java如何“强制转换”到泛型对象并使用泛型参数执行方法

Question

我有一个类，在请求时初始化一些GUI组件：

public class ComponentInitializer<T extends View>

public abstract void initialize(T object);

下面是初始化所有组件的代码段：

private <T extends View> void initComponents(View view) {
    // ArrayList<Component<? extends View>> this.componentInitializers
    for (ComponentInitializer<? extends View> initializer : this.componentInitializers) {
        View object = view.findViewById(initializer.getResourceId());

        if (object instanceof CheckBox) {
            ((ComponentInitializer<CheckBox>) initializer).initialize((CheckBox) object);
        }
        else if (object instanceof RadioButton) {
            ((ComponentInitializer<RadioButton>) initializer).initialize((RadioButton) object);
        }
        else if (object instanceof EditText) {
            ((ComponentInitializer<EditText>) initializer).initialize((EditText) object);
        }
    }
}

这是可行的；我测试过了

但是。。。有许多对象扩展安卓.view.View，我懒得为每个扩展View的对象创建代码块

else if (object instanceof ObjectExtendingView) {
    ((ComponentInitializer<ObjectExtendingView>) initializer).initialize((ObjectExtendingView) object);
}

是否有可能将代码段简化为一元语句，如下所示：

for (ComponentInitializer<? extends View> initializer : this.componentInitializers) {
    initializer.initialize(object); // Maybe with some casts
}

如果是，如何进行？如果不是，解决办法是什么

Answer 1

像这样的怎么样：

private void initComponents(View view) {
    for (ComponentInitializer<? extends View> initializer : this.componentInitializers) {
        helper(initializer, view);
    }
}

private static <T extends View> void helper(ComponentInitializer<T> initializer, View view) {
        T object = (T)view.findViewById(initializer.getResourceId());
        initializer.initialize(object);
}

Answer 2

知道T扩展了View，您可以安全地将对象强制转换为T。然后将调用相应的方法。这应该起作用：

private <T extends View> void initComponents(T view) {
    for (ComponentInitializer<? extends View> initializer : this.componentInitializers) {
        T object = (T) view.findViewById(initializer.getResourceId());
        if (object != null) {
            ((ComponentInitializer<T>) initializer).initialize((T) object);
        }
    }
}