实现水平滑动，并且动态添加数据

需求就是实现如果所示的，水平滑动，但是item个数不确定。

一开始遇到，就把item独立出来，用HorizontalScrollView去实现水平滑动，在里面的子LinearLayout里面去动态的添加item内容，这样可以实现，不过不好控制，不是特别方便，后来在网上找到了下面这个方法：

用HorizontalScrollView实现水平滑动，在里面的子LinearLayout里面嵌套了GridView来实现动态的添加数据

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <HorizontalScrollView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dp" >

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="fill_parent"
            android:layout_margin="10dp" >

            <GridView
                android:id="@+id/grid"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:gravity="center"
                android:numColumns="auto_fit"
                android:stretchMode="spacingWidthUniform" >
            </GridView>
        </LinearLayout>
    </HorizontalScrollView>

</LinearLayout>

重点在于setGridView方法里面的代码

public class MainActivity extends Activity {

    List<CityItem> cityList;
    RelativeLayout itmel;
    GridView gridView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//        LayoutInflater layoutInflater = getLayoutInflater();
        gridView = (GridView) findViewById(R.id.grid);
        setData();
        setGridView();
    }

    private void setData() {
        cityList = new ArrayList<CityItem>();
        CityItem item = new CityItem();
        item.setCityName("深圳");
        item.setCityCode("0755");
        cityList.add(item);
        item = new CityItem();
        item.setCityName("上海");
        item.setCityCode("021");
        cityList.add(item);
        item = new CityItem();
        item.setCityName("广州");
        item.setCityCode("020");
        cityList.add(item);
        item = new CityItem();
        item.setCityName("北京");
        item.setCityCode("010");
        cityList.add(item);
        item = new CityItem();
        item.setCityName("武汉");
        item.setCityCode("027");
        cityList.add(item);
        item = new CityItem();
        item.setCityName("孝感");
        item.setCityCode("0712");
        cityList.add(item);
        cityList.addAll(cityList);
    }

    private void setGridView() {

        int size = cityList.size();

        int length = 100;

        DisplayMetrics dm = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(dm);
        float density = dm.density;
        int gridviewWidth = (int) (size * (length + 4) * density);
        int itemWidth = (int) (length * density);

        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
                gridviewWidth, LinearLayout.LayoutParams.MATCH_PARENT);
        gridView.setLayoutParams(params); // 重点
        gridView.setColumnWidth(itemWidth); // 重点
        gridView.setHorizontalSpacing(5); // 间距
        gridView.setStretchMode(GridView.NO_STRETCH);
        gridView.setNumColumns(size); // 重点

        MyTopicGridViewAdapter adapter = new MyTopicGridViewAdapter(getApplicationContext(),
                cityList);
        gridView.setAdapter(adapter);
    }
}

剩余的就是item布局、item对象、adapter

item布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/itemlayout"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/ItemImage"
        android:layout_width="80.0dip"
        android:layout_height="80.0dip"
        android:layout_gravity="center_horizontal"
        android:src="@drawable/china" >
    </ImageView>

    <TextView
        android:id="@+id/tvCity"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="Title"
        android:textColor="#000000" >
    </TextView>

    <TextView
        android:id="@+id/tvCode"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="Info"
        android:textColor="#000000" >
    </TextView>

</LinearLayout>

item对象：

public class CityItem {
    private String cityName;
    private String cityCode;

    public String getCityName() {
        return cityName;
    }

    public void setCityName(String cityName) {
        this.cityName = cityName;
    }

    public String getCityCode() {
        return cityCode;
    }

    public void setCityCode(String cityCode) {
        this.cityCode = cityCode;
    }
}

adapter

public class MyTopicGridViewAdapter extends BaseAdapter {
    Context context;
    List<CityItem> list;

    public MyTopicGridViewAdapter(Context _context, List<CityItem> _list) {
        this.list = _list;
        this.context = _context;
    }

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

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater layoutInflater = LayoutInflater.from(context);
        convertView = layoutInflater.inflate(R.layout.list_item, null);
        TextView tvCity = (TextView) convertView.findViewById(R.id.tvCity);
        TextView tvCode = (TextView) convertView.findViewById(R.id.tvCode);
        CityItem city = list.get(position);

        tvCity.setText(city.getCityName());
        tvCode.setText(city.getCityCode());
        return convertView;
    }
}