public interface InverseBindingListener
android.databinding.InverseBindingListener |
由所有双向绑定实现的监听器在发生触发更改时得到通知。 例如,当对android:text有双向绑定时,将在布局的绑定类中生成一个InverseBindingListener
的实现。
private static class InverseListenerTextView implements InverseBindingListener { @Override public void onChange() { mObj.setTextValue(mTextView.getText()); } }
应使用BindingAdapter
分配事件侦听器。 例如, android:onTextChanged
将需要触发android:text
属性的事件侦听器。
@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 methods |
|
---|---|
abstract void |
onChange() 通知数据绑定系统该属性值已更改。 |
void onChange ()
通知数据绑定系统该属性值已更改。