/*
* 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;
/**
* A listener implemented by all two-way bindings to be notified when a triggering change happens.
* For example, when there is a two-way binding for android:text, an implementation of
* InverseBindingListener
will be generated in the layout's binding class.
*
* private static class InverseListenerTextView implements InverseBindingListener { * @Override * public void onChange() { * mObj.setTextValue(mTextView.getText()); * } * } **
* A {@link BindingAdapter} should be used to assign the event listener.
* For example, android:onTextChanged
will need to trigger the event listener
* for the android:text
attribute.
*
* @InverseBindingAdapter(attribute = "android:text", event = "android:textAttrChanged") * public static void captureTextValue(TextView view, ObservableField<CharSequence> value) { * CharSequence newValue = view.getText(); * CharSequence oldValue = value.get(); * if (oldValue == null) { * value.set(newValue); * } else if (!contentEquals(newValue, oldValue)) { * value.set(newValue); * } * } * @BindingAdapter(value = {"android:beforeTextChanged", "android:onTextChanged", * "android:afterTextChanged", "android:textAttrChanged"}, * requireAll = false) * public static void setTextWatcher(TextView view, final BeforeTextChanged before, * final OnTextChanged on, final AfterTextChanged after, * final InverseBindingListener textAttrChanged) { * TextWatcher newValue = new TextWatcher() { * ... * @Override * public void onTextChanged(CharSequence s, int start, int before, int count) { * if (on != null) { * on.onTextChanged(s, start, before, count); * } * if (textAttrChanged != null) { * textAttrChanged.onChange(); * } * } * } * TextWatcher oldValue = ListenerUtil.trackListener(view, newValue, R.id.textWatcher); * if (oldValue != null) { * view.removeTextChangedListener(oldValue); * } * view.addTextChangedListener(newValue); * } **/ public interface InverseBindingListener { /** * Notifies the data binding system that the attribute value has changed. */ void onChange(); }