[置顶] RecyclerView中的多种布局

概念

RecyclerView可以用于加载不同的视图类型，基于服务器的反馈，可能会要求加载不同的布局。我们需要在适配器中重写的方法：

getItemViewType(),onCreatViewHolder(),onBindViewHolder()

实现

首先在上一节的基础上我们要替换掉基础的

SimpleItemRecyclerViewAdapter

 而是用

ComplexRecyclerViewAdapter

 ,下面的例子将会包含两种布局

Layout_viewHolder1.xml

 用来存储User对象，而

layout_viewHolder2.xml

将会用来存储String对象。
在主活动中创建一个数据集合分别是文字和图像

private ArrayList<Object> getSampleArrayList() {
ArrayList<Object> items = new ArrayList<>();
items.add(new User("Dany Targaryen", "Valyria"));
items.add(new User("Rob Stark", "Winterfell"));
items.add("image");
items.add(new User("Jon Snow", "Castle Black"));
items.add("image");
items.add(new User("Tyrion Lanister", "King's Landing"));
return items;
}

1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
配置两种viewHolder用来展示数据

public class ViewHolder1 extends RecyclerView.ViewHolder {

private TextView label1, label2;

public ViewHolder1(View v) {
super(v);
label1 = (TextView) v.findViewById(R.id.text1);
label2 = (TextView) v.findViewById(R.id.text2);
}

public TextView getLabel1() {
return label1;
}

public void setLabel1(TextView label1) {
this.label1 = label1;
}

public TextView getLabel2() {
return label2;
}

public void setLabel2(TextView label2) {
this.label2 = label2;
}
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/llContainer"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp">

<TextView
android:id="@+id/text1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textStyle="bold"
android:textAppearance="?android:attr/textAppearanceListItemSmall"
android:gravity="center_vertical"/>

<TextView
android:id="@+id/text2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceListItemSmall"
android:gravity="center_vertical" />

</LinearLayout>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

3.创建复杂的适配器

ComplexRecyclerViewAdapter

public class ComplexRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
//在RecyclerView中展示的项
private List<Object> items;
//为了区分加入标签
private final int USER = 0 , IMAGE = 1;

public ComplexRecyclerViewAdapter(List<Object> items) {
this.items = items;
}
//获得适配器中的项的数量和类型

@Override
public int getItemCount() {
return this.items.size();
}
//获得项的类型
@Override
public int getItemViewType(int position) {
if (items.get(position) instanceof User) {
return USER;
} else if (items.get(position) instanceof String) {
return IMAGE;
}
return -1;
}
//将数据填充进viewHolder来展示
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
switch (RecyclerView.ViewHolder.getItemViewType()) {
case USER:
ViewHolder1 vh1 = (ViewHolder1) holder;//转型
configureViewHolder1(vh1, position);
break;
case IMAGE:
ViewHolder2 vh2 = (ViewHolder2) holder;
configureViewHolder2(vh2);
break;
default:
RecyclerViewSimpleTextViewHolder vh = (RecyclerViewSimpleTextViewHolder) holder;
confgureDefaultViewHolder(vh, position);
break;
}

}

//基于项不同的类型来获得不同的viewholder,

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder;
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
switch (viewType) {
case USER:
View v1 =inflater.inflate(R.layout.layout_viewholder1, parent, false);
viewHolder = new ViewHolder1(v1);
break;
case IMAGE:
View v2 = inflater.inflate(R.layout.layout_viewholder2, parent, false);
break;
default:
View v = inflater.inflate(android.R.layout.simple_list_item_1, parent, false);
viewHolder = new RecyclerViewSimpleTextViewHolder(v);
break;
}
return viewHolder;
}
//配置viewHolder展示数据
private void configureDefaultViewHolder(RecyclerViewSimpleTextViewHolder vh, int position) {
vh.getlabel().setText((CharSequence) items.get(position));
}
private void configureViewHolder1(ViewHolder1 vh1, int position) {
User user = (User) items.get(position);
if (user != null) {
vh1.getLabel1().setText("Name:" + user.name);
vh1.getLabel2().setText("Hometown" + user.hometown);
}
}
private void configureViewHolder2(ViewHolder2 vh2) {
vh2.getImagView().setImageResource(R.mipmap.ic_launcher);
}

}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82

最后在主活动中 

recyclerView.setAdapter(new ComplexRecyclerViewAdapter(getSampleArrayList()));