| /* |
| * 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; |
| } |