open-keychain/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/widget/FoldableLinearLayout.java

/*
 * Copyright (C) 2017 Schürmann & Breitmoser GbR
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.sufficientlysecure.keychain.ui.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import org.sufficientlysecure.keychain.R;

/**
 * Class representing a LinearLayout that can fold and hide it's content when pressed
 * To use just add the following to your xml layout
 * <p/>
 * <org.sufficientlysecure.keychain.ui.widget.FoldableLinearLayout
 * android:layout_width="wrap_content"
 * android:layout_height="wrap_content"
 * custom:foldedLabel="@string/TEXT_TO_DISPLAY_WHEN_FOLDED"
 * custom:unFoldedLabel="@string/TEXT_TO_DISPLAY_WHEN_UNFOLDED">
 * <p/>
 * <include layout="@layout/ELEMENTS_TO_BE_FOLDED"/>
 * <p/>
 * </org.sufficientlysecure.keychain.ui.widget.FoldableLinearLayout>
 */
public class FoldableLinearLayout extends LinearLayout {

    private ImageView mFoldableIcon;
    private boolean mFolded;
    private boolean mHasMigrated = false;
    private Integer mShortAnimationDuration = null;
    private TextView mFoldableTextView = null;
    private LinearLayout mFoldableContainer = null;
    private View mFoldableLayout = null;

    private String mFoldedLabel;
    private String mUnFoldedLabel;
    private boolean mInitializeFolded;

    public FoldableLinearLayout(Context context) {
        super(context);
        processAttributes(context, null);
    }

    public FoldableLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        processAttributes(context, attrs);
    }

    public FoldableLinearLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs);
        processAttributes(context, attrs);
    }

    /**
     * Load given attributes to inner variables,
     *
     * @param context
     * @param attrs
     */
    private void processAttributes(Context context, AttributeSet attrs) {
        if (attrs != null) {
            TypedArray a = context.obtainStyledAttributes(attrs,
                    R.styleable.FoldableLinearLayout, 0, 0);
            mFoldedLabel = a.getString(R.styleable.FoldableLinearLayout_foldedLabel);
            mUnFoldedLabel = a.getString(R.styleable.FoldableLinearLayout_unFoldedLabel);
            mInitializeFolded = a.getBoolean(R.styleable.FoldableLinearLayout_initializeFolded, true);
            a.recycle();
        }
        // If any attribute isn't found then set a default one
        mFoldedLabel = (mFoldedLabel == null) ? context.getString(R.string.none) : mFoldedLabel;
        mUnFoldedLabel = (mUnFoldedLabel == null) ? context.getString(R.string.none) : mUnFoldedLabel;
    }

    @Override
    protected void onFinishInflate() {
        // if the migration has already happened
        // there is no need to move any children
        if (!mHasMigrated) {
            migrateChildrenToContainer();
            mHasMigrated = true;
        }

        initialiseInnerViews();

        if (!mInitializeFolded) {
            toggleFolded();
        }

        super.onFinishInflate();
    }

    /**
     * Migrates Child views as declared in xml to the inner foldableContainer
     */
    private void migrateChildrenToContainer() {
        // Collect children of FoldableLinearLayout as declared in XML
        int childNum = getChildCount();
        View[] children = new View[childNum];

        for (int i = 0; i < childNum; i++) {
            children[i] = getChildAt(i);
        }
        if (children[0].getId() == R.id.foldableControl) {

        }

        // remove all of them from FoldableLinearLayout
        detachAllViewsFromParent();

        // Inflate the inner foldable_linearlayout.xml
        LayoutInflater inflator = (LayoutInflater) getContext().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);

        mFoldableLayout = inflator.inflate(R.layout.foldable_linearlayout, this, true);
        mFoldableContainer = mFoldableLayout.findViewById(R.id.foldableContainer);

        // Push previously collected children into foldableContainer.
        for (int i = 0; i < childNum; i++) {
            addView(children[i]);
        }
    }

    private void initialiseInnerViews() {
        mFoldableIcon = mFoldableLayout.findViewById(R.id.foldableIcon);
        mFoldableIcon.setImageResource(R.drawable.ic_expand_more_black_24dp);
        mFoldableTextView = mFoldableLayout.findViewById(R.id.foldableText);
        mFoldableTextView.setText(mFoldedLabel);

        // retrieve and cache the system's short animation time
        mShortAnimationDuration = getResources().getInteger(android.R.integer.config_shortAnimTime);

        LinearLayout foldableControl = mFoldableLayout.findViewById(R.id.foldableControl);
        foldableControl.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                toggleFolded();
            }
        });

    }

    private void toggleFolded() {
        mFolded = !mFolded;
        if (mFolded) {
            mFoldableIcon.setImageResource(R.drawable.ic_expand_less_black_24dp);
            mFoldableContainer.setVisibility(View.VISIBLE);
            AlphaAnimation animation = new AlphaAnimation(0f, 1f);
            animation.setDuration(mShortAnimationDuration);
            mFoldableContainer.startAnimation(animation);
            mFoldableTextView.setText(mUnFoldedLabel);

        } else {
            mFoldableIcon.setImageResource(R.drawable.ic_expand_more_black_24dp);
            AlphaAnimation animation = new AlphaAnimation(1f, 0f);
            animation.setDuration(mShortAnimationDuration);
            animation.setAnimationListener(new Animation.AnimationListener() {
                @Override
                public void onAnimationStart(Animation animation) {
                }

                @Override
                public void onAnimationEnd(Animation animation) {
                    // making sure that at the end the container is completely removed from view
                    mFoldableContainer.setVisibility(View.GONE);
                }

                @Override
                public void onAnimationRepeat(Animation animation) {
                }
            });
            mFoldableContainer.startAnimation(animation);
            mFoldableTextView.setText(mFoldedLabel);
        }
    }

    /**
     * Adds provided child view to foldableContainer View
     *
     * @param child
     */
    @Override
    public void addView(View child) {
        if (mFoldableContainer != null) {
            mFoldableContainer.addView(child);
        }
    }
}