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 java.lang.annotation.ElementType; 19 import java.lang.annotation.Target; 20 21 /** 22 * InverseBindingMethod is used to identify how to listen for changes to a View property and which 23 * getter method to call. InverseBindingMethod should be associated with any class as part of 24 * {@link InverseBindingMethods}. 25 * <p> 26 * <pre> 27 * @InverseBindingMethods({@InverseBindingMethod( 28 * type = android.widget.TextView.class, 29 * attribute = "android:text", 30 * event = "android:textAttrChanged", 31 * method = "getText")}) 32 * public class MyTextViewBindingAdapters { ... } 33 * </pre> 34 * <p> 35 * <code>method</code> is optional. If it isn't provided, the attribute name is used to 36 * find the method name, either prefixing with "is" or "get". For the attribute 37 * <code>android:text</code>, data binding will search for a 38 * <code>public CharSequence getText()</code> method on {@link android.widget.TextView}. 39 * <p> 40 * <code>event</code> is optional. If it isn't provided, the event name is assigned the 41 * attribute name suffixed with <code>AttrChanged</code>. For the <code>android:text</code> 42 * attribute, the default event name would be <code>android:textAttrChanged</code>. The event 43 * should be set using a {@link BindingAdapter}. For example: 44 * <pre> 45 * @BindingAdapter(value = {"android:beforeTextChanged", "android:onTextChanged", 46 * "android:afterTextChanged", "android:textAttrChanged"}, 47 * requireAll = false) 48 * public static void setTextWatcher(TextView view, final BeforeTextChanged before, 49 * final OnTextChanged on, final AfterTextChanged after, 50 * final InverseBindingListener textAttrChanged) { 51 * TextWatcher newValue = new TextWatcher() { 52 * ... 53 * @Override 54 * public void onTextChanged(CharSequence s, int start, int before, int count) { 55 * if (on != null) { 56 * on.onTextChanged(s, start, before, count); 57 * } 58 * if (textAttrChanged != null) { 59 * textAttrChanged.onChange(); 60 * } 61 * } 62 * } 63 * TextWatcher oldValue = ListenerUtil.trackListener(view, newValue, R.id.textWatcher); 64 * if (oldValue != null) { 65 * view.removeTextChangedListener(oldValue); 66 * } 67 * view.addTextChangedListener(newValue); 68 * } 69 * </pre> 70 * 71 * @see InverseBindingAdapter 72 * @see InverseBindingListener 73 */ 74 @Target(ElementType.ANNOTATION_TYPE) 75 public @interface InverseBindingMethod { 76 77 /** 78 * The View type that is associated with the attribute. 79 */ type()80 Class type(); 81 82 /** 83 * The attribute that supports two-way binding. 84 */ attribute()85 String attribute(); 86 87 /** 88 * The event used to notify the data binding system that the attribute value has changed. 89 * Defaults to attribute() + "AttrChanged" 90 */ event()91 String event() default ""; 92 93 /** 94 * The getter method to retrieve the attribute value from the View. The default is 95 * the bean method name based on the attribute name. 96 */ method()97 String method() default ""; 98 } 99