GridView

(一）

知识点：

(1)numColumns设置列数

(2)SetOnItemClicker设置监听

1.效果图：点击小图像，图像在下边变大

2.activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.app2.MainActivity"
    android:orientation="vertical">

    <GridView
        android:id="@+id/gv"
        android:numColumns="4"
        android:verticalSpacing="4dp"
        android:horizontalSpacing="4dp"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
    </GridView>

    <ImageView
        android:id="@+id/iv"
        android:layout_width="150dp"
        android:layout_height="150dp" />
</LinearLayout>

2.item.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">
    <ImageView
        android:id="@+id/item_iv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

3.MianActivity.java

package com.example.app2;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.SimpleAdapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {
    private GridView gridView;
    private ImageView imageView;
    private List list;
    private int[] pics={R.drawable.e1,
            R.drawable.e2,
            R.drawable.e3,
            R.drawable.e4,
            R.drawable.e5,
            R.drawable.e6,
            R.drawable.e7,
            R.drawable.e8,
    };
    private Map<String,Object> map;
    private SimpleAdapter simpleAdapter;
    private String[] pic_key={"pic"};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        gridView = (GridView)findViewById(R.id.gv);
        imageView=(ImageView)findViewById(R.id.iv);

        //新建数据源
        list = new ArrayList();
        for (int i=0;i<pics.length;i++){
            map=new HashMap<>();
            map.put("pic",pics[i]);
            list.add(map);
        }

        //数据绑定适配器
        simpleAdapter = new SimpleAdapter(MainActivity.this,list,R.layout.item,pic_key,new int[]{R.id.item_iv});

        //视图加载适配器
        gridView.setAdapter(simpleAdapter);

        //gridView绑定监听
        gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                imageView.setImageResource(pics[position]);
            }
        });
    }
}