Android开发中画廊视图Gallery的两种使用方法分析

<?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>

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;
}
}

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();
}
}
}

<?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>

<?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>

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;
}
}
}