详解Android使GridView横向水平滚动的实现方式

  public static List<ResolveInfo> getAppData(Context context) {
    PackageManager packageManager = context.getPackageManager();
    Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
    mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
    return packageManager.queryIntentActivities(mainIntent, 0);
  }

  /**
   * 将GridView改成单行横向布局
   */
  private void changeGridView() {
    // item宽度
    int itemWidth = DensityUtil.dip2px(this, 100);
    // item之间的间隔
    int itemPaddingH = DensityUtil.dip2px(this, 1);
    int size = datas.size();
    // 计算GridView宽度
    int gridviewWidth = size * (itemWidth + itemPaddingH);

    LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
        gridviewWidth, LinearLayout.LayoutParams.MATCH_PARENT);
    mContentGv.setLayoutParams(params);
    mContentGv.setColumnWidth(itemWidth);
    mContentGv.setHorizontalSpacing(itemPaddingH);
    mContentGv.setStretchMode(GridView.NO_STRETCH);
    mContentGv.setNumColumns(size);
  }

  /**
   * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
   * @param context  上下文
   * @param dpValue  dp值
   * @return px值
   */
  public static int dip2px(Context context, float dpValue) {
    final float scale = context.getResources().getDisplayMetrics().density;
    return (int) (dpValue * scale + 0.5f);
  }

  <HorizontalScrollView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:scrollbars="none">
    <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="match_parent">
      <GridView
        android:id="@+id/gv_horizontal_gridview_line"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="none"/>
    </LinearLayout>
  </HorizontalScrollView>

  /**
   * 获取系统所有的应用程序，根据每页需要显示的item数量，生成相应数量的GridView页面
   */
  private void initViews(List<ResolveInfo> datas) {
    int dataSize = datas.size();

    // （需要页数 = 总数量 ÷ 每页显示数量）向上取整数
    int PageCount = (int) Math.ceil(dataSize / APP_SIZE);
    mGridViewList = new ArrayList<>();
    for (int i = 0; i <= PageCount; i++) {
      GridView appPage = new GridView(this);
      appPage.setAdapter(new HorizontalGvAdapter(this, datas, i));
      appPage.setNumColumns(4);
      appPage.setVerticalSpacing(1);
      appPage.setHorizontalSpacing(1);
      appPage.setHorizontalScrollBarEnabled(false);
      appPage.setVerticalScrollBarEnabled(false);
      mGridViewList.add(appPage);
    }

    if(dataSize % APP_SIZE == 0){
      mGridViewList.remove(mGridViewList.size()-1);
      PageCount--;
    }

    mGvPagerAdapter = new HorizontalGvPagerAdapter(mGridViewList);
    viewPager.setAdapter(mGvPagerAdapter);
    viewPager.addOnPageChangeListener(new MyPageChangeListener());

    addDot(PageCount);
  }

    if(dataSize % APP_SIZE == 0){
      mGridViewList.remove(mGridViewList.size()-1);
      PageCount--;
    }

  /**
   * 所有应用数据
   */
  private List<ResolveInfo> mAppDatas = new ArrayList<ResolveInfo>();

  public HorizontalGvAdapter(Context context, List<ResolveInfo> list, int page) {
    this.mContext = context;

    // 开始加载的位置
    int pageStart = page * HorizontalGridViewAct.APP_SIZE;
    // 结束加载的位置
    int pageEnd = pageStart + HorizontalGridViewAct.APP_SIZE;

    while ((pageStart < list.size()) && (pageStart < pageEnd)) {
      mAppDatas.add(list.get(pageStart));
      pageStart++;
    }
  }

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:background="#ffffff"
       android:orientation="vertical">
  <android.support.v4.view.ViewPager
    android:id="@+id/vp_horizontal_gridview"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:layout_gravity="center"
    android:background="#c5c5c5"
    android:scaleType="fitXY"/>

  <!-- 底部小圆点 -->
  <LinearLayout
    android:id="@+id/ll_dot_container"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="#4b4b4b"
    android:layout_gravity="bottom"
    android:gravity="center"
    android:orientation="horizontal"/>
</LinearLayout>

  // 放圆点的list
  private List<View> dotViewsList;

  /**
   * 创建指定数量的圆点
   * @param dotNumber viewPager的数量
   */
  private void addDot(int dotNumber) {
    if (null == dotViewsList) {
      dotViewsList = new ArrayList<View>();
    }
    LinearLayout dotLayout = (LinearLayout) findViewById(R.id.ll_dot_container);
    for (int i = 0; i <= dotNumber; i++) {
      ImageView dotView = new ImageView(this);
      LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
          FrameLayout.LayoutParams.WRAP_CONTENT,
          FrameLayout.LayoutParams.WRAP_CONTENT);

      // 圆点与圆点之间的距离
      params.leftMargin = 10;
      params.rightMargin = 10;

      // 圆点的大小
      params.height = 15;
      params.width = 15;

      dotLayout.addView(dotView, params);
      dotViewsList.add(dotView);
    }
    // 设置圆点默认选中第一个
    setDotShow(0);
  }
动态添加完小圆点后，就可以设置它们的选中状态了，这里只需要更改对应小圆点的图片显示就行

  /**
   * 显示底部圆点导航
   * @param position 选中哪个圆点
   */
  private void setDotShow(int position){
    if (dotViewsList == null){
      return;
    }
    for (int i = 0; i < dotViewsList.size(); i++) {
      if (i == position) {
        dotViewsList.get(position).setBackgroundResource(R.drawable.ic_dot_on);
      } else {
        dotViewsList.get(i).setBackgroundResource(R.drawable.ic_dot_off);
      }
    }
  }