android recycleview 的使用

 1 public class NerdLauncherFragment extends Fragment {
 2     private static final String TAG = "NerdLauncherFragment";
 3     private RecyclerView mRecyclerView;
 4     public static NerdLauncherFragment newInstance() {
 5         return new NerdLauncherFragment();
 6     }
 7 
 8     @Nullable
 9     @Override
10     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
11         View v = inflater.inflate(R.layout.fragment_nerd_launcher, container, false);
12         mRecyclerView= (RecyclerView) v.findViewById(R.id.fragment_nerd_launcher_recycler_view);
13         mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
14         setupAdapter();
15         return v;
16     }
17 
18     private void setupAdapter() {
19         Intent startupIntent = new Intent(Intent.ACTION_MAIN);
20         startupIntent.addCategory(Intent.CATEGORY_LAUNCHER);
21         PackageManager pm = getActivity().getPackageManager();
22         List<ResolveInfo> activities = pm.queryIntentActivities(startupIntent, 0);
23         Collections.sort(activities, new Comparator<ResolveInfo>() {
24             @Override
25             public int compare(ResolveInfo lhs, ResolveInfo rhs) {
26                 PackageManager pm = getActivity().getPackageManager();
27                 return String.CASE_INSENSITIVE_ORDER.compare(lhs.loadLabel(pm).toString(),rhs.loadLabel(pm).toString());
28             }
29         });
30         Log.i(TAG, "Found " + activities.size() + " activities.");
31         mRecyclerView.setAdapter(new ActivityAdapter(activities));
32     }
33     private class ActivityHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
34 
35         private ResolveInfo mResolveInfo;
36         private TextView mNameTextView;
37         private ImageView mImageView;
38 
39         public ActivityHolder(View itemView) {
40             super(itemView);
41             mNameTextView= (TextView) itemView.findViewById(R.id.textView);
42             mImageView= (ImageView) itemView.findViewById(R.id.imageView);
43             mNameTextView.setOnClickListener(this);
44         }
45         public void bindActivity(ResolveInfo resolveInfo){
46             mResolveInfo=resolveInfo;
47             PackageManager pm = getActivity().getPackageManager();
48             String appName = mResolveInfo.loadLabel(pm).toString();
49             mNameTextView.setText(appName);
50             Drawable icon = mResolveInfo.loadIcon(pm);
51             mImageView.setImageDrawable(icon);
52         }
53 
54         @Override
55         public void onClick(View v) {
56             ActivityInfo activityInfo = mResolveInfo.activityInfo;
57             Intent i = new Intent(Intent.ACTION_MAIN).setClassName(activityInfo.applicationInfo.packageName, activityInfo.name).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
58             startActivity(i);
59         }
60     }
61     private class ActivityAdapter extends RecyclerView.Adapter<ActivityHolder>{
62 
63         private final List<ResolveInfo> mActivities;
64 
65         public ActivityAdapter(List<ResolveInfo> activities){
66             mActivities = activities;
67         }
68         @Override
69         public ActivityHolder onCreateViewHolder(ViewGroup parent, int viewType) {
70             View view = LayoutInflater.from(getActivity()).inflate(R.layout.list_item, parent, false);
71             return new ActivityHolder(view);
72         }
73 
74         @Override
75         public void onBindViewHolder(ActivityHolder holder, int position) {
76             ResolveInfo resolveInfo = mActivities.get(position);
77             holder.bindActivity(resolveInfo);
78         }
79 
80         @Override
81         public int getItemCount() {
82             return mActivities.size();
83         }
84     }
85 }

fragment_nerd_launcher:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fragment_nerd_launcher_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</android.support.v7.widget.RecyclerView>

list_item:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

首先写一个类集成Fragment  

在onCreateView中用inflate添加一个布局文件,用布局文件找到对应的recycleview,并recycleview.setLayoutManager(new LinearLayoutManager(getActivity()));然后setadapter();

写一个内部类继承RecyclerView.ViewHolder,这个类的构造方法主要是找到控件并设置监听事件.然后写一个方法,这个方法主要是显示recycleview的条目.

然后再写一个内部类继承RecyclerView.Adapter<写上面写的那个viewholder>,重写三个方法onCreateViewHolder,onBindViewHolder,getItemCount.其中onCreateViewHolder方法中托管一个布局作为viewholfer的样式,就像listview的条目,
在onBindViewHolder方法中调用viewholder中的方法.在getItemCount方法中返回recycleview条目的个数.