support repeating keyevents for emoji backspace

Fixes #2945
Closes #2988

// FREEBIE

res/layout/emoji_drawer.xml

@@ -16,13 +16,14 @@
                                           android:layout_width="0dp"
                                           android:layout_height="45dp" />
 
-        <ImageButton android:id="@+id/backspace"
-                     android:src="@drawable/ic_emoji_backspace"
-                     android:background="@color/emoji_tab_underline"
-                     android:paddingLeft="@dimen/emoji_drawer_left_right_padding"
-                     android:paddingRight="@dimen/emoji_drawer_left_right_padding"
-                     android:layout_width="wrap_content"
-                     android:layout_height="match_parent" />
+        <org.thoughtcrime.securesms.components.RepeatableImageKey
+                android:id="@+id/backspace"
+                android:src="@drawable/ic_emoji_backspace"
+                android:background="@color/emoji_tab_underline"
+                android:paddingLeft="@dimen/emoji_drawer_left_right_padding"
+                android:paddingRight="@dimen/emoji_drawer_left_right_padding"
+                android:layout_width="wrap_content"
+                android:layout_height="match_parent" />
 
     </LinearLayout>
 

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

@@ -9,7 +9,6 @@ import android.support.v4.view.ViewPager;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.util.Pair;
-import android.view.HapticFeedbackConstants;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -20,7 +19,6 @@ import android.widget.BaseAdapter;
 import android.widget.EditText;
 import android.widget.FrameLayout;
 import android.widget.GridView;
-import android.widget.ImageButton;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.RelativeLayout;
@@ -28,19 +26,21 @@ import android.widget.RelativeLayout;
 import com.astuetz.PagerSlidingTabStrip;
 
 import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.components.RepeatableImageKey.KeyEventListener;
 import org.thoughtcrime.securesms.util.Emoji;
 
 public class EmojiDrawer extends KeyboardAwareLinearLayout {
+  private static final KeyEvent DELETE_KEY_EVENT = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL);
 
   private static final int RECENT_TYPE = 0;
   private static final int ALL_TYPE    = 1;
 
+
   private FrameLayout[]        gridLayouts = new FrameLayout[Emoji.PAGES.length+1];
   private EditText             composeText;
   private Emoji                emoji;
   private ViewPager            pager;
   private PagerSlidingTabStrip strip;
-  private ImageButton          backspace;
 
   @SuppressWarnings("unused")
   public EmojiDrawer(Context context) {
@@ -70,7 +70,7 @@ public class EmojiDrawer extends KeyboardAwareLinearLayout {
   }
 
   private void initialize() {
-    LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+    LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     inflater.inflate(R.layout.emoji_drawer, this, true);
 
     initializeResources();
@@ -81,12 +81,18 @@ public class EmojiDrawer extends KeyboardAwareLinearLayout {
   }
 
   private void initializeResources() {
-    this.pager     = (ViewPager                ) findViewById(R.id.emoji_pager);
-    this.strip     = (PagerSlidingTabStrip     ) findViewById(R.id.tabs);
-    this.backspace = (ImageButton              ) findViewById(R.id.backspace);
+    this.pager     = (ViewPager)            findViewById(R.id.emoji_pager);
+    this.strip     = (PagerSlidingTabStrip) findViewById(R.id.tabs);
     this.emoji     = Emoji.getInstance(getContext());
 
-    this.backspace.setOnClickListener(new BackspaceClickListener());
+    RepeatableImageKey backspace = (RepeatableImageKey)findViewById(R.id.backspace);
+    backspace.setOnKeyEventListener(new KeyEventListener() {
+      @Override public void onKeyEvent() {
+        if (composeText != null && composeText.getText().length() > 0) {
+          composeText.dispatchKeyEvent(DELETE_KEY_EVENT);
+        }
+      }
+    });
   }
 
   public void hide() {
@@ -159,19 +165,7 @@ public class EmojiDrawer extends KeyboardAwareLinearLayout {
     }
   }
 
-  private class BackspaceClickListener implements OnClickListener {
-
-    private final KeyEvent deleteKeyEvent = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL);
-
-    @Override
-    public void onClick(View v) {
-      if (composeText.getText().length() > 0) {
-        composeText.dispatchKeyEvent(deleteKeyEvent);
-        v.performHapticFeedback(HapticFeedbackConstants.KEYBOARD_TAP);
-      }
-    }
 
-  }
 
   private class EmojiGridAdapter extends BaseAdapter {
 

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

@@ -0,0 +1,103 @@
+package org.thoughtcrime.securesms.components;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.os.Build.VERSION;
+import android.os.Build.VERSION_CODES;
+import android.util.AttributeSet;
+import android.view.HapticFeedbackConstants;
+import android.view.KeyEvent;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.ViewConfiguration;
+import android.widget.EditText;
+import android.widget.ImageButton;
+
+public class RepeatableImageKey extends ImageButton {
+
+  private KeyEventListener listener;
+
+  public RepeatableImageKey(Context context) {
+    super(context);
+    init();
+  }
+
+  public RepeatableImageKey(Context context, AttributeSet attrs) {
+    super(context, attrs);
+    init();
+  }
+
+  public RepeatableImageKey(Context context, AttributeSet attrs, int defStyleAttr) {
+    super(context, attrs, defStyleAttr);
+    init();
+  }
+
+  @TargetApi(VERSION_CODES.LOLLIPOP)
+  public RepeatableImageKey(Context context, AttributeSet attrs, int defStyleAttr,
+                            int defStyleRes)
+  {
+    super(context, attrs, defStyleAttr, defStyleRes);
+    init();
+  }
+
+  private void init() {
+    setOnClickListener(new RepeaterClickListener());
+    setOnTouchListener(new RepeaterTouchListener());
+  }
+
+  public void setOnKeyEventListener(KeyEventListener listener) {
+    this.listener = listener;
+  }
+
+  private void notifyListener() {
+    if (this.listener != null) this.listener.onKeyEvent();
+  }
+
+  private class RepeaterClickListener implements OnClickListener {
+    @Override public void onClick(View v) {
+      notifyListener();
+    }
+  }
+
+  private class Repeater implements Runnable {
+    @TargetApi(VERSION_CODES.HONEYCOMB_MR1)
+    @Override
+    public void run() {
+      notifyListener();
+      postDelayed(this, VERSION.SDK_INT >= VERSION_CODES.HONEYCOMB_MR1
+                        ? ViewConfiguration.getKeyRepeatDelay()
+                        : 50);
+    }
+  }
+
+  private class RepeaterTouchListener implements OnTouchListener {
+    private Repeater repeater;
+
+    public RepeaterTouchListener() {
+      this.repeater = new Repeater();
+    }
+
+    @TargetApi(VERSION_CODES.HONEYCOMB_MR1)
+    @Override
+    public boolean onTouch(View view, MotionEvent motionEvent) {
+      switch (motionEvent.getAction()) {
+      case MotionEvent.ACTION_DOWN:
+        view.postDelayed(repeater, VERSION.SDK_INT >= VERSION_CODES.HONEYCOMB_MR1
+                                   ? ViewConfiguration.getKeyRepeatTimeout()
+                                   : ViewConfiguration.getLongPressTimeout());
+        performHapticFeedback(HapticFeedbackConstants.KEYBOARD_TAP);
+        return false;
+      case MotionEvent.ACTION_CANCEL:
+      case MotionEvent.ACTION_UP:
+        view.removeCallbacks(repeater);
+        return false;
+      default:
+        return false;
+      }
+    }
+  }
+
+  public interface KeyEventListener {
+    void onKeyEvent();
+  }
+}