packages/SystemUI/src/com/android/systemui/recents/history/RecentsHistoryView.java

/*
 * 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.systemui.recents.history;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Rect;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.util.AttributeSet;
import android.view.View;
import android.view.WindowInsets;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
import android.widget.LinearLayout;
import com.android.systemui.R;
import com.android.systemui.recents.Recents;
import com.android.systemui.recents.RecentsActivity;
import com.android.systemui.recents.RecentsConfiguration;
import com.android.systemui.recents.events.EventBus;
import com.android.systemui.recents.events.activity.PackagesChangedEvent;
import com.android.systemui.recents.misc.ReferenceCountedTrigger;
import com.android.systemui.recents.misc.SystemServicesProxy;
import com.android.systemui.recents.model.TaskStack;

/**
 * A list of the recent tasks that are not in the stack.
 */
public class RecentsHistoryView extends LinearLayout {

    private static final String TAG = "RecentsHistoryView";
    private static final boolean DEBUG = false;

    private RecyclerView mRecyclerView;
    private RecentsHistoryAdapter mAdapter;
    private RecentsHistoryItemTouchCallbacks mItemTouchHandler;
    private boolean mIsVisible;
    private Rect mSystemInsets = new Rect();

    private Interpolator mFastOutSlowInInterpolator;
    private Interpolator mFastOutLinearInInterpolator;
    private int mHistoryTransitionDuration;

    public RecentsHistoryView(Context context) {
        super(context);
    }

    public RecentsHistoryView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RecentsHistoryView(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public RecentsHistoryView(Context context, AttributeSet attrs, int defStyleAttr,
            int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        Resources res = context.getResources();
        mAdapter = new RecentsHistoryAdapter(context);
        mItemTouchHandler = new RecentsHistoryItemTouchCallbacks(context, mAdapter);
        mHistoryTransitionDuration = res.getInteger(R.integer.recents_history_transition_duration);
        mFastOutSlowInInterpolator = AnimationUtils.loadInterpolator(context,
                com.android.internal.R.interpolator.fast_out_slow_in);
        mFastOutLinearInInterpolator = AnimationUtils.loadInterpolator(context,
                com.android.internal.R.interpolator.fast_out_linear_in);
    }

    /**
     * Updates this history view with the recent tasks, and then shows it.
     */
    public void show(TaskStack stack, ReferenceCountedTrigger postHideAnimationTrigger) {
        setVisibility(View.VISIBLE);
        setAlpha(0f);
        postHideAnimationTrigger.addLastDecrementRunnable(new Runnable() {
            @Override
            public void run() {
                animate()
                        .alpha(1f)
                        .setDuration(mHistoryTransitionDuration)
                        .setInterpolator(mFastOutSlowInInterpolator)
                        .withLayer()
                        .start();
            }
        });
        mAdapter.updateTasks(getContext(), stack);
        mIsVisible = true;
    }

    /**
     * Hides this history view.
     */
    public void hide(boolean animate, final ReferenceCountedTrigger postAnimationTrigger) {
        if (animate) {
            animate()
                    .alpha(0f)
                    .setDuration(mHistoryTransitionDuration)
                    .setInterpolator(mFastOutLinearInInterpolator)
                    .withEndAction(new Runnable() {
                        @Override
                        public void run() {
                            setVisibility(View.INVISIBLE);
                            if (postAnimationTrigger != null) {
                                postAnimationTrigger.decrement();
                            }
                        }
                    })
                    .withLayer()
                    .start();
            if (postAnimationTrigger != null) {
                postAnimationTrigger.increment();
            }
        } else {
            setAlpha(0f);
            setVisibility(View.INVISIBLE);
        }
        mIsVisible = false;
    }

    /**
     * Updates the system insets of this history view to the provided values.
     */
    public void setSystemInsets(Rect systemInsets) {
        mSystemInsets.set(systemInsets.left, systemInsets.top, systemInsets.right, systemInsets.bottom);
        requestLayout();
    }

    /**
     * Returns whether this view is visible.
     */
    public boolean isVisible() {
        return mIsVisible;
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        mRecyclerView = (RecyclerView) findViewById(R.id.list);
        mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
        ItemTouchHelper touchHelper = new ItemTouchHelper(mItemTouchHandler);
        touchHelper.attachToRecyclerView(mRecyclerView);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        RecentsConfiguration config = Recents.getConfiguration();
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);

        // Pad the view to align the history with the stack layout
        Rect taskStackBounds = new Rect();
        config.getTaskStackBounds(new Rect(0, 0, width, height), mSystemInsets.top,
                mSystemInsets.right, new Rect() /* searchBarSpaceBounds */, taskStackBounds);
        int stackWidthPadding = (int) (config.taskStackWidthPaddingPct * taskStackBounds.width());
        int stackHeightPadding = mContext.getResources().getDimensionPixelSize(
                R.dimen.recents_stack_top_padding);
        mRecyclerView.setPadding(stackWidthPadding + mSystemInsets.left,
                stackHeightPadding + mSystemInsets.top,
                stackWidthPadding + mSystemInsets.right, mSystemInsets.bottom);

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    protected void onAttachedToWindow() {
        EventBus.getDefault().register(this, RecentsActivity.EVENT_BUS_PRIORITY + 1);
        super.onAttachedToWindow();
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        EventBus.getDefault().unregister(this);
    }

    @Override
    public WindowInsets onApplyWindowInsets(WindowInsets insets) {
        setSystemInsets(insets.getSystemWindowInsets());
        return insets;
    }

    /**** EventBus Events ****/

    public final void onBusEvent(PackagesChangedEvent event) {
        mAdapter.removeTasks(event.packageName, event.userId);
    }
}