android如何实现图片预览
main.xml
先定义一个GridView，然后再定义一个ImageSwitcher
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<GridView
android:id="@+id/gridView1"
android:layout_height="fill_parent"
android:layout_width="300px"
android:layout_marginTop="6px"
android:horizontalSpacing="3px"
android:verticalSpacing="3px"
android:numColumns="4"/>
<ImageSwitcher
android:id="@+id/imageSwicher1"
android:padding="20px"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
></ImageSwitcher>
</LinearLayout>
MainActivity代码如下
public class MainActivity extends Activity {
private int[] imageId = new int[] { R.drawable.w1, R.drawable.w2,
R.drawable.w3, R.drawable.w4, R.drawable.w5, R.drawable.w6 };
private ImageSwitcher imageSwitcher;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwicher1);
imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));// 设置淡入动画
imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));// 设置谈出动画
imageSwitcher.setFactory(new ViewFactory() {
@Override
public View makeView() {
// TODO Auto-generated method stub
ImageView imageView = new ImageView(MainActivity.this);// 实例化一个ImageView类的对象
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);// 设置保持纵横比居中缩放图像
imageView.setLayoutParams(new ImageSwitcher.LayoutParams(// 主要要是用ImageSwitcher的LayoutParams
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
return imageView;
}
});
imageSwitcher.setImageResource(imageId[0]);
GridView gridView = (GridView) findViewById(R.id.gridView1);
BaseAdapter adapter = new BaseAdapter() {
/*
* 获得数量
*
* @see android.widget.Adapter#getCount()
*/
@Override
public int getCount() {
// TODO Auto-generated method stub
return imageId.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
/**
* 获得当前选项
*/
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(MainActivity.this);
/** 设置图像的宽度和高度 **/
imageView.setAdjustViewBounds(true);
imageView.setMaxWidth(150);
imageView.setMaxHeight(113);
imageView.setPadding(5, 5, 5, 5);
} else {
imageView = (ImageView) convertView;
}
imageView.setImageResource(imageId[position]);
return imageView;
}
};
gridView.setAdapter(adapter);
gridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
imageSwitcher.setImageResource(imageId[arg2]);// 显示选中的图片
}
});
}
}
