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
希望这能帮助到大家。
Reuben Scratton给出的新答案非常棒,而且非常有效,但它只在你将windowSoftInputMode设置为adjuststresize时才有效。如果你将它设置为adjustPan,使用他的代码片段仍然无法检测键盘是否可见。为了解决这个问题,我对上面的代码做了微小的修改。
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.height();
if (heightDiff > 0.25*activityRootView.getRootView().getHeight()) { // if more than 25% of the screen, its probably a keyboard...
... do something here
}
}
});
其他回答
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
}
...
}
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
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 Rect r = new Rect();
@Override
public void onGlobalLayout() {
activityRootView.getWindowVisibleDisplayFrame(r);
int heightDiff = activityRootView.getRootView().getHeight() - (r.bottom - r.top);
boolean isOpen = heightDiff > 100;
if (isOpen == wasOpened) {
logDebug("Ignoring global layout change...");
return;
}
wasOpened = isOpen;
listener.onVisibilityChanged(isOpen);
}
});
}
这对我很管用。
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
}
}
});
这些解决方案都不适用于棒棒糖。在Lollipop activityRootView.getRootView(). getheight()包含按钮栏的高度,而测量视图则不包含。我已经采用了上面最好/最简单的解决方案来处理棒棒糖。
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);
Resources res = getResources();
// The status bar is 25dp, use 50dp for assurance
float maxDiff =
TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, res.getDisplayMetrics());
//Lollipop includes button bar in the root. Add height of button bar (48dp) to maxDiff
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
float buttonBarHeight =
TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 48, res.getDisplayMetrics());
maxDiff += buttonBarHeight;
}
if (heightDiff > maxDiff) { // if more than 100 pixels, its probably a keyboard...
...do something here
}
}
});
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