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
83
84
85
86
87
88
|
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.databinding;
import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
/**
* BindingAdapter is applied to methods that are used to manipulate how values with expressions
* are set to views. The simplest example is to have a public static method that takes the view
* and the value to set:
* <p><pre>
*<code>@BindingAdapter("android:bufferType")
* public static void setBufferType(TextView view, TextView.BufferType bufferType) {
* view.setText(view.getText(), bufferType);
* }</code></pre>
* In the above example, when android:bufferType is used on a TextView, the method
* setBufferType is called.
* <p>
* It is also possible to take previously set values, if the old values are listed first:
* <p><pre>
*<code>@BindingAdapter("android:onLayoutChange")
* public static void setOnLayoutChangeListener(View view, View.OnLayoutChangeListener oldValue,
* View.OnLayoutChangeListener newValue) {
* if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
* if (oldValue != null) {
* view.removeOnLayoutChangeListener(oldValue);
* }
* if (newValue != null) {
* view.addOnLayoutChangeListener(newValue);
* }
* }
* }</code></pre>
* When a binding adapter may also take multiple attributes, it will only be called when all
* attributes associated with the binding adapter have binding expressions associated with them.
* This is useful when there are unusual interactions between attributes. For example:
* <p><pre>
*<code>@BindingAdapter({"android:onClick", "android:clickable"})
* public static void setOnClick(View view, View.OnClickListener clickListener,
* boolean clickable) {
* view.setOnClickListener(clickListener);
* view.setClickable(clickable);
* }</code></pre>
* The order of the parameters must match the order of the attributes in values in the
* BindingAdapter.
* <p>
* A binding adapter may optionally take a class extending DataBindingComponent as the first
* parameter as well. If it does, it will be passed the value passed in during binding, either
* directly in the inflate method or indirectly, using the value from
* {@link DataBindingUtil#getDefaultComponent()}.
* <p>
* If a binding adapter is an instance method, the generated DataBindingComponent will have
* a getter to retrieve an instance of the BindingAdapter's class to use to call the method.
*/
@Target(ElementType.METHOD)
public @interface BindingAdapter {
/**
* @return The attributes associated with this binding adapter.
*/
String[] value();
/**
* Whether every attribute must be assigned a binding expression or if some
* can be absent. When this is false, the BindingAdapter will be called
* when at least one associated attribute has a binding expression. The attributes
* for which there was no binding expression (even a normal XML value) will
* cause the associated parameter receive the Java default value. Care must be
* taken to ensure that a default value is not confused with a valid XML value.
*
* @return whether or not every attribute must be assigned a binding expression. The default
* value is true.
*/
boolean requireAll() default true;
}
|
