我只是在学习回收器视图，无法弄清楚为什么带有android：id="@+id/im_item_icon"的图像视图不会显示在屏幕上。我什至还有另一个可以工作的imageView，但是当我交换ID时，原始的不工作视图可以工作，而工作视图将无法正常工作。所以基本上问题一定出在ID上，但我无法弄清楚为什么。顺便说一句，我从博客"http://wiseassblog.com/tutorials/2016/03/04/how-to-build-a-recyclerview/"中获得了代码
转换器适配器.java
public class DerpAdapter extends RecyclerView.Adapter<DerpAdapter.DerpHolder> {
private List<ListItem> listData;
private LayoutInflater inflater;
public DerpAdapter(List<ListItem> listData, Context c){
inflater = LayoutInflater.from(c);
this.listData = listData;
}
@Override
public DerpAdapter.DerpHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.list_item, parent, false);
return new DerpHolder(view);
}
@Override
public void onBindViewHolder(DerpHolder holder, int position) {
ListItem item = listData.get(position);
holder.title.setText(item.getTitle());
holder.icon.setImageResource(item.getImageResId());
}
@Override
public int getItemCount() {
return listData.size();
}
class DerpHolder extends RecyclerView.ViewHolder {
private TextView title;
private ImageView icon;
private View container;
public DerpHolder(View itemView) {
super(itemView);
title = (TextView)itemView.findViewById(R.id.lbl_item_text);
icon = (ImageView)itemView.findViewById(R.id.im_item_icon);
//We'll need the container later on, when we add an View.OnClickListener
container = itemView.findViewById(R.id.cont_item_root);
}
}
德普数据.java
public class DerpData {
private static final String[] titles = {"Nothingness cannot be defined",
"Time is like a river made up of the events which happen, and a violent stream; " +
"for as soon as a thing has been seen, it is carried away, and another comes" +
" in its place, and this will be carried away too,",
"But when I know that the glass is already broken, every minute with it is precious.",
"For me, it is far better to grasp the Universe as it really is than to persist in" +
" delusion, however satisfying and reassuring.",
"The seeker after the truth is not one who studies the writings of the ancients and," +
" following his natural disposition, puts his trust in them, but rather the" +
" one who suspects his faith in them and questions what he gathers from them," +
" the one who submits to argument and demonstration, and not to the " +
"sayings of a human being whose nature is fraught with all kinds " +
"of imperfection and deficiency.",
"You must take personal responsibility. You cannot change the circumstances, the" +
" seasons, or the wind, but you can change yourself. That is something you" +
" have charge of."
};
private static final String[] subTitles = {"Bruce Lee",
"Marcus Aurelius",
"Meng Tzu",
"Ajahn Chah",
"Carl Sagan",
"Alhazen",
"Jim Rohn"
};
private static final int icon = R.drawable.ic_tonality_black_36dp;
public static List <ListItem> getListData() {
List <ListItem> data = new ArrayList <>();
//Repeat process 4 times, so that we have enough data to demonstrate a scrollable
//RecyclerView
for (int x = 0; x < 4; x++) {
//create ListItem with dummy data, then add them to our List
for (int i = 0; i < titles.length; i++) {
ListItem item = new ListItem();
item.setTitle(titles[i]);
item.setSubTitle(subTitles[i]);
data.add(item);
}
}
return data;
}
列表项.java
public class ListItem {
private int imageResId;
private String subTitle;
private String title;
private boolean favourite = false;
public String getSubTitle() {
return subTitle;
}
public void setSubTitle(String subTitle) {
this.subTitle = subTitle;
}
public boolean isFavourite() {
return favourite;
}
public void setFavourite(boolean favourite) {
this.favourite = favourite;
}
public int getImageResId() {
return imageResId;
}
public void setImageResId(int imageResId) {
this.imageResId = imageResId;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
详细活动.java
public class DetailActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail);
}
列表活动.java
public class ListActivity extends AppCompatActivity {
private RecyclerView recView;
private DerpAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
recView = (RecyclerView)findViewById(R.id.rec_list);
//Check out GridLayoutManager and StaggeredGridLayoutManager for more options
recView.setLayoutManager(new LinearLayoutManager(this));
adapter = new DerpAdapter(DerpData.getListData(), this);
recView.setAdapter(adapter);
}
activity_detail.xml
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="16dp"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="16dp"
tools:context="application.binarysoup.jsonpractice.ui.DetailActivity">
<TextView
android:id="@+id/lbl_quote_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-medium" />
<TextView
android:id="@+id/lbl_quote_attribution"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/lbl_quote_text"
android:fontFamily="sans-serif-light"
android:textStyle="italic" />
activity_list.xml
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="application.binarysoup.jsonpractice.ui.ListActivity"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="81dp">
<android.support.v7.widget.RecyclerView
android:id="@+id/rec_list"
android:layout_width="match_parent"
android:layout_height="match_parent" />
list_item.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/cont_item_root"
android:layout_width="match_parent"
android:layout_height="72dp"
android:background="@drawable/background_state_drawable"
android:clickable="true"
>
<ImageView
android:id="@+id/im_item_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:paddingLeft="16dp"
android:src="@drawable/ic_tonality_black_36dp" />
<TextView
android:id="@+id/lbl_item_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/im_item_icon"
android:layout_marginLeft="72dp"
android:layout_marginRight="48dp"
android:ellipsize="end"
android:fontFamily="sans-serif"
android:singleLine="true"
android:text="Sois comme l'eau mon ami"
android:textColor="@android:color/black"
android:textSize="16sp" />
<TextView
android:id="@+id/lbl_item_sub_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/lbl_item_text"
android:layout_marginLeft="72dp"
android:layout_marginRight="48dp"
android:ellipsize="end"
android:fontFamily="sans-serif"
android:singleLine="true"
android:text="Mononc' J"
android:textSize="14sp" />
<ImageView
android:id="@+id/im_item_icon_secondary"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:clickable="true"
android:padding="16dp"
android:src="@drawable/ic_star_border_black_24dp"
android:background="@drawable/background_state_drawable"
/>
无法让 ImageView 显示在回收器视图上
您必须初始化 imageResId 才能将其显示在回收器视图中
for (int i = 0; i < titles.length; i++) {
ListItem item = new ListItem();
item.setTitle(titles[i]);
item.setSubTitle(subTitles[i]);
//put the code to initialise the imageResId here
data.add(item);
}