一起学Android之GridView

时间:2023-03-09 05:05:05
一起学Android之GridView

本文以一个简单的小例子,简述Android开发中GridView的常见应用,仅供学习分享使用。

概述

GiridView是一个表格显示资源的控件,可以在两个可滚动的方向上显示。列表项的资源会通过ListAdapter自动添加到布局控件中GirdView上。

如下图所示:

一起学Android之GridView

数据绑定步骤

如下图所示:

一起学Android之GridView

涉及知识点

  • android:numColumns="auto_fit"  设置GridView中的列数,可以是数字,auto_fit表示系统自动根据屏幕的大小进行适应性显示。
  • android:verticalSpacing="10dp” 用于设置行与行之间的垂直间隔
  • android:horizontalSpacing="10dp" 用于设置列与列之间的水平间隔
  • android:stretchMode="columnWidth" 设置列中元素的拉伸模式
  • setOnItemClickListener 设置列元素的监听事件

示例效果图

如下图所示:

一起学Android之GridView

核心代码

GridView如下:

 <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.hex.demogridview.MainActivity">
<GridView
android:id="@+id/gv_info"
android:columnWidth="90dp"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:numColumns="auto_fit"
android:stretchMode="columnWidth"
android:layout_width="match_parent"
android:layout_height="match_parent"></GridView>
</RelativeLayout>

列表项代码(图片和文本)

 <?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:id="@+id/img_info"
android:src="@drawable/a011"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/tv_info"
android:text="abc"
android:textSize="20sp"
android:textAlignment="center"
android:textColor="@color/colorAccent"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>

后台代码(Adapter类)

 class  MyAdapter extends BaseAdapter {
private Context mContext; public MyAdapter(Context context) {
this.mContext = context;
} @Override
public int getCount() {
return mList != null ? mList.size() : 0;
} @Override
public Object getItem(int position) {
return mList.get(position);
} @Override
public long getItemId(int position) {
return position;
} @Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (convertView == null) {
// if it's not recycled, initialize some attributes
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); //getLayoutInflater();
convertView = inflater.inflate(R.layout.grid_item,null);
viewHolder=new ViewHolder();
viewHolder.img = (ImageView) convertView.findViewById(R.id.img_info);
viewHolder.tv = (TextView) convertView.findViewById(R.id.tv_info); convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.img.setImageResource((int)mList.get(position).get("img"));
viewHolder.tv.setText((String) mList.get(position).get("txt"));
return convertView;
}
}

后台代码(Activity)

 public class MainActivity extends AppCompatActivity {
private int[] imgs;
private List<Map<String,Object>> mList;
private GridView gvInfo;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gvInfo= (GridView) this.findViewById(R.id.gv_info); imgs=new int[]{R.drawable.a011,R.drawable.a012,R.drawable.a013,R.drawable.a014,R.drawable.a015,R.drawable.a016,
R.drawable.a017,R.drawable.a018,R.drawable.a019,R.drawable.a0110,R.drawable.a0111};
mList=new ArrayList<Map<String, Object>>();
for(int i=0;i<11;i++) {
Map<String, Object> map = new HashMap<String, Object>();
map.put("img", imgs[i]);
map.put("txt", "第" + i + "个");
mList.add(map);
}
MyAdapter adapter =new MyAdapter(this);
gvInfo.setAdapter(adapter);
gvInfo.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
TextView textView= (TextView) view.findViewById(R.id.tv_info);
String msg = textView.getText().toString();
Toast.makeText(MainActivity.this,msg,Toast.LENGTH_SHORT).show();
}
}); }

备注

学习一门新的语言,坚持的源头是兴趣,坚持的前方是希望。