Android视图中的getOnClickListener()

Question

我需要Android中的Views的getOnClickListener().这样我就可以为我的视图分配一个临时的OnClickListener.我想这样使用它:

private View.OnClickListener oldListener;

public void assignTempListener(View view) {
    oldListener = view.getOnClickListener(); // doesn't exist

    view.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // some code

            v.setOnClickListener(oldListener);
        }
    });
}

问题是这个功能不存在.我也无法从View继承创建此方法,因为所有类型的视图都可以传递给assignTempListener.还有其他方法可以使用它吗？

编辑:在我的代码中犯了一个小错误.

Answer 1

你可以用...... 反思来做到这一点.*击鼓*

这条路线充满了危险.

我不推荐它,因为类的内部结构可以随时改变,但是如果真的不可避免的话,这就是你目前如何能够在Android 4.2.2中做到这一点:

/**
 * Returns the current View.OnClickListener for the given View
 * @param view the View whose click listener to retrieve
 * @return the View.OnClickListener attached to the view; null if it could not be retrieved
 */
public View.OnClickListener getOnClickListener(View view) {
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
        return getOnClickListenerV14(view);
    } else {
        return getOnClickListenerV(view);
    }
}

//Used for APIs lower than ICS (API 14)
private View.OnClickListener getOnClickListenerV(View view) {
    View.OnClickListener retrievedListener = null;
    String viewStr = "android.view.View";
    Field field;

    try {
        field = Class.forName(viewStr).getDeclaredField("mOnClickListener");
        retrievedListener = (View.OnClickListener) field.get(view);
    } catch (NoSuchFieldException ex) {
        Log.e("Reflection", "No Such Field.");
    } catch (IllegalAccessException ex) {
        Log.e("Reflection", "Illegal Access.");
    } catch (ClassNotFoundException ex) {
        Log.e("Reflection", "Class Not Found.");
    }

    return retrievedListener;
}

//Used for new ListenerInfo class structure used beginning with API 14 (ICS)
private View.OnClickListener getOnClickListenerV14(View view) {
    View.OnClickListener retrievedListener = null;
    String viewStr = "android.view.View";
    String lInfoStr = "android.view.View$ListenerInfo";

    try {
        Field listenerField = Class.forName(viewStr).getDeclaredField("mListenerInfo");
        Object listenerInfo = null;

        if (listenerField != null) {
            listenerField.setAccessible(true);
            listenerInfo = listenerField.get(view);
        }

        Field clickListenerField = Class.forName(lInfoStr).getDeclaredField("mOnClickListener");

        if (clickListenerField != null && listenerInfo != null) {
            retrievedListener = (View.OnClickListener) clickListenerField.get(listenerInfo);
        }
    } catch (NoSuchFieldException ex) {
        Log.e("Reflection", "No Such Field.");
    } catch (IllegalAccessException ex) {
        Log.e("Reflection", "Illegal Access.");
    } catch (ClassNotFoundException ex) {
        Log.e("Reflection", "Class Not Found.");
    }

    return retrievedListener;
}

Answer 2

您可以覆盖该类并为您的视图声明一个 onClicklistener 并为 onClickListener 字段编写 setter 和 getter：

public class SAutoBgButton extends ImageButton {

  public View.OnClickListener mOnClickListener;

  @Override
  public void setOnClickListener(OnClickListener l) {
    super.setOnClickListener(l);
    mOnClickListener = l;
  }
  public OnClickListener getmOnClickListener() {
    return mOnClickListener;
  }
}