5.2 Android Basic QuickStart Widgets&Other View Gallery
Gallery
Gallery是一个水平滚动项的布局控件。
本演练将创建一个相册走廊，同时显示选中的图片信息。
- 新建项目HelloGallery。
-
将使用的图片放入res/drawable目录。
3. 打开res/layout/main.xml文件编辑如下。
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout android:id="@+id/FrameLayout01"
android:layout_width="fill_parent" android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<Gallery android:background="#55000000"
android:id="@+id/gallery"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical"
android:spacing="16dp"/>
</FrameLayout>
4. 打开HelloGallery.java 修改onCreate()方法。
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Gallery g = (Gallery)findViewById(R.id.gallery);
g.setAdapter(new ImageAdapter(this));
g.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int position,
long id) {
Toast.makeText(HelloGallery.this, ""+position, Toast.LENGTH_SHORT).show();
}
});
}
5. 在res/values下创建attrs.xml文件，编辑内容如下。
<?xml version="1.0" encoding="UTF-8"?>
<resources>
<declare-styleable name="HelloGallery">
<attr name="android:galleryItemBackground"/>
</declare-styleable>
</resources>
6. 返回hellogallery.java 自定义ImageAdapter类。
public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private Integer[] mImageIds = { 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 };
public ImageAdapter(Context c) {
mContext = c;
TypedArray a = obtainStyledAttributes(R.styleable.HelloGallery);
mGalleryItemBackground = a.getResourceId(
R.styleable.HelloGallery_android_galleryItemBackground, 0);
a.recycle();
}
public int getCount() {
return mImageIds.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(mImageIds[position]);
i.setLayoutParams(new Gallery.LayoutParams(150, 100));
i.setScaleType(ImageView.ScaleType.FIT_XY);
i.setBackgroundResource(mGalleryItemBackground);
return i;
}
}
7. 运行程序。
author: im@xingquan.org
