使用@InverseBindingAdapter/AttrChanged进行Android Spinner双向绑定不起作用
我一直试图在Spinner上设置一个双向绑定。
有很多这样的例子,在网络上和堆栈溢出,但没有一个适合我。
这只是一个国家的微调,我已经为它定义一个国家适配器此方法:
@InverseBindingAdapter(attribute = "selectedCountry", event = "selectedCountryAttrChanged")
public static String bindCountryInverseAdapter(AppCompatSpinner pAppCompatSpinner) {
Object selectedItem = pAppCompatSpinner.getSelectedItem();
SpinnerAdapter adapter = pAppCompatSpinner.getAdapter();
if (adapter instanceof CountrySpinnerAdapter) {
return (String) selectedItem;
}
throw new UnsupportedOperationException("The adapter must be a CountrySpinnerAdapter");
}
@BindingAdapter(value = "selectedCountryAttrChanged", requireAll = false)
public static void bindCountryChanged(AppCompatSpinner pAppCompatSpinner, final InverseBindingListener newTextAttrChanged) {
AdapterView.OnItemSelectedListener listener = new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
newTextAttrChanged.onChange();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
newTextAttrChanged.onChange();
}
};
pAppCompatSpinner.setOnItemSelectedListener(listener);
}
@BindingAdapter("selectedCountry")
public static void bindCountryValue(AppCompatSpinner pAppCompatSpinner, String newSelectedValue) {
SpinnerAdapter adapter = pAppCompatSpinner.getAdapter();
if (adapter instanceof CountrySpinnerAdapter) {
((CountrySpinnerAdapter) adapter).bindSelectedValue(pAppCompatSpinner, newSelectedValue);
return;
}
throw new UnsupportedOperationException("The adapter must be a CountrySpinnerAdapter");
}
的bindCountryChanged方法不会被调用。
我也试过这个变体(以下其他例子):
@BindingAdapter(value = {"selectedCountry", "selectedCountryAttrChanged"}, requireAll = false)
public static void bindCountryValueChanged(AppCompatSpinner pAppCompatSpinner, String newSelectedValue, final InverseBindingListener newTextAttrChanged) {
AdapterView.OnItemSelectedListener listener = new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
newTextAttrChanged.onChange();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
newTextAttrChanged.onChange();
}
};
pAppCompatSpinner.setOnItemSelectedListener(listener);
}
这就是所谓的,但newTextAttrChanged总是空。
布局,结合部分:
<data>
<variable
name="customer"
type="my.package.CustomerBinding" />
</data>
而且小部件:
<android.support.v7.widget.AppCompatSpinner
android:id="@+id/editCountry"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:spinnerMode="dropdown"
app:adapter="@{customer.countrySpinnerAdapter}"
app:selectedCountry="@{customer.country}" />
country ID只是一个ObservableField<String>和countrySpinnerAdapter是国家的列表中BaseAdapter。
的Android gradle这个插件:
classpath 'com.android.tools.build:gradle:2.2.1'
工具版本:
buildToolsVersion "24.0.2"
当然,数据绑定启用:
dataBinding {
enabled = true
}
为什么newTextAttrChanged总是空/对BindingAdapter从来都不是calld?我究竟做错了什么?