1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package android.databinding;
17 
18 import android.os.Parcel;
19 import android.os.Parcelable;
20 
21 import java.io.Serializable;
22 
23 /**
24  * An observable class that holds a primitive float.
25  * <p>
26  * Observable field classes may be used instead of creating an Observable object:
27  * <pre><code>public class MyDataObject {
28  *     public final ObservableFloat temperature = new ObservableFloat();
29  * }</code></pre>
30  * Fields of this type should be declared final because bindings only detect changes in the
31  * field's value, not of the field itself.
32  * <p>
33  * This class is parcelable and serializable but callbacks are ignored when the object is
34  * parcelled / serialized. Unless you add custom callbacks, this will not be an issue because
35  * data binding framework always re-registers callbacks when the view is bound.
36  */
37 public class ObservableFloat extends BaseObservable implements Parcelable, Serializable {
38     static final long serialVersionUID = 1L;
39     private float mValue;
40 
41     /**
42      * Creates an ObservableFloat with the given initial value.
43      *
44      * @param value the initial value for the ObservableFloat
45      */
ObservableFloat(float value)46     public ObservableFloat(float value) {
47         mValue = value;
48     }
49 
50     /**
51      * Creates an ObservableFloat with the initial value of <code>0f</code>.
52      */
ObservableFloat()53     public ObservableFloat() {
54     }
55 
56     /**
57      * @return the stored value.
58      */
get()59     public float get() {
60         return mValue;
61     }
62 
63     /**
64      * Set the stored value.
65      */
set(float value)66     public void set(float value) {
67         if (value != mValue) {
68             mValue = value;
69             notifyChange();
70         }
71     }
72 
73     @Override
describeContents()74     public int describeContents() {
75         return 0;
76     }
77 
78     @Override
writeToParcel(Parcel dest, int flags)79     public void writeToParcel(Parcel dest, int flags) {
80         dest.writeFloat(mValue);
81     }
82 
83     public static final Parcelable.Creator<ObservableFloat> CREATOR
84             = new Parcelable.Creator<ObservableFloat>() {
85 
86         @Override
87         public ObservableFloat createFromParcel(Parcel source) {
88             return new ObservableFloat(source.readFloat());
89         }
90 
91         @Override
92         public ObservableFloat[] newArray(int size) {
93             return new ObservableFloat[size];
94         }
95     };
96 }
97