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 androidx.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.CLASS; 23 24 import java.lang.annotation.Documented; 25 import java.lang.annotation.Retention; 26 import java.lang.annotation.Target; 27 28 /** 29 * Denotes that the annotated method or constructor should only be called on the UI thread. 30 * If the annotated element is a class, then all methods in the class should be called 31 * on the UI thread. 32 * <p> 33 * Example: 34 * <pre><code> 35 * @UiThread 36 * 37 * public abstract void setText(@NonNull String text) { ... } 38 * </code></pre> 39 * 40 * <p class="note"><b>Note:</b> Ordinarily, an app's UI thread is also the main 41 * thread. However, However, under special circumstances, an app's UI thread 42 * might not be its main thread; for more information, see 43 * <a href="/studio/write/annotations.html#thread-annotations">Thread 44 * annotations</a>. 45 * 46 * @see androidx.annotation.MainThread 47 */ 48 @Documented 49 @Retention(CLASS) 50 @Target({METHOD,CONSTRUCTOR,TYPE,PARAMETER}) 51 public @interface UiThread { 52 } 53