Android仿今日头条滑动页面导航效果

<span style="font-size:14px;"><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:app="http://schemas.android.com/apk/res/com.hankkin.PagerSlidingTabStrip"     android:orientation="vertical"     android:layout_width="fill_parent"     android:layout_height="fill_parent"   >   <com.hankkin.PagerSlidingTabStrip.view.PagerSlidingTabStrip    android:id="@+id/tab"    app:pstsShouldExpand="false"    app:pstsUnderlineHeight="2dp"    app:pstsIndicatorHeight="2dp"    app:pstsIndicatorColor="@android:color/holo_blue_light"    app:selectedTabTextColor="@android:color/holo_blue_light"    app:pstsDividerColor="@android:color/transparent"    app:pstsTabBackground="@drawable/background"    android:background="@android:color/white"    android:layout_width="match_parent"    android:layout_height="55dp"/>   <android.support.v4.view.ViewPager    android:id="@+id/pager"    android:layout_width="match_parent"    android:layout_height="match_parent"/>  </LinearLayout></span><span style="font-size:18px;"> </span> 

<span style="font-size:14px;">package com.hankkin.PagerSlidingTabStrip.adapter;  import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import com.hankkin.PagerSlidingTabStrip.fragment.AndroidFragment; import com.hankkin.PagerSlidingTabStrip.fragment.JavaFragment; import com.hankkin.PagerSlidingTabStrip.fragment.ObjectCFragment;  import java.util.List;  public class MyAdapter extends FragmentPagerAdapter {  private AndroidFragment androidFragment;  private JavaFragment javaFragment;  private ObjectCFragment objectCFragment;  private String[] titles;  public MyAdapter(FragmentManager fm,String[] titles) {   super(fm);   this.titles = titles;  }   @Override  public Fragment getItem(int position) {   switch (position) {    case 0:     if (androidFragment == null) {      androidFragment = new AndroidFragment();     }     return androidFragment;    case 1:     if (javaFragment == null) {      javaFragment = new JavaFragment();     }     return javaFragment;    case 2:     if (objectCFragment == null) {      objectCFragment = new ObjectCFragment();     }     return objectCFragment;    default:     return null;   }  }   @Override  public int getCount() {   return titles.length;  }   public String getPageTitle(int i){   return titles[i];  }  } </span> 

<span style="font-size:14px;"> private void initViews(){   fragments = new ArrayList<>();   pagerTab = (PagerSlidingTabStrip) findViewById(R.id.tab);   pager = (ViewPager) findViewById(R.id.pager);    for (int i=0;i<titles.length;i++){    Fragment fragment = new Fragment();    fragments.add(fragment);   }    adapter = new MyAdapter(getSupportFragmentManager(),titles);   pager.setAdapter(adapter);   pagerTab.setViewPager(pager);  }</span> 

private int indicatorColor = 0xFF666666;// 滑动指示器颜色 private int underlineColor = 0x1A000000;//在视图的底部的全宽度的线pstsunderlinecolor颜色 private int dividerColor = 0x1A000000;//选项卡之间的分隔pstsdividercolor颜色  private boolean shouldExpand = false;//pstsshouldexpand如果设置为TRUE，每个标签都给予同样的重量，默认为false private boolean textAllCaps = true;//pststextallcaps如果为真，所有选项卡标题都是大写，默认为true  private int scrollOffset = 52;//pstsscrolloffset卷轴被选择的标签的偏移 private int indicatorHeight = 8;//滑动指示器pstsindicatorheight private int underlineHeight = 2;//在视图的底部的全宽度的线pstsunderlineheight高度 private int dividerPadding = 12;//pstsdividerpadding顶部和底部填充的分频器 private int tabPadding = 24;//pststabpaddingleftright左、右填充每个选项卡 private int dividerWidth = 1;//选项卡分割线宽度  private int tabTextSize = 12;//选项卡字体大小 private int tabTextColor = 0xFF666666;//选项卡字体颜色 private int selectedTabTextColor = 0xFF666666;//当前选中字体颜色 private Typeface tabTypeface = null; private int tabTypefaceStyle = Typeface.NORMAL;  private int lastScrollX = 0;  private int tabBackgroundResId = R.drawable.background;//pststabbackground背景绘制的每个标签，应该是一个statelistdrawable 

<span style="font-size:14px;">public PagerSlidingTabStrip(Context context, AttributeSet attrs, int defStyle) {   super(context, attrs, defStyle);    setFillViewport(true);//默认使子view可以拉伸来填满整个屏幕   setWillNotDraw(false);//默认不执行OnDraw()方法   //初始化盛放按钮标题的线性布局   tabsContainer = new LinearLayout(context);   tabsContainer.setOrientation(LinearLayout.HORIZONTAL);   tabsContainer.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));   addView(tabsContainer);    DisplayMetrics dm = getResources().getDisplayMetrics();   //导入相应资源文件   scrollOffset = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, scrollOffset, dm);   indicatorHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, indicatorHeight, dm);   underlineHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, underlineHeight, dm);   dividerPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dividerPadding, dm);   tabPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, tabPadding, dm);   dividerWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dividerWidth, dm);   tabTextSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm);    // get system attrs (android:textSize and android:textColor)    TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);    tabTextSize = a.getDimensionPixelSize(0, tabTextSize);   tabTextColor = a.getColor(1, tabTextColor);    a.recycle();    // get custom attrs    a = context.obtainStyledAttributes(attrs, R.styleable.PagerSlidingTabStrip);    indicatorColor = a.getColor(R.styleable.PagerSlidingTabStrip_pstsIndicatorColor, indicatorColor);    //tab文字选中时的颜色,默认和滑动指示器的颜色一致   selectedTabTextColor=a.getColor(R.styleable.PagerSlidingTabStrip_selectedTabTextColor, indicatorColor);   //初始化属性样式   underlineColor = a.getColor(R.styleable.PagerSlidingTabStrip_pstsUnderlineColor, underlineColor);   dividerColor = a.getColor(R.styleable.PagerSlidingTabStrip_pstsDividerColor, dividerColor);   indicatorHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsIndicatorHeight, indicatorHeight);   underlineHeight = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsUnderlineHeight, underlineHeight);   dividerPadding = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsDividerPadding, dividerPadding);   tabPadding = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsTabPaddingLeftRight, tabPadding);   tabBackgroundResId = a.getResourceId(R.styleable.PagerSlidingTabStrip_pstsTabBackground, tabBackgroundResId);   shouldExpand = a.getBoolean(R.styleable.PagerSlidingTabStrip_pstsShouldExpand, shouldExpand);   scrollOffset = a.getDimensionPixelSize(R.styleable.PagerSlidingTabStrip_pstsScrollOffset, scrollOffset);   textAllCaps = a.getBoolean(R.styleable.PagerSlidingTabStrip_pstsTextAllCaps, textAllCaps);    a.recycle();    rectPaint = new Paint();   rectPaint.setAntiAlias(true);   rectPaint.setStyle(Style.FILL);    dividerPaint = new Paint();   dividerPaint.setAntiAlias(true);   dividerPaint.setStrokeWidth(dividerWidth);    defaultTabLayoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);   expandedTabLayoutParams = new LinearLayout.LayoutParams(0, LayoutParams.MATCH_PARENT, 1.0f);    if (locale == null) {    locale = getResources().getConfiguration().locale;   }  }</span> 

<span style="font-size:14px;">private class PageListener implements OnPageChangeListener {    @Override   public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {    currentPosition = position;    currentPositionOffset = positionOffset;     scrollToChild(position, (int) (positionOffset * tabsContainer.getChildAt(position).getWidth()));     invalidate();     if (delegatePageListener != null) {     delegatePageListener.onPageScrolled(position, positionOffset, positionOffsetPixels);    }   }    @Override   public void onPageScrollStateChanged(int state) {    if (state == ViewPager.SCROLL_STATE_IDLE) {     scrollToChild(pager.getCurrentItem(), 0);    }     if (delegatePageListener != null) {     delegatePageListener.onPageScrollStateChanged(state);    }   }    @Override   public void onPageSelected(int position) {    selectedPosition = position;    updateTabStyles();    if (delegatePageListener != null) {     delegatePageListener.onPageSelected(position);    }   }   }</span> 

<span style="font-size:14px;">private void updateTabStyles() {    for (int i = 0; i < tabCount; i++) {     View v = tabsContainer.getChildAt(i);     v.setBackgroundResource(tabBackgroundResId);     if (v instanceof TextView) {      TextView tab = (TextView) v;     tab.setTextSize(TypedValue.COMPLEX_UNIT_PX, tabTextSize);     tab.setTypeface(tabTypeface, tabTypefaceStyle);     tab.setTextColor(tabTextColor);      // setAllCaps() is only available from API 14, so the upper case is made manually if we are on a     // pre-ICS-build     if (textAllCaps) {      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {       tab.setAllCaps(true);      } else {       tab.setText(tab.getText().toString().toUpperCase(locale));      }     }     if (i == selectedPosition) {      tab.setTextColor(selectedTabTextColor);     }    }   }   }</span>