Android基础类之BaseAdapter
BaseAdapter是实现了ListAdapter和SpinnerAdapter两个接口，当然它也可以直接给ListView和Spinner等UI组件直接提供数据。
说明：上面一行图片是Gallery画廊，每次点击一个Gallery图片时，会同时在下面以大图形式显示出来该图片
<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
android:orientation=”vertical”
android:layout_width=”fill_parent”
android:layout_height=”fill_parent”
>
<TextView
android:layout_width=”fill_parent”
android:layout_height=”wrap_content”
android:text=”@string/hello”
/>
<Gallery
android:id=”@+id/gallery1″
android:layout_width=”match_parent”
android:spacing=”5px”
android:layout_height=”wrap_content”
></Gallery>
<ImageView
android:id=”@+id/iv”
android:layout_gravity=”center_vertical”
android:layout_marginTop=”20px”
android:layout_width=”320px”
android:layout_height=”320px”
></ImageView>
</LinearLayout>
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;
public class MainActivity extends Activity {
private Gallery gallery;
private ImageView imgview;
private int[] imgs = {R.drawable.a6,R.drawable.a1,R.drawable.a2,R.drawable.a3,R.drawable.a4,R.drawable.a5};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
imgview = (ImageView)findViewById(R.id.iv);
gallery = (Gallery)findViewById(R.id.gallery1);
MyImgAdapter adapter = new MyImgAdapter(this);
gallery.setAdapter(adapter);
gallery.setOnItemClickListener(new OnItemClickListener() {
//用户点击图片时，将该图片的ResourceID设到下面的ImageView中去，
@Override
public void onItemClick(AdapterView<?> arg0, View view, int position,
long arg3) {
imgview.setImageResource(imgs[position]);
}
});
}
class MyImgAdapter extends BaseAdapter {
//自定义图片Adapter以内部类形式存在于MainActivity中，方便访问MainActivity中的各个变量，特别是imgs数组
private Context context;//用于接收传递过来的Context对象
public MyImgAdapter(Context context) {
super();
this.context = context;
}
/* (non-Javadoc)
* @see android.widget.Adapter#getCount()
*/
@Override
public int getCount() {
return imgs.length;
}
/* (non-Javadoc)
* @see android.widget.Adapter#getItem(int)
*/
@Override
public Object getItem(int position) {
return position;
}
/* (non-Javadoc)
* @see android.widget.Adapter#getItemId(int)
*/
@Override
public long getItemId(int position) {
return position;
}
/* (non-Javadoc)
* @see android.widget.Adapter#getView(int, android.view.View, android.view.ViewGroup)
*/
@Override
public View getView(int position, View convertView, ViewGroup parent) {
//针对每一个数据（即每一个图片ID）创建一个ImageView实例，
ImageView iv = new ImageView(context);//针对外面传递过来的Context变量，
iv.setImageResource(imgs[position]);
Log.i(“magc”, String.valueOf(imgs[position]));
iv.setLayoutParams(new Gallery.LayoutParams(80, 80));//设置Gallery中每一个图片的大小为80*80。
iv.setScaleType(ImageView.ScaleType.FIT_XY);
return iv;
}
}
}
