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.annotation;
17 
18 import static java.lang.annotation.ElementType.CONSTRUCTOR;
19 import static java.lang.annotation.ElementType.METHOD;
20 import static java.lang.annotation.ElementType.PARAMETER;
21 import static java.lang.annotation.ElementType.TYPE;
22 import static java.lang.annotation.RetentionPolicy.SOURCE;
23 
24 import android.os.Looper;
25 
26 import java.lang.annotation.Retention;
27 import java.lang.annotation.Target;
28 
29 /**
30  * Denotes that the annotated method or constructor should only be called on the
31  * UI thread. If the annotated element is a class, then all methods in the class
32  * should be called on the UI thread.
33  * <p>
34  * Example:
35  *
36  * <pre>
37  * <code>
38  *  &#64;UiThread
39  *  public abstract void setText(@NonNull String text) { ... }
40  * </code>
41  * </pre>
42  *
43  * @memberDoc This method must be called on the thread that originally created
44  *            this UI element. This is typically the
45  *            {@linkplain Looper#getMainLooper() main thread} of your app.
46  * @hide
47  */
48 @Retention(SOURCE)
49 @Target({METHOD,CONSTRUCTOR,TYPE,PARAMETER})
50 public @interface UiThread {
51 }
52