src/com/android/launcher3/BaseContainerView.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.launcher3;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.PointF;
import android.graphics.Rect;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.InsetDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.FrameLayout;

import com.android.launcher3.allapps.AllAppsContainerView;
import com.android.launcher3.config.FeatureFlags;
import com.android.launcher3.util.TransformingTouchDelegate;

/**
 * A base container view, which supports resizing.
 */
public abstract class BaseContainerView extends FrameLayout
        implements DeviceProfile.LauncherLayoutChangeListener {

    private static final Rect sBgPaddingRect = new Rect();

    protected final Drawable mBaseDrawable;

    private View mRevealView;
    private View mContent;

    private TransformingTouchDelegate mTouchDelegate;

    private final PointF mLastTouchDownPosPx = new PointF(-1.0f, -1.0f);

    public BaseContainerView(Context context) {
        this(context, null);
    }

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

    public BaseContainerView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        if (this instanceof AllAppsContainerView) {
            mBaseDrawable = new ColorDrawable();
        } else {
            TypedArray a = context.obtainStyledAttributes(attrs,
                    R.styleable.BaseContainerView, defStyleAttr, 0);
            mBaseDrawable = a.getDrawable(R.styleable.BaseContainerView_revealBackground);
            a.recycle();
        }
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        DeviceProfile grid = Launcher.getLauncher(getContext()).getDeviceProfile();
        grid.addLauncherLayoutChangedListener(this);

        View touchDelegateTargetView = getTouchDelegateTargetView();
        if (touchDelegateTargetView != null) {
            mTouchDelegate = new TransformingTouchDelegate(touchDelegateTargetView);
            ((View) touchDelegateTargetView.getParent()).setTouchDelegate(mTouchDelegate);
        }
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();

        DeviceProfile grid = Launcher.getLauncher(getContext()).getDeviceProfile();
        grid.removeLauncherLayoutChangedListener(this);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();

        mContent = findViewById(R.id.main_content);
        mRevealView = findViewById(R.id.reveal_view);

        updatePaddings();
    }

    @Override
    public void onLauncherLayoutChanged() {
        updatePaddings();
    }

    /**
     * Calculate the background padding as it can change due to insets/content padding change.
     */
    private void updatePaddings() {
        DeviceProfile grid = Launcher.getLauncher(getContext()).getDeviceProfile();
        int[] padding = grid.getContainerPadding();

        int paddingLeft = padding[0];
        int paddingRight = padding[1];
        int paddingTop = 0;
        int paddingBottom = 0;

        if (!grid.isVerticalBarLayout()) {
            paddingLeft += grid.edgeMarginPx;
            paddingRight += grid.edgeMarginPx;
            paddingTop = paddingBottom = grid.edgeMarginPx;
        }
        updateBackground(paddingLeft, paddingTop, paddingRight, paddingBottom);
    }

    /**
     * Update the background for the reveal view and content view based on the background padding.
     */
    protected void updateBackground(int paddingLeft, int paddingTop,
            int paddingRight, int paddingBottom) {
        mRevealView.setBackground(new InsetDrawable(mBaseDrawable,
                paddingLeft, paddingTop, paddingRight, paddingBottom));
        mContent.setBackground(new InsetDrawable(mBaseDrawable,
                paddingLeft, paddingTop, paddingRight, paddingBottom));
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);

        View touchDelegateTargetView = getTouchDelegateTargetView();
        if (touchDelegateTargetView != null) {
            getRevealView().getBackground().getPadding(sBgPaddingRect);
            mTouchDelegate.setBounds(
                    touchDelegateTargetView.getLeft() - sBgPaddingRect.left,
                    touchDelegateTargetView.getTop() - sBgPaddingRect.top,
                    touchDelegateTargetView.getRight() + sBgPaddingRect.right,
                    touchDelegateTargetView.getBottom() + sBgPaddingRect.bottom);
        }
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return handleTouchEvent(ev);
    }

    @SuppressLint("ClickableViewAccessibility")
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return handleTouchEvent(ev);
    }

    public void setRevealDrawableColor(int color) {
        ((ColorDrawable) mBaseDrawable).setColor(color);
    }

    public final View getContentView() {
        return mContent;
    }

    public final View getRevealView() {
        return mRevealView;
    }


    /**
     * Handles the touch events that shows the workspace when clicking outside the bounds of the
     * touch delegate target view.
     */
    private boolean handleTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // Check if the touch is outside touch delegate target view
                View touchDelegateTargetView = getTouchDelegateTargetView();
                float leftBoundPx = touchDelegateTargetView.getLeft();
                if (ev.getX() < leftBoundPx ||
                        ev.getX() > (touchDelegateTargetView.getWidth() + leftBoundPx)) {
                    mLastTouchDownPosPx.set((int) ev.getX(), (int) ev.getY());
                }
                break;
            case MotionEvent.ACTION_UP:
                if (mLastTouchDownPosPx.x > -1) {
                    ViewConfiguration viewConfig = ViewConfiguration.get(getContext());
                    float dx = ev.getX() - mLastTouchDownPosPx.x;
                    float dy = ev.getY() - mLastTouchDownPosPx.y;
                    float distance = PointF.length(dx, dy);
                    if (distance < viewConfig.getScaledTouchSlop()) {
                        // The background was clicked, so just go home
                        Launcher.getLauncher(getContext()).showWorkspace(true);
                        return true;
                    }
                }
                // Fall through
            case MotionEvent.ACTION_CANCEL:
                mLastTouchDownPosPx.set(-1, -1);
                break;
        }
        return false;
    }

    public abstract View getTouchDelegateTargetView();
}