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
视图#setOnApplyWindowInsetsListener可以用来获得窗口insets回调
public void setOnApplyWindowInsetsListener(OnApplyWindowInsetsListener listener) {
getListenerInfo().mOnApplyWindowInsetsListener = listener;
}
//OnApplyWindowInsetsListener
public WindowInsets onApplyWindowInsets(View v, WindowInsets insets);
boolean keyboardVisible = insets.isVisible(WindowInsets.Type.ime())可以给出可见性状态。
其他回答
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
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
一些改进,以避免在高密度设备上错误地检测软键盘的可见性:
Threshold of height difference should be defined as 128 dp, not 128 pixels. Refer to Google design doc about Metrics and Grid, 48 dp is comfortable size for touch object and 32 dp is minimum for buttons. Generic soft keyboard should include 4 rows of key buttons, so minimum keyboard height should be: 32 dp * 4 = 128 dp, that means threshold size should transfer to pixels by multiply device density. For xxxhdpi devices (density 4), the soft keyboard height threshold should be 128 * 4 = 512 pixels. Height difference between root view and its visible area: root view height - status bar height - visible frame height = root view bottom - visible frame bottom, since status bar height equal to the top of root view visible frame. private final String TAG = "TextEditor"; private TextView mTextEditor; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_editor); mTextEditor = (TextView) findViewById(R.id.text_editor); mTextEditor.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { isKeyboardShown(mTextEditor.getRootView()); } }); } private boolean isKeyboardShown(View rootView) { /* 128dp = 32dp * 4, minimum button height 32dp and generic 4 rows soft keyboard */ final int SOFT_KEYBOARD_HEIGHT_DP_THRESHOLD = 128; Rect r = new Rect(); rootView.getWindowVisibleDisplayFrame(r); DisplayMetrics dm = rootView.getResources().getDisplayMetrics(); /* heightDiff = rootView height - status bar height (r.top) - visible frame height (r.bottom - r.top) */ int heightDiff = rootView.getBottom() - r.bottom; /* Threshold size: dp to pixels, multiply with display density */ boolean isKeyboardShown = heightDiff > SOFT_KEYBOARD_HEIGHT_DP_THRESHOLD * dm.density; Log.d(TAG, "isKeyboardShown ? " + isKeyboardShown + ", heightDiff:" + heightDiff + ", density:" + dm.density + "root view height:" + rootView.getHeight() + ", rect:" + r); return isKeyboardShown; }
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…
我知道如何准确地确定键盘是否隐藏。
public int getStatusBarHeight() {
int result = 0;
int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
if (resourceId > 0) {
result = getResources().getDimensionPixelSize(resourceId);
}
return result;
}
public int getNavigationBarHeight() {
int result = 0;
int resourceId = getResources().getIdentifier("navigation_bar_height", "dimen", "android");
if (resourceId > 0) {
result = getResources().getDimensionPixelSize(resourceId);
}
return result;
}
public boolean isKeyboardHidden() {
int delta = mRootView.getRootView().getHeight() - mRootView.getHeight() - getNavigationBarHeight() - getStatusBarHeight()
- getSupportActionBar().getHeight();
return delta <= 0;
}
这适用于平板电脑。当导航栏水平显示时。
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