Initial checkin of AOSP Messaging app.

b/23110861

Change-Id: I11db999bd10656801e618f78ab2b2ef74136fff1

src/com/android/messaging/ui/ViewPagerTabStrip.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.messaging.ui;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.LinearLayout;
+
+import com.android.messaging.R;
+import com.android.messaging.util.OsUtil;
+
+public class ViewPagerTabStrip extends LinearLayout {
+    private int mSelectedUnderlineThickness;
+    private final Paint mSelectedUnderlinePaint;
+
+    private int mIndexForSelection;
+    private float mSelectionOffset;
+
+    public ViewPagerTabStrip(Context context) {
+        this(context, null);
+    }
+
+    public ViewPagerTabStrip(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        final Resources res = context.getResources();
+
+        mSelectedUnderlineThickness =
+                res.getDimensionPixelSize(R.dimen.pager_tab_underline_selected);
+        int underlineColor = res.getColor(R.color.contact_picker_tab_underline);
+        int backgroundColor = res.getColor(R.color.action_bar_background_color);
+
+        mSelectedUnderlinePaint = new Paint();
+        mSelectedUnderlinePaint.setColor(underlineColor);
+
+        setBackgroundColor(backgroundColor);
+        setWillNotDraw(false);
+    }
+
+    /**
+     * Notifies this view that view pager has been scrolled. We save the tab index
+     * and selection offset for interpolating the position and width of selection
+     * underline.
+     */
+    void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
+        mIndexForSelection = position;
+        mSelectionOffset = positionOffset;
+        invalidate();
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        int childCount = getChildCount();
+
+        // Thick colored underline below the current selection
+        if (childCount > 0) {
+            View selectedTitle = getChildAt(mIndexForSelection);
+            int selectedLeft = selectedTitle.getLeft();
+            int selectedRight = selectedTitle.getRight();
+            final boolean isRtl = isRtl();
+            final boolean hasNextTab = isRtl ? mIndexForSelection > 0
+                    : (mIndexForSelection < (getChildCount() - 1));
+            if ((mSelectionOffset > 0.0f) && hasNextTab) {
+                // Draw the selection partway between the tabs
+                View nextTitle = getChildAt(mIndexForSelection + (isRtl ? -1 : 1));
+                int nextLeft = nextTitle.getLeft();
+                int nextRight = nextTitle.getRight();
+
+                selectedLeft = (int) (mSelectionOffset * nextLeft +
+                        (1.0f - mSelectionOffset) * selectedLeft);
+                selectedRight = (int) (mSelectionOffset * nextRight +
+                        (1.0f - mSelectionOffset) * selectedRight);
+            }
+
+            int height = getHeight();
+            canvas.drawRect(selectedLeft, height - mSelectedUnderlineThickness,
+                    selectedRight, height, mSelectedUnderlinePaint);
+        }
+    }
+
+    private boolean isRtl() {
+        return OsUtil.isAtLeastJB_MR2() ? getLayoutDirection() == View.LAYOUT_DIRECTION_RTL : false;
+    }
+}