編譯環境：gradle:3.2.0 

按照原始碼要求使用notifyPropertyChanged方法，仍一直報cannot find symbol BR in android data binding，重構什麼都沒效果。

原始碼：

/**
     * Notifies listeners that a specific property has changed. The getter for the property
     * that changes should be marked with {@link Bindable} to generate a field in
     * <code>BR</code> to be used as <code>fieldId</code>.
     *
     * @param fieldId The generated BR id for the Bindable field.
     */
    public void notifyPropertyChanged(int fieldId) {
        synchronized (this) {
            if (mCallbacks == null) {
                return;
            }
        }
        mCallbacks.notifyCallbacks(this, fieldId, null);
    }
 

在Stack Overflow上看到解決方案：

 在build.gradle（project：XXXX）檔案中加 classpath 'com.neenbedankt.gradle.plugins:android-apt:1.7'

試了一把還是沒效果。繼續看評論，一個哥們說：In case someone still has this problem. I solved this by invalidating the cache in Android Studio. And I'm using Android Studio 2 with API 23。

在試一把

file——>invalidate caches/restart...——>just restart   問題解決

如圖：

如圖：

 Stack Overflow ：https://stackoverflow.com/questions/30776466/cannot-find-symbol-br-in-android-data-binding/