fix keyboard-height-aware layout in lollipop

fixes #3303
// FREEBIE

src/org/thoughtcrime/securesms/components/KeyboardAwareLinearLayout.java

@@ -21,15 +21,19 @@ import android.app.Activity;
 import android.content.Context;
 import android.graphics.Rect;
 import android.os.Build;
+import android.os.Build.VERSION_CODES;
 import android.preference.PreferenceManager;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.Surface;
+import android.view.View;
 import android.view.WindowManager;
 import android.widget.LinearLayout;
 
 import org.thoughtcrime.securesms.R;
 
+import java.lang.reflect.Field;
+
 /**
  * LinearLayout that, when a view container, will report back when it thinks a soft keyboard
  * has been opened and what its height would be.
@@ -61,7 +65,7 @@ public class KeyboardAwareLinearLayout extends LinearLayout {
     int res = getResources().getIdentifier("status_bar_height", "dimen", "android");
     int statusBarHeight = res > 0 ? getResources().getDimensionPixelSize(res) : 0;
 
-    final int availableHeight = this.getRootView().getHeight() - statusBarHeight;
+    final int availableHeight = this.getRootView().getHeight() - statusBarHeight - getViewInset();
     getWindowVisibleDisplayFrame(rect);
 
     final int keyboardHeight = availableHeight - (rect.bottom - rect.top);
@@ -73,6 +77,29 @@ public class KeyboardAwareLinearLayout extends LinearLayout {
     super.onMeasure(widthMeasureSpec, heightMeasureSpec);
   }
 
+  public int getViewInset() {
+    if (Build.VERSION.SDK_INT < VERSION_CODES.LOLLIPOP) {
+      return 0;
+    }
+
+    try {
+      Field attachInfoField = View.class.getDeclaredField("mAttachInfo");
+      attachInfoField.setAccessible(true);
+      Object attachInfo = attachInfoField.get(this);
+      if (attachInfo != null) {
+        Field stableInsetsField = attachInfo.getClass().getDeclaredField("mStableInsets");
+        stableInsetsField.setAccessible(true);
+        Rect insets = (Rect)stableInsetsField.get(attachInfo);
+        return insets.bottom;
+      }
+    } catch (NoSuchFieldException nsfe) {
+      Log.w(TAG, "field reflection error when measuring view inset", nsfe);
+    } catch (IllegalAccessException iae) {
+      Log.w(TAG, "access reflection error when measuring view inset", iae);
+    }
+    return 0;
+  }
+
   protected void onKeyboardShown(int keyboardHeight) {
     Log.w(TAG, "keyboard shown, height " + keyboardHeight);