fhucho fhucho - 6 months ago 13
Android Question

How to check visibility of software keyboard in Android?

I need to do a very simple thing - find out if the software keyboard is shown. Is this possible in Android?

Answer

NEW ANSWER added Jan 25th 2012

Since writing the below answer, someone clued me in to the existence of ViewTreeObserver and friends, APIs which have been lurking in the SDK since version 1.

Rather than requiring a custom Layout type, a much simpler solution is to give your activity's root view a known ID, say '@+id/activityRoot', hook a GlobalLayoutListener into the ViewTreeObserver, and from there calculate the size diff between your activity's view root and the window size:

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 > 100) { // if more than 100 pixels, its probably a keyboard...
            ... do something here
        }
     }
});

Easy!

Note: Your application must set this flag in Android Manifest android:windowSoftInputMode="adjustResize" otherwise above solution will not work.

ORIGINAL ANSWER

Yes it's possible, but it's far harder than it ought to be.

If I need to care about when the keyboard appears and disappears (which is quite often) then what I do is customize my top-level layout class into one which overrides onMeasure(). The basic logic is that if the layout finds itself filling significantly less than the total area of the window, then a soft keyboard is probably showing.

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);       
    }

    }

Then in your Activity class...

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
    }

    ...
}