Android：GridView（网格视图）的功能和用法

带预览的图片浏览器

<?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:orientation="vertical"
    tools:context=".MainActivity">
    <GridView
        android:id="@+id/grid01"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:horizontalSpacing="1pt"
        android:verticalSpacing="1pt"
        android:numColumns="4"
        android:gravity="center"
        />
    <ImageView
        android:id="@+id/imageView"
        android:layout_width="240dp"
        android:layout_height="240dp"
        android:layout_gravity="center_horizontal"
        />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/image1"
    android:layout_width="300px"
    android:layout_height="300px"
    android:scaleType="fitCenter" />

package com.example.myapplication;

import android.app.Activity;
import android.os.Bundle;
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 Activity {
    GridView grid;
    ImageView imageView;
    int[] imageIds = new int[]{
            R.drawable.qq, R.drawable.qq, R.drawable.qq, R.drawable.qq,
            R.drawable.qq, R.drawable.qq, R.drawable.qq, R.drawable.qq,
            R.drawable.qq, R.drawable.qq, R.drawable.qq, R.drawable.qq,
    };

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        List<Map<String,Object>> listItems = new ArrayList<Map<String,Object>>();
        for(int i=0;i<imageIds.length;i++){
            Map<String,Object> listItem = new HashMap<String,Object>();
            listItem.put("image",imageIds[i]);
            listItems.add(listItem);
        }
        imageView =(ImageView) findViewById(R.id.imageView);
        SimpleAdapter simpleAdapter = new SimpleAdapter(this,listItems,R.layout.simple_item,new String[]{"image"},new int[]{R.id.image1});
        grid = findViewById(R.id.grid01);
        grid.setAdapter(simpleAdapter);
        grid.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                imageView.setImageResource(imageIds[position]);
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });
        grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                imageView.setImageResource(imageIds[position]);
            }
        });
    }
}

可展开的列表组件（ExpandableListView）

package com.example.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.SimpleAdapter;
import android.widget.TextView;

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

public class MainActivity extends Activity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ExpandableListAdapter adapter = new BaseExpandableListAdapter() {
            int[] logos =new  int[]{
                R.drawable.qq,
                R.drawable.qq,
                R.drawable.qq
            };
            private String[] armTypes = new String[]{"神族兵种","虫族兵种","人族兵种"};
            private String[][] arms = new String[][]{
                    {"狂战士","龙骑士","黑暗圣堂","电兵"},
                    {"小狗","刺蛇","飞龙","自爆飞机"},
                    {"机枪兵","护士MM","幽灵"}
            };
            public int getGroupCount() {
                return armTypes.length;
            }

            @Override
            public int getChildrenCount(int groupPosition) {
                return arms[groupPosition].length;
            }

            @Override
            public Object getGroup(int groupPosition) {
                return  armTypes[groupPosition];
            }

            @Override
            public Object getChild(int groupPosition, int childPosition) {
                return arms[groupPosition][childPosition];
            }

            @Override
            public long getGroupId(int groupPosition) {
                return groupPosition;
            }

            @Override
            public long getChildId(int groupPosition, int childPosition) {
                return childPosition;
            }

            @Override
            public boolean hasStableIds() {
                return true;
            }

            @Override
            public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
                LinearLayout l1 = new LinearLayout(MainActivity.this);
                l1.setOrientation(0);
                ImageView logo = new ImageView(MainActivity.this);
                logo.setImageResource(logos[groupPosition]);

                l1.addView(logo);
                TextView textView = getTextView();
                textView.setText(getGroup(groupPosition).toString());
                l1.addView(textView);
                return l1;
            }

            @Override
            public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
                TextView textView =getTextView();
                textView.setText(getChild(groupPosition,childPosition).toString());
                return textView;
            }

            @Override
            public boolean isChildSelectable(int groupPosition, int childPosition) {
                return true;
            }
            public TextView getTextView(){
                AbsListView.LayoutParams lp=new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,64);
                TextView textView = new TextView(MainActivity.this);
                textView.setLayoutParams(lp);
                textView.setGravity(Gravity.CENTER_VERTICAL|Gravity.LEFT);
                textView.setPadding(36,0,0,0);
                textView.setTextSize(20);
                return textView;
            }
        };
        ExpandableListView expandableListView =findViewById(R.id.list);
        expandableListView.setAdapter(adapter);
    }
}

<?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:orientation="vertical"
    tools:context=".MainActivity">
    <ExpandableListView
        android:id="@+id/list"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
</LinearLayout>

让用户选择

package com.example.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class MainActivity extends Activity {
    Spinner spinner;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        spinner = findViewById(R.id.spinner);
        String[] arr = {"孙悟空", "猪八戒", "唐僧"};
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_multiple_choice, arr);
        spinner.setAdapter(adapter);
    }
}

<?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:orientation="vertical"
    tools:context=".MainActivity">
    <Spinner
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:entries="@array/books"
        />
    <Spinner
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/spinner"
        />
</LinearLayout>