在了解了不同分辨率的一些问题后，我决定使用相对大小。正如我所注意到的，可见状态和隐藏状态之间的差异约为30%。所以我决定用0.3代替128 PX。

我添加了这个类监听器来通知任何变化。

这是我的版本

import android.app.*;
import android.graphics.*;
import android.view.*;

public class SoftKeyboardState {
  public static final int HIDDEN = 0, VISIBLE = 1;
  private OnKeyboardStateChangedListener listener;
  private View decorView;

  public SoftKeyboardState(Activity activity) {
    this.decorView = activity.findViewById(android.R.id.content);
    initKeyboardListener();
  }

  private void initKeyboardListener() {
    decorView.getViewTreeObserver().addOnGlobalLayoutListener(
      new ViewTreeObserver.OnGlobalLayoutListener(){
        private final Rect windowVisibleDisplayFrame = new Rect();
        private int lastVisibleDecorViewHeight;

        @Override
        public void onGlobalLayout() {
          decorView.getWindowVisibleDisplayFrame(windowVisibleDisplayFrame);
          final int visibleDecorViewHeight = windowVisibleDisplayFrame.height();

          if (lastVisibleDecorViewHeight != 0) {
            if ((lastVisibleDecorViewHeight > visibleDecorViewHeight) && (lastVisibleDecorViewHeight / visibleDecorViewHeight >= 0.3f)) {
              // visible
              if (listener != null)listener.onKeyboardStateChanged(VISIBLE);
            } else if ((lastVisibleDecorViewHeight < visibleDecorViewHeight) && (visibleDecorViewHeight / lastVisibleDecorViewHeight >= 0.3f)) {
              // hidden
              if (listener != null)listener.onKeyboardStateChanged(HIDDEN);
            }
          }
          lastVisibleDecorViewHeight = visibleDecorViewHeight;
        }
      });
  }

  public void setOnKeyboardStateChangedListener(OnKeyboardStateChangedListener listener) {
    this.listener = listener;
  }

  public interface OnKeyboardStateChangedListener {
    public void onKeyboardStateChanged(int state);
  }
}

InputMethodManager有关于软键盘的信息。你从一个活动中获得它:

((InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE))

你可以摆弄一下，看看它能告诉你什么。你可以用它来显示或隐藏软输入…

我知道这是一篇老文章，但我认为这是我所知道的最简单的方法，我的测试设备是Nexus 5。我还没有在其他设备上尝试过。希望其他人会分享他们的方法，如果他们发现我的代码不好:)

public static boolean isKeyboardShown(Context context, View view) {
        if (context == null || view == null) {
            return false;
        }
        InputMethodManager imm = (InputMethodManager) context
                .getSystemService(Context.INPUT_METHOD_SERVICE);
        return imm.hideSoftInputFromWindow(view.getWindowToken(), 0); 
}

imm。hideSoftInputFromWindow返回布尔值。

谢谢,

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
    }

    ...
}

我花了一点时间才想明白……我运行它一些castexception，但发现你可以用类的名称替换layout.xml中的LinearLayout。

是这样的:

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/llMaster">

<com.ourshoppingnote.RelativeLayoutThatDetectsSoftKeyboard android:background="@drawable/metal_background"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:id="@+id/rlMaster" >
    <LinearLayout android:layout_width="fill_parent"
        android:layout_height="1dip" android:background="@drawable/line"></LinearLayout>

          ....

</com.ourshoppingnote.RelativeLayoutThatDetectsSoftKeyboard>    


</LinearLayout>

这样你就不会遇到任何演员问题。

．.． 如果你不想在每个页面上都这样做，我建议你使用“安卓版MasterPage”。点击这里查看链接: http://jnastase.alner.net/archive/2011/01/08/ldquomaster-pagesrdquo-in-android.aspx

参考@TacB0sS的回答，我在Kotlin中开发了一个类。希望这对你有所帮助。如果需要改进，请告诉我。

class KeyboardVisibilityObserver(val layRootContainer: View?, val keyboardVisibilityListener: KeyboardVisibilityListener?) {
    var isKeyboardOpen = false
        private set

    private var keyBoardObserver = object : ViewTreeObserver.OnGlobalLayoutListener {

        private val DefaultKeyboardDP = 100

        // Lollipop includes button bar in the root. Add height of button bar (48dp) to maxDiff
        private val EstimatedKeyboardDP = DefaultKeyboardDP + if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) 48 else 0

        private val r = Rect()

        override fun onGlobalLayout() {
            if (layRootContainer != null) {
                // Convert the dp to pixels.
                val estimatedKeyboardHeight = TypedValue
                        .applyDimension(TypedValue.COMPLEX_UNIT_DIP, EstimatedKeyboardDP.toFloat(), layRootContainer.resources.displayMetrics).toInt()

                // Conclude whether the keyboard is shown or not.
                layRootContainer.getWindowVisibleDisplayFrame(r)
                val heightDiff = layRootContainer.rootView.height - (r.bottom - r.top)
                val isShown = heightDiff >= estimatedKeyboardHeight

                if (isShown == isKeyboardOpen) {
                    //  Log.d("Keyboard state", "Ignoring global layout change...");
                    return
                }

                isKeyboardOpen = isShown

                keyboardVisibilityListener?.onKeyboardVisibilityChanged(isKeyboardOpen)
            }
        }
    }

    init {
        layRootContainer?.viewTreeObserver?.addOnGlobalLayoutListener(keyBoardObserver)
    }

    // call this in onDestroy
    fun removeObserver(){
        layRootContainer?.viewTreeObserver?.removeOnGlobalLayoutListener(keyBoardObserver)
    }

    interface KeyboardVisibilityListener {
        fun onKeyboardVisibilityChanged(isKeyboardOpen: Boolean)
    }
}