Android开发学习笔记 Gallery和GridView浅析
时间：2021-07-27 08:19:52 | 栏目：Android代码 | 点击：次
一.Gallery的简介
Gallery（画廊）是一个锁定中心条目并且拥有水平滚动列表的视图，一般用来浏览图片，并且可以响应事件显示信息。Gallery还可以和ImageSwitcher组件结合使用来实现一个通过缩略图来浏览图片的效果。
Gallery常用的XML属性
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属性名称
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描述
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android:animationDuration
|
设置布局变化时动画的转换所需的时间（毫秒级）。仅在动画开始时计时。该值必须是整数，比如：100。
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android:gravity
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指定在对象的X和Y轴上如何放置内容。指定一下常量中的一个或多个（使用 “|”分割）
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android:spacing
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图片之间的间距
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android:unselectedAlpha
|
设置未选中的条目的透明度(Alpha)。该值必须是float类型，比如：“1.2”。
|
首先介绍Gallery单独使用的例子：
MainActivity.java
package com.android.gallerydemo;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity {
private Gallery gallery;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
gallery = (Gallery)findViewById(R.id.gallery);
//设置图片适配器
gallery.setAdapter(new ImageAdapter(this));
//设置监听器
gallery.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?>parent, View v, int position, long id) {
Toast.makeText(MainActivity.this, "点击了第"+(position+1)+"张图片", Toast.LENGTH_LONG).show();
}
});
}
}
class ImageAdapter extends BaseAdapter{
//声明Context
private Context context;
//图片源数组
private Integer[] imageInteger={
R.drawable.pic1,
R.drawable.pic2,
R.drawable.pic3,
R.drawable.pic4,
R.drawable.pic5,
R.drawable.pic6,
R.drawable.pic7
};
//声明 ImageAdapter
public ImageAdapter(Context c){
context = c;
}
@Override
//获取图片的个数
public int getCount() {
return imageInteger.length;
}
@Override
//获取图片在库中的位置
public Object getItem(int position) {
return position;
}
@Override
//获取图片在库中的位置
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView = new ImageView(context);
//给ImageView设置资源
imageView.setImageResource(imageInteger[position]);
//设置比例类型
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
//设置布局 图片128x192显示
imageView.setLayoutParams(new Gallery.LayoutParams(128, 192));
return imageView;
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?> <Gallery xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gallery" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_vertical" android:background="?android:galleryItemBackground" />
效果图：
Gallery和ImageSwitcher组件结合使用的例子：
MainActivity.java
package com.android.gallerytest;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Gallery.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;
public class MainActivity extends Activity implements OnItemSelectedListener,
ViewFactory {
private ImageSwitcher mSwitcher;
//大图片对应的缩略图源数组
private Integer[] mThumbIds = { R.drawable.sample_thumb_0,
R.drawable.sample_thumb_1, R.drawable.sample_thumb_2,
R.drawable.sample_thumb_3, R.drawable.sample_thumb_4,
R.drawable.sample_thumb_5, R.drawable.sample_thumb_6,
R.drawable.sample_thumb_7 };
//大图片源数组
private Integer[] mImageIds = { R.drawable.sample_0, R.drawable.sample_1,
R.drawable.sample_2, R.drawable.sample_3, R.drawable.sample_4,
R.drawable.sample_5, R.drawable.sample_6, R.drawable.sample_7 };
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//设置窗口无标题
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
mSwitcher = (ImageSwitcher) findViewById(R.id.switcher);
//注意在使用一个ImageSwitcher之前，
//一定要调用setFactory方法，要不setImageResource这个方法会报空指针异常。
mSwitcher.setFactory(this);
//设置动画效果
mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));
Gallery g = (Gallery) findViewById(R.id.gallery);
//添加OnItemSelectedListener监听器
g.setAdapter(new ImageAdapter(this));
g.setOnItemSelectedListener(this);
}
//创建内部类ImageAdapter
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mThumbIds[position]);
//设置边界对齐
i.setAdjustViewBounds(true);
//设置布局参数
i.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
//设置背景资源
i.setBackgroundResource(R.drawable.picture_frame);
return i;
}
private Context mContext;
}
@Override
//实现onItemSelected()方法，更换图片
public void onItemSelected(AdapterView<?> adapter, View v, int position,
long id) {
//设置图片资源
mSwitcher.setImageResource(mImageIds[position]);
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
@Override
//实现makeView()方法，为ImageView设置布局格式
public View makeView() {
ImageView i = new ImageView(this);
//设置背景颜色
i.setBackgroundColor(0xFF000000);
//设置比例类型
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
//设置布局参数
i.setLayoutParams(new ImageSwitcher.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
return i;
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<ImageSwitcher
android:id="@+id/switcher"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
/>
<Gallery
android:id="@+id/gallery"
android:background="#55000000"
android:layout_width="fill_parent"
android:layout_height="60dp"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:gravity="center_vertical"
android:spacing="16dp"
/>
</RelativeLayout>
效果图:
二.GridView的简介
GridView(网格视图)是按照行列的方式来显示内容的，一般用于显示图片，图片等内容，比如实现九宫格图，用GridView是首选，也是最简单的。主要用于设置Adapter。
GridView常用的XML属性：
|
属性名称
|
描述
|
|
android:columnWidth
|
设置列的宽度。
|
|
android:gravity
|
设置此组件中的内容在组件中的位置。可选的值有：top、bottom、left、right、center_vertical、fill_vertical、center_horizontal、fill_horizontal、center、fill、clip_vertical 可以多选，用“|”分开。
|
|
android:horizontalSpacing
|
两列之间的间距。
|
|
android:numColumns
|
设置列数。
|
|
android:stretchMode
|
缩放模式。
|
|
android:verticalSpacing
|
两行之间的间距。
|
下面有三个例子，第一个是只显示图片的，第二个是显示图片文字的(这里的图片是Android系统自带的图片)，第三个是显示自定义的图片文字。前面两个例子的实现都不是很难，第三个例子的实现有些复杂，学习GridView的时候，就想着能不能自定义自己喜欢的图片加上文字，在网上找些资料，一般都是第二个例子的形式的，最后在视频学习上找到了能实现自定义自己的图片的例子。自己就照着例子去学习，修改成了第三个例子。
第一个例子：
MainActivity.java
package com.android.gridview.activity;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
GridView gv = (GridView)findViewById(R.id.GridView1);
//为GridView设置适配器
gv.setAdapter(new MyAdapter(this));
//注册监听事件
gv.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View v, int position, long id)
{
Toast.makeText(MainActivity.this, "pic" + position, Toast.LENGTH_SHORT).show();
}
});
}
}
//自定义适配器
class MyAdapter extends BaseAdapter{
//上下文对象
private Context context;
//图片数组
private Integer[] imgs = {
R.drawable.pic0, R.drawable.pic1, R.drawable.pic2,
R.drawable.pic3, R.drawable.pic4, R.drawable.pic5,
R.drawable.pic6, R.drawable.pic7, R.drawable.pic8,
R.drawable.pic0, R.drawable.pic1, R.drawable.pic2,
R.drawable.pic3, R.drawable.pic4, R.drawable.pic5,
R.drawable.pic6, R.drawable.pic7, R.drawable.pic8,
};
MyAdapter(Context context){
this.context = context;
}
public int getCount() {
return imgs.length;
}
public Object getItem(int item) {
return item;
}
public long getItemId(int id) {
return id;
}
//创建View方法
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(context);
imageView.setLayoutParams(new GridView.LayoutParams(75, 75));//设置ImageView对象布局
imageView.setAdjustViewBounds(false);//设置边界对齐
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);//设置刻度的类型
imageView.setPadding(8, 8, 8, 8);//设置间距
}
else {
imageView = (ImageView) convertView;
}
imageView.setImageResource(imgs[position]);//为ImageView设置图片资源
return imageView;
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<GridView
android:id="@+id/GridView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:columnWidth="90dp"
android:numColumns="3"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:stretchMode="columnWidth"
android:gravity="center"
/>
</LinearLayout>
效果图：
第二个例子：
MainActivity.java
package com.android.gridview2.activity;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.widget.GridView;
import android.widget.SimpleAdapter;
public class MainActivity extends Activity {
private GridView gv;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.gridview);
//准备要添加的数据条目
List<Map<String, Object>> items = new ArrayList<Map<String,Object>>();
for (int i = 0; i < 9; i++) {
Map<String, Object> item = new HashMap<String, Object>();
item.put("imageItem", R.drawable.icon);//添加图像资源的ID
item.put("textItem", "icon" + i);//按序号添加ItemText
items.add(item);
}
//实例化一个适配器
SimpleAdapter adapter = new SimpleAdapter(this,
items,
R.layout.grid_item,
new String[]{"imageItem", "textItem"},
new int[]{R.id.image_item, R.id.text_item});
//获得GridView实例
gv = (GridView)findViewById(R.id.mygridview);
//为GridView设置适配器
gv.setAdapter(adapter);
}
}
gridview.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" > <GridView android:id="@+id/mygridview" android:numColumns="3" android:gravity="center_horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content" android:stretchMode="columnWidth" /> </LinearLayout>
grid_item.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/RelativeLayout1" android:layout_width="wrap_content" android:layout_height="fill_parent" android:paddingBottom="6dip" > <ImageView android:id="@+id/image_item" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" /> <TextView android:id="@+id/text_item" android:layout_below="@+id/image_item" android:layout_height="wrap_content" android:layout_width="wrap_content" android:layout_centerHorizontal="true" /> </RelativeLayout>
效果图：
第三个例子：
MainActivity.java
package com.android.gridview3;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
public class MainActivity extends Activity
{
private GridView gridView;
//图片的文字标题
private String[] titles = new String[]
{ "pic1", "pic2", "pic3", "pic4", "pic5", "pic6", "pic7", "pic8", "pic9"};
//图片ID数组
private int[] images = new int[]{
R.drawable.pic1, R.drawable.pic2, R.drawable.pic3,
R.drawable.pic4, R.drawable.pic5, R.drawable.pic6,
R.drawable.pic7, R.drawable.pic8,R.drawable.pic9
};
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
gridView = (GridView) findViewById(R.id.gridview);
PictureAdapter adapter = new PictureAdapter(titles, images, this);
gridView.setAdapter(adapter);
gridView.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View v, int position, long id)
{
Toast.makeText(MainActivity.this, "pic" + (position+1), Toast.LENGTH_SHORT).show();
}
});
}
}
//自定义适配器
class PictureAdapter extends BaseAdapter{
private LayoutInflater inflater;
private List<Picture> pictures;
public PictureAdapter(String[] titles, int[] images, Context context)
{
super();
pictures = new ArrayList<Picture>();
inflater = LayoutInflater.from(context);
for (int i = 0; i < images.length; i++)
{
Picture picture = new Picture(titles[i], images[i]);
pictures.add(picture);
}
}
@Override
public int getCount()
{
if (null != pictures)
{
return pictures.size();
} else
{
return 0;
}
}
@Override
public Object getItem(int position)
{
return pictures.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)
{
convertView = inflater.inflate(R.layout.picture_item, null);
viewHolder = new ViewHolder();
viewHolder.title = (TextView) convertView.findViewById(R.id.title);
viewHolder.image = (ImageView) convertView.findViewById(R.id.image);
convertView.setTag(viewHolder);
} else
{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.title.setText(pictures.get(position).getTitle());
viewHolder.image.setImageResource(pictures.get(position).getImageId());
return convertView;
}
}
class ViewHolder
{
public TextView title;
public ImageView image;
}
class Picture
{
private String title;
private int imageId;
public Picture()
{
super();
}
public Picture(String title, int imageId)
{
super();
this.title = title;
this.imageId = imageId;
}
public String getTitle()
{
return title;
}
public void setTitle(String title)
{
this.title = title;
}
public int getImageId()
{
return imageId;
}
public void setImageId(int imageId)
{
this.imageId = imageId;
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?> <GridView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gridview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:columnWidth="90dp" android:numColumns="auto_fit" android:verticalSpacing="10dp" android:horizontalSpacing="10dp" android:stretchMode="columnWidth" android:gravity="center" />
picture_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/root"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
>
<ImageView
android:id="@+id/image"
android:layout_width="100dp"
android:layout_height="150dp"
android:layout_gravity="center"
android:scaleType="fitXY"
android:padding="4dp"
/>
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center_horizontal"
/>
</LinearLayout>
效果图：
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