Android仿今日头条顶部导航栏效果的实例代码

package com.rainsong.toutiaotabdemo; 
import java.util.ArrayList; 
import java.util.List; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentPagerAdapter; 
import android.support.v4.view.ViewPager; 
public class MainActivity extends FragmentActivity { 
 private CategoryTabStrip tabs; 
 private ViewPager pager; 
 private MyPagerAdapter adapter; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 tabs = (CategoryTabStrip) findViewById(R.id.category_strip); 
 pager = (ViewPager) findViewById(R.id.view_pager); 
 adapter = new MyPagerAdapter(getSupportFragmentManager()); 
 pager.setAdapter(adapter); 
 tabs.setViewPager(pager); 
 } 
 public class MyPagerAdapter extends FragmentPagerAdapter { 
 private final List catalogs = new ArrayList(); 
 public MyPagerAdapter(FragmentManager fm) { 
 super(fm); 
 catalogs.add(getString(R.string.category_hot)); 
 catalogs.add("u672cu5730"); 
 catalogs.add(getString(R.string.category_video)); 
 catalogs.add(getString(R.string.category_society)); 
 catalogs.add(getString(R.string.category_entertainment)); 
 catalogs.add(getString(R.string.category_tech)); 
 catalogs.add(getString(R.string.category_finance)); 
 catalogs.add(getString(R.string.category_military)); 
 catalogs.add(getString(R.string.category_world)); 
 catalogs.add(getString(R.string.category_image_ppmm)); 
 catalogs.add(getString(R.string.category_health)); 
 catalogs.add(getString(R.string.category_government)); 
 } 
 @Override 
 public CharSequence getPageTitle(int position) { 
 return catalogs.get(position); 
 } 
 @Override 
 public int getCount() { 
 return catalogs.size(); 
 } 
 @Override 
 public Fragment getItem(int position) { 
 return NewsFragment.newInstance(position); 
 } 
 } 
} 

package com.rainsong.toutiaotabdemo; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Rect; 
import android.graphics.drawable.Drawable; 
import android.support.v4.view.ViewPager; 
import android.support.v4.view.ViewPager.OnPageChangeListener; 
import android.util.AttributeSet; 
import android.util.DisplayMetrics; 
import android.util.TypedValue; 
import android.view.Gravity; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.HorizontalScrollView; 
import android.widget.LinearLayout; 
import android.widget.TextView; 
public class CategoryTabStrip extends HorizontalScrollView { 
 private LayoutInflater mLayoutInflater; 
 private final PageListener pageListener = new PageListener(); 
 private ViewPager pager; 
 private LinearLayout tabsContainer; 
 private int tabCount; 
 private int currentPosition = 0; 
 private float currentPositionOffset = 0f; 
 private Rect indicatorRect; 
 private LinearLayout.LayoutParams defaultTabLayoutParams; 
 private int scrollOffset = 10; 
 private int lastScrollX = 0; 
 private Drawable indicator; 
 private TextDrawable[] drawables; 
 private Drawable left_edge; 
 private Drawable right_edge; 
 public CategoryTabStrip(Context context) { 
 this(context, null); 
 } 
 public CategoryTabStrip(Context context, AttributeSet attrs) { 
 this(context, attrs, 0); 
 } 
 public CategoryTabStrip(Context context, AttributeSet attrs, int defStyle) { 
 super(context, attrs, defStyle); 
 mLayoutInflater = LayoutInflater.from(context); 
 drawables = new TextDrawable[3]; 
 int i = 0; 
 while (i  0f && currentPosition  0 ? Math.max(0, getChildAt(0).getWidth() - getWidth() + getPaddingLeft() + getPaddingRight()) : 0; 
 } 
 // CategoryTabStrip与ViewPager联动逻辑 
 private void scrollToChild(int position, int offset) { 
 if (tabCount == 0) { 
 return; 
 } 
 calculateIndicatorRect(indicatorRect); 
 int newScrollX = lastScrollX; 
 if (indicatorRect.left  getScrollX() + getWidth() - scrollOffset) { 
 newScrollX = indicatorRect.right - getWidth() + scrollOffset; 
 } 
 if (newScrollX != lastScrollX) { 
 lastScrollX = newScrollX; 
 scrollTo(newScrollX, 0); 
 } 
 } 
 // 自定义绘图 
 @Override 
 public void draw(Canvas canvas) { 
 super.draw(canvas); 
 // 绘制高亮背景矩形红框 
 calculateIndicatorRect(indicatorRect); 
 if(indicator != null) { 
 indicator.setBounds(indicatorRect); 
 indicator.draw(canvas); 
 } 
 // 绘制背景红框内标签文本 
 int i = 0; 
 while (i  currentPosition + 1) { 
 i++; 
 } else { 
 ViewGroup tab = (ViewGroup)tabsContainer.getChildAt(i); 
 TextView category_text = (TextView) tab.findViewById(R.id.category_text); 
 if (category_text != null) { 
 TextDrawable textDrawable = drawables[i - currentPosition + 1]; 
 int save = canvas.save(); 
 calculateIndicatorRect(indicatorRect); 
 canvas.clipRect(indicatorRect); 
 textDrawable.setText(category_text.getText()); 
 textDrawable.setTextSize(0, category_text.getTextSize()); 
 textDrawable.setTextColor(getResources().getColor(R.color.category_tab_highlight_text)); 
 int left = tab.getLeft() + category_text.getLeft() + (category_text.getWidth() - textDrawable.getIntrinsicWidth()) / 2 + getPaddingLeft(); 
 int top = tab.getTop() + category_text.getTop() + (category_text.getHeight() - textDrawable.getIntrinsicHeight()) / 2 + getPaddingTop(); 
 textDrawable.setBounds(left, top, textDrawable.getIntrinsicWidth() + left, textDrawable.getIntrinsicHeight() + top); 
 textDrawable.draw(canvas); 
 canvas.restoreToCount(save); 
 } 
 i++; 
 } 
 } 
 // 绘制左右边界阴影效果 
 i = canvas.save(); 
 int top = getScrollX(); 
 int height = getHeight(); 
 int width = getWidth(); 
 canvas.translate((float) top, 0.0f); 
 if (left_edge == null || top = getScrollRange()) { 
 canvas.restoreToCount(i); 
 } 
 right_edge.setBounds(width - right_edge.getIntrinsicWidth(), 0, width, height); 
 right_edge.draw(canvas); 
 canvas.restoreToCount(i); 
 } 
 left_edge.setBounds(0, 0, left_edge.getIntrinsicWidth(), height); 
 left_edge.draw(canvas); 
 if (right_edge == null || top >= getScrollRange()) { 
 canvas.restoreToCount(i); 
 } 
 right_edge.setBounds(width - right_edge.getIntrinsicWidth(), 0, width, height); 
 right_edge.draw(canvas); 
 canvas.restoreToCount(i); 
 } 
 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(); 
 } 
 @Override 
 public void onPageScrollStateChanged(int state) { 
 if (state == ViewPager.SCROLL_STATE_IDLE) { 
 if(pager.getCurrentItem() == 0) { 
 // 滑动到最左边 
 scrollTo(0, 0); 
 } else if (pager.getCurrentItem() == tabCount - 1) { 
 // 滑动到最右边 
 scrollTo(getScrollRange(), 0); 
 } else { 
 scrollToChild(pager.getCurrentItem(), 0); 
 } 
 } 
 } 
 @Override 
 public void onPageSelected(int position) { 
 } 
 } 
}