicatorColors.length];
  }

  @Override
  public final int getDividerColor(int position) {
   return mDividerColors[position % mDividerColors.length];
  }

  void seTinDicatorColors(int... colors) {
   mInDicatorColors = colors;
  }

  void setDividerColors(int... colors) {
   mDividerColors = colors;
  }
 }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="SlidingTabLayout">
  <attr name="android:textColorPriMary" />
  <attr name="textColorTabDefault" format="color" />
  <attr name="textColorTabSELEcted" format="color" />
 </declare-styleable>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://scheR_882_11845@as.android.com/apk/res/android"
 xmlns:tools="http://scheR_882_11845@as.android.com/tools"
 xmlns:app="http://scheR_882_11845@as.android.com/apk/res-auto"
 android:id="@+id/activity_main"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context="com.example.my.slidingtablayout.MainActivity">
 <!-- 在上方就在上面，在下方就在下面（tab栏） -->
 <com.example.my.slidingtablayout.SlidingTabLayout
  android:id="@+id/sliding"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  app:textColorTabDefault="#000000"
  app:textColorTabSELEcted="@color/colOraccent"
  />

 <android.support.v4.view.ViewPager
  android:id="@+id/view_pager"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  />
</LinearLayout>

package com.example.my.slidingtablayout;

import android.graphics.Color;
import android.os.bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
 //创建 颜色数组 用来做viewpager的背景
 @Override
 protected void onCreate(Bundle savedInstanceStatE) {
  super.onCreate(savedInstanceStatE);
  setContentView(R.layout.activity_main);
  ViewPager pager = (ViewPager) findViewById(R.id.view_pager);
  SlidingTabLayout tab = (SlidingTabLayout) findViewById(R.id.sliding);
  tab.setDividerColors(Color.TRANSPARENT); //设置标题的分割线
  tab.setSELEctedInDicatorColors(Color.rgb(51,181,229)); //设置滚动条的颜色
  tab.settitleSize(18); //...设置字体的颜色，默认16

  MyAdapte adapter = new MyAdapte();
  pager.setAdapter(adapter);
  tab.setViewPager(pager);
 }

 int[] colors = {0xFF123456,0xFF654321,0xFF336699};

 class MyAdapte extends PagerAdapter {
  //可以考虑把这个数组添加到集合里面
  String[] titles = {"AA","BB","CC"};


  ArrayList<LinearLayout> layouts = new ArrayList<LinearLayout>();

  MyAdapte() {

   for (int i = 0; i < 3; i++) {
    LinearLayout l = new LinearLayout(MainActivity.this);
    l.setBACkgroundColor(colors[i]);
    l.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT));
    layouts.add(l);
   }

  }

  @Override
  public int getCount() {
   return layouts.size();
  }

  @Override
  public Boolean isViewFromObject(View view,Object o) {
   return view == o;
  }

  @Override
  public Object instantiateItem(ViewGroup container,int position) {
   LinearLayout l = layouts.get(position);
   container.addView(l);
   return l;
  }

  @Override
  public void destroyItem(ViewGroup container,int position,Object object) {
   container.removeView(layouts.get(position));
  }

  @Override
  public CharSequence getPagetitle(int position) {
   //...可以返回集合list.get(position);
   return titles[position];
  }
 }
}