AlphaJumpOverlayView.java
/*
* Copyright 2018 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 androidx.car.widget;
import android.content.Context;
import android.content.res.Resources;
import android.util.TypedValue;
import android.view.LayoutInflater;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.car.R;
import androidx.gridlayout.widget.GridLayout;
import java.util.List;
/**
* This view shows a grid of alphabetic letters that you can tap on to advance a list to the
* beginning of that list.
*/
public class AlphaJumpOverlayView extends GridLayout {
private AlphaJumpAdapter mAdapter;
private PagedListView mPagedListView;
private List<AlphaJumpBucket> mBuckets;
private LayoutInflater mInflater;
private Animation mOpenAnimation;
private Animation mCloseAnimation;
public AlphaJumpOverlayView(@NonNull Context context) {
super(context);
Resources res = context.getResources();
setOrientation(HORIZONTAL);
// Get the background color from the theme and set it.
TypedValue typedValue = new TypedValue();
boolean hasAttribute = context.getTheme().resolveAttribute(
R.attr.alphaJumpPickerBackground, typedValue, true);
setBackgroundColor(hasAttribute
? typedValue.data
: context.getColor(R.color.car_card_dark));
setColumnCount(res.getInteger(R.integer.car_alpha_jump_button_columns));
//Subtract the buttons' margin from the side margin.
int carMargin = res.getDimensionPixelSize(R.dimen.car_margin);
int buttonMargin = res.getDimensionPixelSize(R.dimen.car_padding_0);
int padding = carMargin - buttonMargin;
setPadding(padding, 0, padding, 0);
}
void init(PagedListView plv, AlphaJumpAdapter adapter) {
Context context = getContext();
mInflater = LayoutInflater.from(context);
mPagedListView = plv;
mAdapter = adapter;
mBuckets = adapter.getAlphaJumpBuckets();
mOpenAnimation = AnimationUtils
.loadAnimation(context, R.anim.car_alpha_picker_enter);
mCloseAnimation = AnimationUtils
.loadAnimation(context, R.anim.car_alpha_picker_exit);
createButtons();
}
private void createButtons() {
removeAllViews();
for (AlphaJumpBucket bucket : mBuckets) {
View container = mInflater
.inflate(R.layout.car_alpha_jump_picker_button, this, false);
TextView btn = container.findViewById(R.id.button);
btn.setText(bucket.getLabel());
btn.setOnClickListener(this::onButtonClick);
btn.setTag(bucket);
if (bucket.isEmpty()) {
btn.setEnabled(false);
btn.setBackgroundResource(R.color.alpha_picker_unavailable_bg);
}
addView(container);
}
}
private void onButtonClick(View v) {
hide();
AlphaJumpBucket bucket = (AlphaJumpBucket) v.getTag();
if (bucket != null) {
mAdapter.onAlphaJumpLeave(bucket);
mPagedListView.snapToPosition(bucket.getIndex());
}
}
/**
* Show the Alpha Jump Overview by toggling its visibility
*/
public void show() {
mAdapter.onAlphaJumpEnter();
setVisibility(VISIBLE);
startAnimation(mOpenAnimation);
}
/**
* Hide the Alpha Jump Overview by toggling its visibility
*/
public void hide() {
startAnimation(mCloseAnimation);
setVisibility(GONE);
}
}