我需要做一件非常简单的事情-找出软件键盘是否显示。这在Android中可行吗?
当前回答
这是我的解决方案,它很有效。而不是寻找像素大小,只是检查内容视图的高度是否改变:
// Scroll to the latest comment whenever the keyboard is shown
commentsContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
private int oldHeight;
@Override
public void onGlobalLayout() {
int newHeight = commentsContent.getMeasuredHeight();
if (newHeight < oldHeight) {
// Check for the keyboard showing in case the height difference
// is a result of orientation change
if (isSoftKeyboardShowing(CommentsActivity.this)) {
// Keyboard is showing so scroll to the latest comment
scrollToLatestComment();
}
}
oldHeight = newHeight;
}
});
public static boolean isSoftKeyboardShowing(Activity activity) {
InputMethodManager inputMethodManager = (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
return inputMethodManager.isActive();
}
其他回答
我的答案基本上与Kachi的答案相同,但我将它包装到一个很好的helper类中,以清理它在整个应用程序中的使用方式。
import android.app.Activity;
import android.app.Fragment;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
/**
* Detects Keyboard Status changes and fires events only once for each change
*/
public class KeyboardStatusDetector {
KeyboardVisibilityListener visibilityListener;
boolean keyboardVisible = false;
public void registerFragment(Fragment f) {
registerView(f.getView());
}
public void registerActivity(Activity a) {
registerView(a.getWindow().getDecorView().findViewById(android.R.id.content));
}
public KeyboardStatusDetector registerView(final View v) {
v.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
Rect r = new Rect();
v.getWindowVisibleDisplayFrame(r);
int heightDiff = v.getRootView().getHeight() - (r.bottom - r.top);
if (heightDiff > 100) { // if more than 100 pixels, its probably a keyboard...
/** Check this variable to debounce layout events */
if(!keyboardVisible) {
keyboardVisible = true;
if(visibilityListener != null) visibilityListener.onVisibilityChanged(true);
}
} else {
if(keyboardVisible) {
keyboardVisible = false;
if(visibilityListener != null) visibilityListener.onVisibilityChanged(false);
}
}
}
});
return this;
}
public KeyboardStatusDetector setVisibilityListener(KeyboardVisibilityListener listener) {
visibilityListener = listener;
return this;
}
public static interface KeyboardVisibilityListener {
public void onVisibilityChanged(boolean keyboardVisible);
}
}
你可以使用它来检测整个应用程序中的键盘变化,如下所示:
new KeyboardStatusDetector()
.registerFragment(fragment) //register to a fragment
.registerActivity(activity) //or register to an activity
.registerView(view) //or register to a view
.setVisibilityListener(new KeyboardVisibilityListener() {
@Override
public void onVisibilityChanged(boolean keyboardVisible) {
if(keyboardVisible) {
//Do stuff for keyboard visible
}else {
//Do stuff for keyboard hidden
}
}
});
注意:只使用一个“寄存器”调用。它们都是一样的,只是为了方便
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…
就计算机而言,这是永远的问题,但这个问题仍然令人难以置信地相关!
所以我把上面的答案结合起来,做了一些改进……
public interface OnKeyboardVisibilityListener {
void onVisibilityChanged(boolean visible);
}
public final void setKeyboardListener(final OnKeyboardVisibilityListener listener) {
final View activityRootView = ((ViewGroup) getActivity().findViewById(android.R.id.content)).getChildAt(0);
activityRootView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
private boolean wasOpened;
private final int DefaultKeyboardDP = 100;
// From @nathanielwolf answer... Lollipop includes button bar in the root. Add height of button bar (48dp) to maxDiff
private final int EstimatedKeyboardDP = DefaultKeyboardDP + (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? 48 : 0);
private final Rect r = new Rect();
@Override
public void onGlobalLayout() {
// Convert the dp to pixels.
int estimatedKeyboardHeight = (int) TypedValue
.applyDimension(TypedValue.COMPLEX_UNIT_DIP, EstimatedKeyboardDP, activityRootView.getResources().getDisplayMetrics());
// Conclude whether the keyboard is shown or not.
activityRootView.getWindowVisibleDisplayFrame(r);
int heightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
boolean isShown = heightDiff >= estimatedKeyboardHeight;
if (isShown == wasOpened) {
Log.d("Keyboard state", "Ignoring global layout change...");
return;
}
wasOpened = isShown;
listener.onVisibilityChanged(isShown);
}
});
}
对我有用:)
注意: 如果你注意到DefaultKeyboardDP不适合你的设备播放的值,并发表评论,让每个人都知道应该是什么值…最终我们将得到适合所有设备的正确值!
要了解更多细节,请查看Cyborg上的实现
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);
}
}
检查元素的高度是不可靠的,因为一些键盘,如WifiKeyboard的高度为零。
相反,您可以使用showSoftInput()和hideSoftInput()的回调结果来检查键盘的状态。完整的细节和示例代码在
https://rogerkeays.com/how-to-check-if-the-software-keyboard-is-shown-in-android
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