NEW ANSWER 添加于2012年1月25日
自从写下以下答案以来，有人让我了解到ViewTreeObserver和朋友，自版本1以来一直潜伏在SDK中的API。
不需要自定义Layout类型，一种更简单的解决方案是为活动的根视图提供一个已知的ID，例如@+id/activityRoot，将GlobalLayoutListener挂接到ViewTreeObserver中，然后从中计算活动的视图根与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
}
}
});
使用实用程序，例如：
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：
您的应用程序必须在Android Manifest中设置此标志，android:windowSoftInputMode="adjustResize"否则以上解决方案将不起作用。
原始答案
是的，这是可能的，但它比应做的要难得多。
如果我需要关心键盘何时出现和消失（这是很常见的），那么我要做的就是将顶层布局类自定义为覆盖onMeasure()。基本逻辑是，如果布局发现自己填充的内容明显少于窗口的总面积，则可能显示软键盘。
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);
}
}
然后在您的Activity类中...
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
}
...
}