ui/views/Elevation/ElevationDrag/Application/src/main/java/com/example/android/elevationdrag/ElevationDragFragment.java

/*
 * Copyright (C) 2014 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.example.android.elevationdrag;

import com.example.android.common.logger.Log;

import android.graphics.Outline;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewOutlineProvider;

public class ElevationDragFragment extends Fragment {

    public static final String TAG = "ElevationDragFragment";

    /* The circular outline provider */
    private ViewOutlineProvider mOutlineProviderCircle;

    /* The current elevation of the floating view. */
    private float mElevation = 0;

    /* The step in elevation when changing the Z value */
    private int mElevationStep;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mOutlineProviderCircle = new CircleOutlineProvider();

        mElevationStep = getResources().getDimensionPixelSize(R.dimen.elevation_step);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.ztranslation, container, false);

        /* Find the {@link View} to apply z-translation to. */
        final View floatingShape = rootView.findViewById(R.id.circle);

        /* Define the shape of the {@link View}'s shadow by setting one of the {@link Outline}s. */
        floatingShape.setOutlineProvider(mOutlineProviderCircle);

        /* Clip the {@link View} with its outline. */
        floatingShape.setClipToOutline(true);

        DragFrameLayout dragLayout = ((DragFrameLayout) rootView.findViewById(R.id.main_layout));

        dragLayout.setDragFrameController(new DragFrameLayout.DragFrameLayoutController() {

            @Override
            public void onDragDrop(boolean captured) {
                /* Animate the translation of the {@link View}. Note that the translation
                 is being modified, not the elevation. */
                floatingShape.animate()
                        .translationZ(captured ? 50 : 0)
                        .setDuration(100);
                Log.d(TAG, captured ? "Drag" : "Drop");
            }
        });

        dragLayout.addDragView(floatingShape);

        /* Raise the circle in z when the "z+" button is clicked. */
        rootView.findViewById(R.id.raise_bt).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mElevation += mElevationStep;
                Log.d(TAG, String.format("Elevation: %.1f", mElevation));
                floatingShape.setElevation(mElevation);
            }
        });

        /* Lower the circle in z when the "z-" button is clicked. */
        rootView.findViewById(R.id.lower_bt).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mElevation -= mElevationStep;
                // Don't allow for negative values of Z.
                if (mElevation < 0) {
                    mElevation = 0;
                }
                Log.d(TAG, String.format("Elevation: %.1f", mElevation));
                floatingShape.setElevation(mElevation);
            }
        });

        return rootView;
    }

    /**
     * ViewOutlineProvider which sets the outline to be an oval which fits the view bounds.
     */
    private class CircleOutlineProvider extends ViewOutlineProvider {
        @Override
        public void getOutline(View view, Outline outline) {
            outline.setOval(0, 0, view.getWidth(), view.getHeight());
        }
    }

}