2012年1月25日新增答案

写了下面的答案后，有人告诉我ViewTreeObserver和其他api的存在，这些api从版本1开始就潜伏在SDK中。

而不是需要一个自定义的布局类型，一个更简单的解决方案是给你的活动的根视图一个已知的ID，比如@+ ID /activityRoot，钩子一个GlobalLayoutListener到ViewTreeObserver，并从那里计算你的活动的视图根和窗口大小之间的大小差:

final View activityRootView = findViewById(R.id.activityRoot);
activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        int heightDiff = activityRootView.getRootView().getHeight() - activityRootView.getHeight();
        if (heightDiff > dpToPx(this, 200)) { // if more than 200 dp, it's probably a keyboard...
            // ... do something here
        }
     }
});

使用一个实用程序，如:

public static float dpToPx(Context context, float valueInDp) {
    DisplayMetrics metrics = context.getResources().getDisplayMetrics();
    return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, valueInDp, metrics);
}

简单!

注意: 你的应用程序必须在Android Manifest中设置这个标志Android:windowSoftInputMode=" adjuststresize "否则上述解决方案将无法工作。

原来的答案

是的，这是可能的，但它比应该的要难得多。

如果我需要关心键盘何时出现和消失(这是相当经常的)，那么我所做的是自定义我的顶级布局类为一个覆盖onMeasure()。基本逻辑是，如果布局发现自己填充的面积明显小于窗口的总面积，那么可能显示了软键盘。

import android.app.Activity;
import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.widget.LinearLayout;

/*
 * LinearLayoutThatDetectsSoftKeyboard - a variant of LinearLayout that can detect when 
 * the soft keyboard is shown and hidden (something Android can't tell you, weirdly). 
 */

public class LinearLayoutThatDetectsSoftKeyboard extends LinearLayout {

    public LinearLayoutThatDetectsSoftKeyboard(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public interface Listener {
        public void onSoftKeyboardShown(boolean isShowing);
    }
    private Listener listener;
    public void setListener(Listener listener) {
        this.listener = listener;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int height = MeasureSpec.getSize(heightMeasureSpec);
        Activity activity = (Activity)getContext();
        Rect rect = new Rect();
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(rect);
        int statusBarHeight = rect.top;
        int screenHeight = activity.getWindowManager().getDefaultDisplay().getHeight();
        int diff = (screenHeight - statusBarHeight) - height;
        if (listener != null) {
            listener.onSoftKeyboardShown(diff>128); // assume all soft keyboards are at least 128 pixels high
        }
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);       
    }

    }

然后在活动课上…

public class MyActivity extends Activity implements LinearLayoutThatDetectsSoftKeyboard.Listener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ...
        LinearLayoutThatDetectsSoftKeyboard mainLayout = (LinearLayoutThatDetectsSoftKeyboard)findViewById(R.id.main);
        mainLayout.setListener(this);
        ...
    }


    @Override
    public void onSoftKeyboardShown(boolean isShowing) {
        // do whatever you need to do here
    }

    ...
}

if (keyopen())
{
                InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
                imm.toggleSoftInput(InputMethodManager.HIDE_IMPLICIT_ONLY,0);            
}

上面的函数是我用来检查键盘是否可见的。如果是，那我就关上。

下面显示了所需的两种方法。

首先，在onCreate中定义可工作的窗口高度。

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

//  add to onCreate method
    Rect rectgle= new Rect();
    Window window= getWindow();
    window.getDecorView().getWindowVisibleDisplayFrame(rectgle);
    sheight= rectgle.bottom;
//

} 

然后，添加一个布尔方法来获取该实例的窗口高度。如果它与原来的不匹配(假设您没有在此过程中更改它……)，那么键盘是打开的。

public boolean keyopen()
{
    Rect rectgle= new Rect();
    Window window= getWindow();
    window.getDecorView().getWindowVisibleDisplayFrame(rectgle);
    int curheight= rectgle.bottom;

    if (curheight!=sheight)
    {
        return true;
    }
    else
    {
        return false;
    }
}

Frotz !

抱歉回答晚了，但我已经创建了一个小的帮助类来处理打开/关闭事件，通知侦听器和其他有用的东西，可能有人会发现它有帮助:

import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver;

import java.util.LinkedList;
import java.util.List;

public class SoftKeyboardStateWatcher implements ViewTreeObserver.OnGlobalLayoutListener {

    public interface SoftKeyboardStateListener {
        void onSoftKeyboardOpened(int keyboardHeightInPx);
        void onSoftKeyboardClosed();
    }

    private final List<SoftKeyboardStateListener> listeners = new LinkedList<SoftKeyboardStateListener>();
    private final View activityRootView;
    private int        lastSoftKeyboardHeightInPx;
    private boolean    isSoftKeyboardOpened;

    public SoftKeyboardStateWatcher(View activityRootView) {
        this(activityRootView, false);
    }

    public SoftKeyboardStateWatcher(View activityRootView, boolean isSoftKeyboardOpened) {
        this.activityRootView     = activityRootView;
        this.isSoftKeyboardOpened = isSoftKeyboardOpened;
        activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(this);
    }

    @Override
    public void onGlobalLayout() {
        final Rect r = new Rect();
        //r will be populated with the coordinates of your view that area still visible.
        activityRootView.getWindowVisibleDisplayFrame(r);

        final int heightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
        if (!isSoftKeyboardOpened && heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
            isSoftKeyboardOpened = true;
            notifyOnSoftKeyboardOpened(heightDiff);
        } else if (isSoftKeyboardOpened && heightDiff < 100) {
            isSoftKeyboardOpened = false;
            notifyOnSoftKeyboardClosed();
        }
    }

    public void setIsSoftKeyboardOpened(boolean isSoftKeyboardOpened) {
        this.isSoftKeyboardOpened = isSoftKeyboardOpened;
    }

    public boolean isSoftKeyboardOpened() {
        return isSoftKeyboardOpened;
    }

    /**
     * Default value is zero {@code 0}.
     *
     * @return last saved keyboard height in px
     */
    public int getLastSoftKeyboardHeightInPx() {
        return lastSoftKeyboardHeightInPx;
    }

    public void addSoftKeyboardStateListener(SoftKeyboardStateListener listener) {
        listeners.add(listener);
    }

    public void removeSoftKeyboardStateListener(SoftKeyboardStateListener listener) {
        listeners.remove(listener);
    }

    private void notifyOnSoftKeyboardOpened(int keyboardHeightInPx) {
        this.lastSoftKeyboardHeightInPx = keyboardHeightInPx;

        for (SoftKeyboardStateListener listener : listeners) {
            if (listener != null) {
                listener.onSoftKeyboardOpened(keyboardHeightInPx);
            }
        }
    }

    private void notifyOnSoftKeyboardClosed() {
        for (SoftKeyboardStateListener listener : listeners) {
            if (listener != null) {
                listener.onSoftKeyboardClosed();
            }
        }
    }
}

使用的例子:

final SoftKeyboardStateWatcher softKeyboardStateWatcher 
    = new SoftKeyboardStateWatcher(findViewById(R.id.activity_main_layout);

// Add listener
softKeyboardStateWatcher.addSoftKeyboardStateListener(...);
// then just handle callbacks

这个想法是，如果你需要隐藏你的键盘，同时检查软输入状态，使用以下解决方案:

public boolean hideSoftInput() {
    InputMethodManager imm = (InputMethodManager) getSystemService(Activity.INPUT_METHOD_SERVICE);
    return imm.hideSoftInputFromWindow(mViewPager.getWindowToken(), 0);
}

如果在隐藏之前显示键盘，则此方法返回true。

我认为这个方法将帮助你找出是键盘是可见的或不。

 public Boolean isSoftKeyBoardVisible(){
    InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);

    if (imm.isAcceptingText()) {
        Log.d(TAG,"Software Keyboard was shown");
        return true;
    } else {
        Log.d(TAG,"Software Keyboard was not shown");
        return false;
    }

}

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
                }
            }
        });