Allocate space above keyboard for candidates bar etc.

and fix key preview popups clipped for API level 28,
which is dumb (see <https://stackoverflow.com/q/52929466>)

Author: yawnoc

app/src/main/java/io/github/yawnoc/strokeinput/InputContainer.java

@@ -44,10 +44,12 @@
 
 /*
   A container that holds:
+    - Stroke sequence bar
     - Candidates bar
     - Keyboard
   TODO:
-    - Candidates
+    - Stroke sequence bar
+    - Candidates bar
 */
 public class InputContainer
   extends View
@@ -80,6 +82,7 @@ public class InputContainer
   private OnInputListener inputListener;
   private Keyboard keyboard;
   private Key[] keyArray;
+  private int touchableTopY;
 
   // Active key
   private Key activeKey;
@@ -226,6 +229,10 @@ public void setKeyboard(final Keyboard keyboard) {
     requestLayout();
   }
 
+  public int getTouchableTopY() {
+    return touchableTopY;
+  }
+  
   @SuppressLint("RtlHardcoded")
   public void showKeyPreviewPlane() {
 
@@ -300,24 +307,32 @@ public void onMeasure(
   {
     final int keyboardWidth;
     final int keyboardHeight;
+    final int height;
+    final int popupBufferZoneHeight;
 
     if (keyboard == null) {
       keyboardWidth = 0;
       keyboardHeight = 0;
+      height = 0;
+      popupBufferZoneHeight = 0;
+      touchableTopY = 0;
     }
     else {
       keyboardWidth = keyboard.getWidth();
       keyboardHeight = keyboard.getHeight();
+      height = keyboard.getParentInputContainerHeight();
+      popupBufferZoneHeight = keyboard.getPopupBufferZoneHeight();
+      touchableTopY = keyboard.getParentInputContainerTouchableTopY();
     }
 
     keyboardRectangle.set(
       0,
-      Keyboard.KEYBOARD_GUTTER_HEIGHT_PX,
+      popupBufferZoneHeight,
       keyboardWidth,
-      Keyboard.KEYBOARD_GUTTER_HEIGHT_PX + keyboardHeight
+      popupBufferZoneHeight + keyboardHeight
     );
 
-    setMeasuredDimension(keyboardWidth, keyboardHeight);
+    setMeasuredDimension(keyboardWidth, height);
   }
 
   @Override

app/src/main/java/io/github/yawnoc/strokeinput/Keyboard.java

@@ -25,6 +25,7 @@
 import android.content.res.TypedArray;
 import android.content.res.XmlResourceParser;
 import android.graphics.Color;
+import android.os.Build;
 import android.util.DisplayMetrics;
 import android.util.Log;
 import android.util.Xml;
@@ -36,12 +37,20 @@
 
 /*
   A container that holds rows of keys, to be declared in a layout XML.
+  It also determines the vertical placement of the stroke sequence bar
+  and the candidates bar, which are separate entities to be placed
+  above the keyboard (in the parent input container).
 */
 public class Keyboard {
 
-  private static final int DEFAULT_KEYBOARD_FILL_COLOUR = Color.BLACK;
+  private static final int STROKE_SEQUENCE_BAR_HEIGHT_DP = 24;
+  private final int strokeSequenceBarHeightPx;
+  private static final int CANDIDATES_BAR_HEIGHT_DP = 36;
+  private final int candidatesBarHeightPx;
   public static final int KEYBOARD_GUTTER_HEIGHT_PX = 1;
 
+  private static final int DEFAULT_KEYBOARD_FILL_COLOUR = Color.BLACK;
+  
   private static final float KEYBOARD_HEIGHT_MAX_FRACTION = 0.5f;
 
   private static final float DEFAULT_KEY_WIDTH_FRACTION = 0.1f;
@@ -62,6 +71,11 @@ public class Keyboard {
   private static final int DEFAULT_KEY_PREVIEW_MARGIN_Y_DP = 16;
   private final int defaultKeyPreviewMarginYPx;
 
+  // Parent input container properties
+  private int popupBufferZoneHeight;
+  private int parentInputContainerHeight;
+  private int parentInputContainerTouchableTopY;
+  
   // Keyboard properties
   private int width;
   private int height;
@@ -88,14 +102,23 @@ public class Keyboard {
   private final int screenWidth;
   private final int screenHeight;
 
-  public Keyboard(final Context context, final int layoutResourceId) {
-    
+  public Keyboard(
+    final Context context,
+    final int layoutResourceId,
+    final boolean isFullscreenMode
+  )
+  {
     final DisplayMetrics displayMetrics =
       context.getResources().getDisplayMetrics();
 
     screenWidth = displayMetrics.widthPixels;
     screenHeight = displayMetrics.heightPixels;
 
+    strokeSequenceBarHeightPx =
+      (int) Valuey.pxFromDp(STROKE_SEQUENCE_BAR_HEIGHT_DP, displayMetrics);
+    candidatesBarHeightPx =
+      (int) Valuey.pxFromDp(CANDIDATES_BAR_HEIGHT_DP, displayMetrics);
+    
     defaultKeyHeightPx =
       (int) Valuey.pxFromDp(DEFAULT_KEY_HEIGHT_DP, displayMetrics);
     defaultKeyBorderThicknessPx =
@@ -108,13 +131,25 @@ public Keyboard(final Context context, final int layoutResourceId) {
     keyList = new ArrayList<>();
 
     loadKeyboard(context, context.getResources().getXml(layoutResourceId));
-    adjustKeyboardVertically();
+    adjustKeyboardVertically(isFullscreenMode);
   }
 
   public List<Key> getKeyList() {
     return keyList;
   }
 
+  public int getPopupBufferZoneHeight() {
+    return popupBufferZoneHeight;
+  }
+  
+  public int getParentInputContainerHeight() {
+    return parentInputContainerHeight;
+  }
+  
+  public int getParentInputContainerTouchableTopY() {
+    return parentInputContainerTouchableTopY;
+  }
+  
   public int getWidth() {
     return width;
   }
@@ -142,7 +177,7 @@ private void loadKeyboard(
       boolean inRow = false;
 
       int x = 0;
-      int y = 0;
+      int y = KEYBOARD_GUTTER_HEIGHT_PX;
       Key key = null;
       Row row = null;
 
@@ -200,20 +235,42 @@ else if (inRow) {
     }
   }
 
-  private void adjustKeyboardVertically() {
+  private void adjustKeyboardVertically(final boolean isFullscreenMode) {
 
     final float keyboardHeightCorrectionFactor =
       Math.min(1, KEYBOARD_HEIGHT_MAX_FRACTION * screenHeight / height);
 
     for (Key key : keyList) {
       key.y *= keyboardHeightCorrectionFactor;
-      key.y += KEYBOARD_GUTTER_HEIGHT_PX;
       key.height *= keyboardHeightCorrectionFactor;
       key.textOffsetY *= keyboardHeightCorrectionFactor;
       key.previewMarginY *= keyboardHeightCorrectionFactor;
     }
-    
     height *= keyboardHeightCorrectionFactor;
+    
+    if (Build.VERSION.SDK_INT == 28 && !isFullscreenMode) {
+      // API level 28 is dumb, see <https://stackoverflow.com/q/52929466>
+      int popupBufferZoneTopY =
+        -(strokeSequenceBarHeightPx + candidatesBarHeightPx);
+      for (Key key : keyList) {
+        final int keyPreviewHeight =
+          (int) (key.previewMagnification * key.height);
+        popupBufferZoneTopY = Math.min(
+          key.y - keyPreviewHeight - key.previewMarginY,
+          popupBufferZoneTopY
+        );
+      }
+      popupBufferZoneHeight = -popupBufferZoneTopY;
+    }
+    else {
+      popupBufferZoneHeight = candidatesBarHeightPx;
+    }
+    for (Key key : keyList) {
+      key.y += popupBufferZoneHeight;
+    }
+    parentInputContainerHeight = height + popupBufferZoneHeight;
+    parentInputContainerTouchableTopY =
+      Math.max(0, popupBufferZoneHeight - candidatesBarHeightPx);
   }
 
   private void parseKeyboardAttributes(

app/src/main/java/io/github/yawnoc/strokeinput/StrokeInputService.java

@@ -54,13 +54,13 @@ public View onCreateInputView() {
         getLayoutInflater().inflate(R.layout.input_container, null);
 
     strokesKeyboard =
-      new Keyboard(this, R.xml.keyboard_strokes);
+      new Keyboard(this, R.xml.keyboard_strokes, isFullscreenMode());
     strokesSymbolsKeyboard =
-      new Keyboard(this, R.xml.keyboard_strokes_symbols);
+      new Keyboard(this, R.xml.keyboard_strokes_symbols, isFullscreenMode());
     qwertyKeyboard =
-      new Keyboard(this, R.xml.keyboard_qwerty);
+      new Keyboard(this, R.xml.keyboard_qwerty, isFullscreenMode());
     qwertySymbolsKeyboard =
-      new Keyboard(this, R.xml.keyboard_qwerty_symbols);
+      new Keyboard(this, R.xml.keyboard_qwerty_symbols, isFullscreenMode());
 
     nameFromKeyboard = new HashMap<>();
     nameFromKeyboard.put(strokesKeyboard, "STROKES");
@@ -82,6 +82,17 @@ public void onStartInputView(EditorInfo editorInfo, boolean isRestarting) {
     inputContainer.showKeyPreviewPlane();
   }
 
+  @Override
+  public void onComputeInsets(InputMethodService.Insets insets) {
+    super.onComputeInsets(insets);
+    // API level 28 is dumb, see <https://stackoverflow.com/a/53326786>
+    final int touchableTopY = inputContainer.getTouchableTopY();
+    if (touchableTopY > 0) {
+      insets.visibleTopInsets = touchableTopY;
+      insets.contentTopInsets = touchableTopY;
+    }
+  }
+  
   @Override
   public void onKey(final String valueText) {