我正在尝试制作一个图像寻呼机,根据我查找的所有教程,看来它已经正确完成了,但是我得到的只是一个空白屏幕。适配器的instantiateItem
方法上的断点告诉我它正在被调用,并且所有正确的信息都已放入视图中,甚至可以滑动,但是我仍然看不到任何东西。这是我的代码
activity_photos.xml
<RelativeLayout> // I'm not including that code, irrelevant.
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/imagePager"
android:background="@android:color/black"/>
</RelativeLayout>
viewpager_itemx.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:id="@+id/imageView"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/imageLabel"
android:textColor="@android:color/white"/>
</LinearLayout>
PhotosActivity.java
final String[] images = getResources().getStringArray(R.array.tips_images);
final String[] labels = getResources().getStringArray(R.array.tips_text);
final ViewPager viewPager = (ViewPager) findViewById(R.id.imagePager);
final ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(PhotoTipsActivity.this, images, labels);
viewPager.setAdapter(viewPagerAdapter);
最后是ViewPagerAdapter.java
公共类ViewPagerAdapter扩展了PagerAdapter {
private Context context;
private String[] images;
private String[] labels;
public ViewPagerAdapter(Context context, String[] images, String[] labels) {
this.context = context;
this.images = images;
this.labels = labels;
}
@Override
public int getCount() {
return images.length;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
final View itemView = LayoutInflater.from(context).inflate(R.layout.viewpager_item, container, false);
final ImageView imageView = (ImageView) itemView.findViewById(R.id.imageView);
final TextView imageLabel = (TextView) itemView.findViewById(R.id.imageLabel);
// Get drawable image.
final int imageId = context.getResources().getIdentifier(images[position], "drawable", context.getPackageName());
imageView.setImageResource(imageId);
imageLabel.setText(labels[position]);
return itemView;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView(((LinearLayout) object));
}
}
有什么明显的原因为什么我看不到我的图像?
最佳答案
destroyItem()
需要从容器中删除视图的方式相同,instantiateItem()
需要将视图添加到容器中。
只需添加
container.addView(itemView);
从
instantiateItem()
返回之前,您就可以做生意。