Android之Gallery的两种使用方法

第一种方法：

第一步：设计xml布局文件 

代码如下：main.xm

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

    <Gallery

        android:id="@+id/myGallery"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:gravity="center_vertical"

        android:spacing="3px"

        android:text="@string/hello" />

</LinearLayout>

第二步：自定义一个适配器，这个适配器继承BaseAdapter这个类

代码如下：

package net.loonggg.gallery;

import android.content.Context;

import android.view.View;

import android.view.ViewGroup;

import android.view.ViewGroup.LayoutParams;

import android.widget.BaseAdapter;

import android.widget.Gallery;

import android.widget.ImageView;

public class ImageGalleryAdapter extends BaseAdapter {

private Context context;

// 里面所有的方法表示的是可以根据指定的显示图片的数量,进行每个图片的处理

private int[] image = new int[] { R.drawable.ispic_a, R.drawable.ispic_b,

R.drawable.ispic_c, R.drawable.ispic_d, R.drawable.ispic_e };

public ImageGalleryAdapter(Context context) {

this.context = context;

}

public int getCount() { // 取得要显示内容的数量

return image.length;

}

public Object getItem(int position) { // 每个资源的位置

return image[position];

}

public long getItemId(int position) { // 取得每个项的ID

return image[position];

}

// 将资源设置到一个组件之中，很明显这个组件是ImageView

public View getView(int position, View convertView, ViewGroup parent) {

ImageView iv = new ImageView(context);

iv.setBackgroundColor(0xFFFFFFFF);

iv.setImageResource(image[position]);// 给ImageView设置资源

iv.setScaleType(ImageView.ScaleType.CENTER);// 设置对齐方式

iv.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT,

LayoutParams.WRAP_CONTENT));

return iv;

}

}

第三步：主方法：

package net.loonggg.gallery;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.Gallery;

import android.widget.Toast;

public class GalleryActivity extends Activity {

private Gallery myGallery;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

myGallery = (Gallery) findViewById(R.id.myGallery);

myGallery.setAdapter(new ImageGalleryAdapter(this));

myGallery.setOnItemClickListener(new OnItemClickListenerImpl());

}

private class OnItemClickListenerImpl implements OnItemClickListener {

public void onItemClick(AdapterView<?> parent, View view, int position,

long id) {

Toast.makeText(GalleryActivity.this, String.valueOf(position),

Toast.LENGTH_SHORT).show();

}

}

}

第二种方法：

第一步：设计xml布局文件 

代码如下：main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:gravity="bottom"

    android:orientation="vertical" >

    <ImageSwitcher

        android:id="@+id/is"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content" >

    </ImageSwitcher>

    <Gallery

        android:id="@+id/myGallery"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:gravity="center_vertical"

        android:spacing="3px" />

</LinearLayout>

gallery_item.xml文件：

代码如下：

<?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"

    android:background="#FFFFFF"

    android:orientation="horizontal" >

    <ImageView

        android:id="@+id/iv"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:scaleType="center" />

</LinearLayout>

第二步：MainActivity

代码如下：

package net.loonggg.gallery2;

import java.lang.reflect.Field;

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.view.View;

import android.view.ViewGroup.LayoutParams;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.Gallery;

import android.widget.ImageSwitcher;

import android.widget.ImageView;

import android.widget.SimpleAdapter;

import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity {

private ImageSwitcher is;

private Gallery gallery;

private SimpleAdapter adapter;

private List<Map<String, Integer>> list = new ArrayList<Map<String, Integer>>();

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

is = (ImageSwitcher) findViewById(R.id.is);

is.setFactory(new ViewFactoryImpl());

initAdapter();

gallery = (Gallery) findViewById(R.id.myGallery);

gallery.setAdapter(adapter); // 为gallery设置合适的适配器

gallery.setOnItemClickListener(new OnItemClickListenerImpl());

}

public class OnItemClickListenerImpl implements OnItemClickListener { // gallery的点击事件

@Override

public void onItemClick(AdapterView<?> parent, View view, int position,

long id) {

Map<String, Integer> map = (Map<String, Integer>) parent

.getAdapter().getItem(position);

is.setImageResource(map.get("image"));

}

}

public void initAdapter() { // 这个方法的功能是：从R.java文件中获取图片资源的id,如果资源图片数量比较多，用数组的方法一一定义，就不太合适，这种方法最好了。

Field[] fields = R.drawable.class.getDeclaredFields();

for (int x = 0; x < fields.length; x++) {

if (fields[x].getName().startsWith("ispic_")) { // 根据图片的名称取出想要的图片

Map<String, Integer> map = new HashMap<String, Integer>();

try {

map.put("image", fields[x].getInt(R.drawable.class));

} catch (Exception e) {

e.printStackTrace();

}

list.add(map);

}

}

adapter = new SimpleAdapter(MainActivity.this, list,

R.layout.grid_item, new String[] { "image" },

new int[] { R.id.iv });

}

public class ViewFactoryImpl implements ViewFactory {

@Override

public View makeView() {

ImageView iv = new ImageView(MainActivity.this);

iv.setBackgroundColor(0xFFFFFFFF);

iv.setScaleType(ImageView.ScaleType.CENTER);

iv.setLayoutParams(new ImageSwitcher.LayoutParams(

LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));

return iv;

}

}

}