Source code
package android.support.v7.internal.widget;
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build.VERSION;
import android.support.v4.widget.PopupWindowCompat;
import android.support.v7.appcompat.R;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewTreeObserver.OnScrollChangedListener;
import android.widget.PopupWindow;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;
public class AppCompatPopupWindow extends PopupWindow {
private static final boolean COMPAT_OVERLAP_ANCHOR = (VERSION.SDK_INT < 21);
private static final String TAG = "AppCompatPopupWindow";
private boolean mOverlapAnchor;
public AppCompatPopupWindow(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
TintTypedArray a = TintTypedArray.obtainStyledAttributes(context, attrs, R.styleable.PopupWindow, defStyleAttr, 0);
if (a.hasValue(R.styleable.PopupWindow_overlapAnchor)) {
setSupportOverlapAnchor(a.getBoolean(R.styleable.PopupWindow_overlapAnchor, false));
}
setBackgroundDrawable(a.getDrawable(R.styleable.PopupWindow_android_popupBackground));
a.recycle();
if (VERSION.SDK_INT < 14) {
wrapOnScrollChangedListener(this);
}
}
public void showAsDropDown(View anchor, int xoff, int yoff) {
if (COMPAT_OVERLAP_ANCHOR && this.mOverlapAnchor) {
yoff -= anchor.getHeight();
}
super.showAsDropDown(anchor, xoff, yoff);
}
@TargetApi(19)
public void showAsDropDown(View anchor, int xoff, int yoff, int gravity) {
if (COMPAT_OVERLAP_ANCHOR && this.mOverlapAnchor) {
yoff -= anchor.getHeight();
}
super.showAsDropDown(anchor, xoff, yoff, gravity);
}
public void update(View anchor, int xoff, int yoff, int width, int height) {
if (COMPAT_OVERLAP_ANCHOR && this.mOverlapAnchor) {
yoff -= anchor.getHeight();
}
super.update(anchor, xoff, yoff, width, height);
}
private static void wrapOnScrollChangedListener(final PopupWindow popup) {
try {
final Field fieldAnchor = PopupWindow.class.getDeclaredField("mAnchor");
fieldAnchor.setAccessible(true);
Field fieldListener = PopupWindow.class.getDeclaredField("mOnScrollChangedListener");
fieldListener.setAccessible(true);
final OnScrollChangedListener originalListener = (OnScrollChangedListener) fieldListener.get(popup);
fieldListener.set(popup, new OnScrollChangedListener() {
public void onScrollChanged() {
try {
WeakReference<View> mAnchor = (WeakReference) fieldAnchor.get(popup);
if (mAnchor != null && mAnchor.get() != null) {
originalListener.onScrollChanged();
}
} catch (IllegalAccessException e) {
}
}
});
} catch (Exception e) {
Log.d(TAG, "Exception while installing workaround OnScrollChangedListener", e);
}
}
public void setSupportOverlapAnchor(boolean overlapAnchor) {
if (COMPAT_OVERLAP_ANCHOR) {
this.mOverlapAnchor = overlapAnchor;
} else {
PopupWindowCompat.setOverlapAnchor(this, overlapAnchor);
}
}
public boolean getSupportOverlapAnchor() {
if (COMPAT_OVERLAP_ANCHOR) {
return this.mOverlapAnchor;
}
return PopupWindowCompat.getOverlapAnchor(this);
}
}