一手遮天 Android - view（集合类）: GridView 基础 2
示例如下:
/view/collection/GridViewDemo2.java
/**
* GridView - 网格控件
*
* 本例演示
* 1、GridView 通过 BaseAdapter 显示数据
* 2、GridView 的常用属性的说明（参见 xml 中的说明）
* 3、其他更多知识点请参见 ListView 的说明（GridView 和 ListView 都继承自 AbsListView）
*/
package com.webabcd.androiddemo.view.collection;
import android.content.Context;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import com.webabcd.androiddemo.R;
import java.util.ArrayList;
import java.util.List;
public class GridViewDemo2 extends AppCompatActivity {
private Button mButton1;
private Button mButton2;
private Button mButton3;
private Button mButton4;
private GridView mGridView1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_collection_gridviewdemo2);
mGridView1 = findViewById(R.id.gridView1);
mButton1 = findViewById(R.id.button1);
mButton2 = findViewById(R.id.button2);
mButton3 = findViewById(R.id.button3);
mButton4 = findViewById(R.id.button4);
sample();
}
private void sample() {
// 构造数据
List<MyData> myDataList = new ArrayList<MyData>();
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
myDataList.add(new MyData(R.drawable.img_sample_son));
// 实例化自定义的 BaseAdapter
MyAdapter myAdapter = new MyAdapter(myDataList, this);
mGridView1.setAdapter(myAdapter);
// 设置 stretchMode 属性
mButton1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 相当于 xml 中的 stretchMode="none"
mGridView1.setStretchMode(GridView.NO_STRETCH);
}
});
mButton2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 相当于 xml 中的 stretchMode="spacingWidth"
mGridView1.setStretchMode(GridView.STRETCH_SPACING);
}
});
mButton3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 相当于 xml 中的 stretchMode="columnWidth"
mGridView1.setStretchMode(GridView.STRETCH_COLUMN_WIDTH);
}
});
mButton4.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 相当于 xml 中的 stretchMode="spacingWidthUniform"
mGridView1.setStretchMode(GridView.STRETCH_SPACING_UNIFORM);
}
});
}
// 自定义实体类
class MyData {
private int _logoId;
public MyData() {
}
public MyData(int logoId) {
this._logoId = logoId;
}
public int getLogoId() {
return _logoId;
}
public void setLogoId(int logoId) {
this._logoId = logoId;
}
}
// 自定义 BaseAdapter
class MyAdapter extends BaseAdapter {
private List<MyData> _myDataList;
private Context _context;
public MyAdapter(List<MyData> myDataList, Context context) {
this._myDataList = myDataList;
this._context = context;
}
// 需要呈现的 item 的总数
@Override
public int getCount() {
return _myDataList.size();
}
// 返回指定索引位置的 item 的对象
@Override
public Object getItem(int position) {
return _myDataList.get(position);
}
// 返回指定索引位置的 item 的 id
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
convertView = LayoutInflater.from(_context).inflate(R.layout.item_view_collection_gridviewdemo2, parent, false);
holder = new ViewHolder();
holder.imgLogo = (ImageView) convertView.findViewById(R.id.imgLogo);
convertView.setTag(holder); // 将 holder 保存到 convertView 中
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.imgLogo.setBackgroundResource(_myDataList.get(position).getLogoId());
return convertView;
}
class ViewHolder {
ImageView imgLogo;
}
}
}
/layout/activity_view_collection_gridviewdemo2.xml
<?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">
<!--
horizontalSpacing - 水平方向单元格之间的间距
verticalSpacing - 垂直方向单元格之间的间距
gravity - 单元格内元素相对于单元格的对齐方式
numColumns - 当此值指定为一个大于 0 的整数时
指定网格控件的列数（网格列宽会平均分，行高和行数会自适应）
numColumns - 当此值指定为 auto_fit 时（auto_fit 就是 -1）
1、列数会自适应，列宽会参考 columnWidth 值，行高和行数会自适应
2、stretchMode - 列的拉伸方式
none - 不拉伸，列的宽度就是 columnWidth 值
spacingWidth - 列会填满 GridView 的宽度，列之间的间距会被拉伸，列的宽度就是 columnWidth 值
columnWidth - 列会填满 GridView 的宽度，列本身会被拉伸，即列的宽度会大于等于 columnWidth 值
spacingWidthUniform - 列会填满 GridView 的宽度，列本身和列之间的间距都 会被拉伸
-->
<GridView
android:id="@+id/gridView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:horizontalSpacing="5dp"
android:verticalSpacing="5dp"
android:gravity="center"
android:numColumns="auto_fit"
android:columnWidth="60dp"
android:stretchMode="none"/>
<!--
以下几个按钮用于动态修改 GridView 的 stretchMode 属性，以便观察效果
-->
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="stretchMode:none"/>
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="stretchMode:spacingWidth"/>
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="stretchMode:columnWidth"/>
<Button
android:id="@+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="stretchMode:spacingWidthUniform"/>
</LinearLayout>
/layout/item_view_collection_gridviewdemo2.xml
<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/imgLogo"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY">
</ImageView>