diff options
Diffstat (limited to 'java/com/android/dialer/contactsfragment/FastScroller.java')
-rw-r--r-- | java/com/android/dialer/contactsfragment/FastScroller.java | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/java/com/android/dialer/contactsfragment/FastScroller.java b/java/com/android/dialer/contactsfragment/FastScroller.java new file mode 100644 index 000000000..980032cb5 --- /dev/null +++ b/java/com/android/dialer/contactsfragment/FastScroller.java @@ -0,0 +1,129 @@ +/* + * Copyright (C) 2017 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.dialer.contactsfragment; + +import android.content.Context; +import android.support.annotation.NonNull; +import android.support.v7.widget.LinearLayoutManager; +import android.support.v7.widget.RecyclerView; +import android.util.AttributeSet; +import android.view.MotionEvent; +import android.view.View; +import android.widget.RelativeLayout; +import android.widget.TextView; + +/** Widget to add fast scrolling to {@link ContactsFragment}. */ +public class FastScroller extends RelativeLayout { + + private final int touchTargetWidth; + + private ContactsAdapter adapter; + private LinearLayoutManager layoutManager; + + private TextView container; + private View scrollBar; + + private boolean dragStarted; + + public FastScroller(Context context, AttributeSet attrs) { + super(context, attrs); + touchTargetWidth = + context.getResources().getDimensionPixelSize(R.dimen.fast_scroller_touch_target_width); + } + + @Override + protected void onFinishInflate() { + super.onFinishInflate(); + container = (TextView) findViewById(R.id.fast_scroller_container); + scrollBar = findViewById(R.id.fast_scroller_scroll_bar); + } + + void setup(ContactsAdapter adapter, LinearLayoutManager layoutManager) { + this.adapter = adapter; + this.layoutManager = layoutManager; + } + + @Override + public boolean onTouchEvent(@NonNull MotionEvent event) { + // Don't override if touch event isn't within desired touch target and dragging hasn't started. + if (!dragStarted && getWidth() - touchTargetWidth - event.getX() > 0) { + return super.onTouchEvent(event); + } + + switch (event.getAction()) { + case MotionEvent.ACTION_DOWN: + dragStarted = true; + container.setVisibility(VISIBLE); + scrollBar.setSelected(true); + // fall through + case MotionEvent.ACTION_MOVE: + setContainerAndScrollBarPosition(event.getY()); + setRecyclerViewPosition(event.getY()); + return true; + case MotionEvent.ACTION_UP: + case MotionEvent.ACTION_CANCEL: + dragStarted = false; + container.setVisibility(INVISIBLE); + scrollBar.setSelected(false); + return true; + } + return super.onTouchEvent(event); + } + + private void setRecyclerViewPosition(float y) { + final int itemCount = adapter.getItemCount(); + float scrolledPosition = getScrolledPercentage(y) * (float) itemCount; + int targetPos = getValueInRange(0, itemCount - 1, (int) scrolledPosition); + layoutManager.scrollToPositionWithOffset(targetPos, 0); + container.setText(adapter.getHeaderString(targetPos)); + } + + // Returns a float in range [0, 1] which represents the position of the scroller. + private float getScrolledPercentage(float y) { + if (scrollBar.getY() == 0) { + return 0f; + } else if (scrollBar.getY() + scrollBar.getHeight() >= getHeight()) { + return 1f; + } else { + return y / (float) getHeight(); + } + } + + private int getValueInRange(int min, int max, int value) { + int minimum = Math.max(min, value); + return Math.min(minimum, max); + } + + void updateContainerAndScrollBarPosition(RecyclerView recyclerView) { + if (!scrollBar.isSelected()) { + int verticalScrollOffset = recyclerView.computeVerticalScrollOffset(); + int verticalScrollRange = recyclerView.computeVerticalScrollRange(); + float proportion = (float) verticalScrollOffset / ((float) verticalScrollRange - getHeight()); + setContainerAndScrollBarPosition(getHeight() * proportion); + } + } + + private void setContainerAndScrollBarPosition(float y) { + int scrollBarHeight = scrollBar.getHeight(); + int containerHeight = container.getHeight(); + scrollBar.setY( + getValueInRange(0, getHeight() - scrollBarHeight, (int) (y - scrollBarHeight / 2))); + container.setY( + getValueInRange( + 0, getHeight() - containerHeight - scrollBarHeight / 2, (int) (y - containerHeight))); + } +} |