android学习笔记之GridView的使用

　　除了listview会使用适配器外，还有一种就是GridView，listview是单列多行的显示形式，适用于多项目的查看。而GridView是多行多列的显示形式，一般用在查看图片样式的activity中。一个小demo。每一项都是一个图片下面一行文字。

GirdView的一些属性：

android:numColumns="auto_fit" --------列数设置为自动
android:columnWidth="90dp"，----------每列的宽度，也就是Item的宽度
android:stretchMode="columnWidth"------缩放与列宽大小同步
android:verticalSpacing="10dp"----------垂直边距
android:horizontalSpacing="10dp"-------水平边距

这里使用自定义适配器，

GridViewActivity

public class GridViewActivity extends Activity {

    private GridView gridView;
    private GridViewAdapter adapter;
    private List<Map<String,Object>> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_grid_view);
        gridView = (GridView)findViewById(R.id.gridView);
        list = new ArrayList<Map<String, Object>>();
        adapter = new GridViewAdapter(this,getData());
        gridView.setAdapter(adapter);

    }

GridViewAdapter 
在这里有一个比较重要的就是设置gridview的行高，

convertView.setLayoutParams(new GridView.LayoutParams(100, 100));//重点行

但是这个属性android:columnWidth不知道为什么不能起作用。无论设置多少都不变化

 class GridViewAdapter extends BaseAdapter{
        private LayoutInflater mLayoutIntfalter;
        private Context context;
        private List<Map<String,Object>> list;
        public GridViewAdapter(Context context,List<Map<String,Object>> list){
            this.context = context;
            this.list = list;
            this.mLayoutIntfalter = LayoutInflater.from(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) {

            ViewHold viewHold=null;
            if(convertView == null){
                viewHold = new ViewHold();
                convertView = mLayoutIntfalter.inflate(R.layout.gridviewitemlayout,null);
                viewHold.image =(ImageView)convertView.findViewById(R.id.imageView2);
                viewHold.textView = (TextView)convertView.findViewById(R.id.textView4);
                convertView.setTag(viewHold);
            }else{
                viewHold =(ViewHold) convertView.getTag();
            }
            int id = Integer.parseInt(list.get(position).get("pic").toString());
            viewHold.image.setImageResource(id);
            viewHold.textView.setText(list.get(position).get("titel").toString());
            convertView.setLayoutParams(new GridView.LayoutParams(100, 100));//重点行
            return convertView;
        }
        public final class ViewHold{
            public ImageView image;
            public TextView textView;
        }

gridviewitemlayout.xml

每一项的布局

<?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:orientation="vertical">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageView2" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/textView4" />
</LinearLayout>