根据Google文档,Gallery类在API level 16已被弃用,这个小部件不再受支持。其他水平滚动小部件包括support库中的HorizontalScrollView和ViewPager。所以我使用ViewPager作为Gallery类的替代品。
我的目标是最终实现一个带有文本描述的无限滚动图片ViewPager。我使用以下代码来实现图片ViewPager及其每张图像的文本描述,但是如何应用无限滚动到ViewPager中呢?
我之前没有使用过ViewPager,所以如果可能,请尽量提供详细的代码。
activity_main.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="@+id/myimagepager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
custom_pager.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center_horizontal">
<ImageView
android:id="@+id/myimage"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_margin="5dp"
android:layout_weight="2" />
<TextView
android:id="@+id/image_text"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>
ImagePager:
public class ImagePager extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImagePagerAdapter adapter = new ImagePagerAdapter(this, imageArra, stringArray );
ViewPager myPager = (ViewPager) findViewById(R.id.myimagepager);
myPager.setAdapter(adapter);
myPager.setCurrentItem(0);
}
private int imageArra[] = { R.drawable.a, R.drawable.b,R.drawable.c,
R.drawable.d,R.drawable.e,R.drawable.f,
R.drawable.g, R.drawable.h, R.drawable.i};
private String[] stringArray = new String[] { "Image a", "Image b","Image c"
"Image d","Image e","Image f",
"Image g","Image h","Image i"};
}
ImagePagerAdapter:
public class ImagePagerAdapter extends PagerAdapter {
Activity activity;
int imageArray[];
String[] stringArray;
public ImagePagerAdapter(Activity act, int[] imgArra, String[] stringArra) {
imageArray = imgArra;
activity = act;
stringArray = stringArra;
}
public int getCount() {
return imageArray.length;
}
public Object instantiateItem(View collection, int position) {
LayoutInflater inflater = (LayoutInflater)collection.getContext
().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.custom_pager, null);
ImageView im=(ImageView) layout.findViewById(R.id.myimage);
im.setImageResource(imageArray[position]);
TextView txt=(TextView) layout.findViewById(R.id.image_text);
txt.setText(stringArray[position]);
((ViewPager) collection).addView(layout, 0);
return layout;
}
@Override
public void destroyItem(View arg0, int arg1, Object arg2) {
((ViewPager) arg0).removeView((View) arg2);
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == ((View) arg1);
}
@Override
public Parcelable saveState() {
return null;
}
}
Gallery
的文档。前三句话说:“此类已在 API 级别 16 中弃用。不再支持此小部件。其他水平滚动小部件包括来自支持库的HorizontalScrollView
和ViewPager
。”所以,给大家一个提示,以后在做任何事情之前,先读一下文档吧。;) - Andrew Thompson