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
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)
}
}
其他回答
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
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;
}
}
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();
}
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…
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
}
...
}
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