你可以通过使用活动的decorView来观察软键盘的隐藏。

public final class SoftKeyboardUtil {
    public static final String TAG = "SoftKeyboardUtil";
    public static void observeSoftKeyBoard(Activity activity , final OnSoftKeyBoardHideListener listener){
        final View decorView = activity.getWindow().getDecorView();
        decorView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                Rect rect = new Rect();
                decorView.getWindowVisibleDisplayFrame(rect);
                int displayHight = rect.bottom - rect.top;
                int hight = decorView.getHeight();
                boolean hide = (double)displayHight / hight > 0.8 ;
                if(Log.isLoggable(TAG, Log.DEBUG)){
                    Log.d(TAG ,"DecorView display hight = "+displayHight);
                    Log.d(TAG ,"DecorView hight = "+ hight);
                    Log.d(TAG, "softkeyboard visible = " + !hide);
                }

                listener.onSoftKeyBoardVisible(!hide);

            }
        });
    }



    public interface OnSoftKeyBoardHideListener{
        void onSoftKeyBoardVisible(boolean visible);
    }
}

而不是假设差异编码，我做了这样的事情，因为我在我的应用程序中有菜单选项。

final View root= findViewById(R.id.myrootview); 
root.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
    public void onGlobalLayout() {
        int heightDiff = root.getRootView().getHeight() - root.getHeight();

        Rect rectgle= new Rect();
        Window window= getWindow();
        window.getDecorView().getWindowVisibleDisplayFrame(rectgle);
        int contentViewTop=                     
          window.findViewById(Window.ID_ANDROID_CONTENT).getTop();
        if(heightDiff <= contentViewTop){
            //Soft KeyBoard Hidden
        }else{
            //Soft KeyBoard Shown
        }
     }
});

我使用了与鲁班的答案略有不同的答案，事实证明在某些情况下更有帮助，特别是在使用高分辨率设备时。

final View activityRootView = findViewById(android.R.id.content);
activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(
        new OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                int heightView = activityRootView.getHeight();
                int widthView = activityRootView.getWidth();
                if (1.0 * widthView / heightView > 3) {
                    //Make changes for Keyboard not visible
                } else {
                    //Make changes for keyboard visible
                }
            }
        });

你可以试试这个，对我来说很管用:

InputMethodManager imm = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);

if (imm.isAcceptingText()) {
    //Software Keyboard was shown..
} else {
    //Software Keyboard was not shown..
}

Reuben Scratton的新答案(计算HeightDiff int HeightDiff = activityRootView.getRootView().getHeight() - activityRootView.getHeight();)如果您设置半透明状态栏模式，将无法在活动中工作。

如果你使用半透明状态栏，activityRootView.getHeight()将永远不会改变软键盘是否可见。它将始终返回活动和状态栏的高度。

例如，Nexus 4, Android 5.0.1，将Android:windowTranslucentStatus设置为true，它将永远返回1184，即使ime已经打开。如果你设置android:windowTranslucentStatus为false，它将正确返回高度，如果ime不可见，它将返回1134(不包括状态栏)。关闭ime，它可能会返回5xx(取决于ime的高度)

我不知道这是否是一个bug，我已经尝试了4.4.4和5.0.1，结果是一样的。

所以，到目前为止，第二个最被认可的答案，Kachi的解决方案将是最安全的方法来计算ime的高度。以下是一份复印件:

final View activityRootView = findViewById(R.id.activityRoot);
activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new        OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
Rect r = new Rect();
//r will be populated with the coordinates of your view that area still visible.
activityRootView.getWindowVisibleDisplayFrame(r);

int heightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
if (heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
    ... do something here
    }
 }
}); 

这个解决方案可能会重新打开键盘，但它是有效的。

InputMethodManager inputManager = ( (InputMethodManager) this.getSystemService(Context.INPUT_METHOD_SERVICE) );

private boolean isKeyboardShowing() {

    boolean isKeyboardShowing = inputManager.hideSoftInputFromWindow(irrelevantView.getWindowToken(), 0);
    if (isKeyboardShowing) {
        inputManager.showSoftInput(this.getCurrentFocus(), 0);
    }
    return isKeyboardShowing;
}