我有一个浏览器,用作杂志电子阅读器应用程序中的主要导航元素。我已经为每篇文章定义了一个扩展为“封面页”的布局,这些都显示得很好。但是,我想增加一个不同的布局,以在每 6 次查看时显示一个广告。所以,在 viewpager 适配器的 instantiateItem 方法上,我有以下语句if ((position != 0) && (position%6 == 0) && (adsShown < ads.size()))
:该程序启动良好,并且文章视图正确膨胀。但是,当我到达应该显示广告的位置时,视图是空白的。为什么是这样?
这是 instantiateItem 方法的完整代码:
@Override
public Object instantiateItem(View arg0, int position) {
if ((position != 0) && (position%2 == 0) && (adsShown < ads.size())){
View v = getLayoutInflater().inflate(R.layout.adview, null);
ImageView adImg = (ImageView)v.findViewById(R.id.adImage);
adImg.setImageBitmap(ads.get(adsShown).image);
v.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(ads.get(adsShown).linkURL));
startActivity(browserIntent);
}
});
adsShown++;
System.out.println("ADSSHOWN" + adsShown);
return v;
}
else{
Article s = toShow.get(position-adsShown);
View v = getLayoutInflater().inflate(R.layout.previewpage, null);
TextView hl = (TextView)v.findViewById(R.id.coverHl);
ImageView img = (ImageView)v.findViewById(R.id.coverImg);
TextView blurb = (TextView)v.findViewById(R.id.coverBlurb);
TextView author = (TextView)v.findViewById(R.id.coverAuthor);
TextView bot = (TextView)v.findViewById(R.id.coverBot);
hl.setText(s.title);
img.setImageBitmap(s.image);
blurb.setText(Html.fromHtml(s.excerpt));
author.setText("by "+ s.author.name);
bot.setText(s.cats.get(0).name + " // " + s.date);
v.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
Article topass = showing;
// System.out.println("XXYYZZAA: " + topass.headline);
intent.setClassName("com.calib.caliber", "com.calib.caliber.ArticleView");
// intent.putExtra("title", topass.title);
intent.putExtra("a", topass);
// intent.putExtra("author", topass.author.name);
// intent.putExtra("content", topass.content);
// intent.putExtra("id", topass.ID);
startActivityForResult(intent, 1);
}
});
((ViewPager) arg0).addView(v);
return v;
}
}
这是 adview 活动的 XML 布局文件:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000">
<TextView
android:id = "@+id/adText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text = "advertisement"
android:textColor="#FFFFFF"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"></TextView>
<ImageView
android:id = "@+id/adImage"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below = "@id/adText">
</ImageView>
</RelativeLayout>