de.vanita5.twittnuker.util.SwipebackActivityUtils.java Source code

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Here is the source code for de.vanita5.twittnuker.util.SwipebackActivityUtils.java

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/*
 * Twittnuker - Twitter client for Android
 *
 * Copyright (C) 2013-2014 vanita5 <mail@vanita5.de>
 *
 * This program incorporates a modified version of Twidere.
 * Copyright (C) 2012-2014 Mariotaku Lee <mariotaku.lee@gmail.com>
 *
 * 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 de.vanita5.twittnuker.util;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.view.View;
import android.view.Window;

import de.vanita5.twittnuker.TwittnukerConstants;
import de.vanita5.twittnuker.app.TwittnukerApplication;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class SwipebackActivityUtils implements TwittnukerConstants {

    public static void setActivityScreenshot(final Activity activity, final Intent target) {
        if (activity == null || target == null)
            return;
        final SharedPreferences prefs = activity.getSharedPreferences(SHARED_PREFERENCES_NAME,
                Context.MODE_PRIVATE);
        if (!prefs.getBoolean(KEY_SWIPE_BACK, true))
            return;
        final TwittnukerApplication app = TwittnukerApplication.getInstance(activity);
        final SwipebackScreenshotManager sm = app.getSwipebackScreenshotManager();
        final long key = System.currentTimeMillis();
        final Bitmap sc = getActivityScreenshot(activity, View.DRAWING_CACHE_QUALITY_LOW);
        sm.put(key, sc, ThemeUtils.isTransparentBackground(activity));
        target.putExtra(EXTRA_ACTIVITY_SCREENSHOT_ID, key);
    }

    public static void startSwipebackActivity(final Activity activity, final Intent intent) {
        setActivityScreenshot(activity, intent);
        activity.startActivityForResult(intent, REQUEST_SWIPEBACK_ACTIVITY);
    }

    public static void startSwipebackActivity(final Activity activity, final Intent intent, final Bundle options) {
        setActivityScreenshot(activity, intent);
        ActivityCompat.startActivityForResult(activity, intent, REQUEST_SWIPEBACK_ACTIVITY, options);
    }

    /**
     * 
     * May cause OutOfMemoryError
     * 
     * @param activity
     * @param cacheQuality
     * @return Activity screenshot
     */
    private static Bitmap getActivityScreenshot(final Activity activity, final int cacheQuality) {
        try {
            return getActivityScreenshotInternal(activity, cacheQuality);
        } catch (final OutOfMemoryError oom) {
            return null;
        } catch (final StackOverflowError sof) {
            return null;
        }
    }

    /**
     * 
     * May cause OutOfMemoryError
     * 
     * @param activity
     * @param cacheQuality
     * @return Activity screenshot
     */
    private static Bitmap getActivityScreenshotInternal(final Activity activity, final int cacheQuality) {
        if (activity == null)
            return null;
        final Window w = activity.getWindow();
        final View view = w.getDecorView();
        final int width = view.getWidth(), height = view.getHeight();
        if (width <= 0 || height <= 0)
            return null;
        final Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_4444);
        final Rect frame = new Rect();
        view.getWindowVisibleDisplayFrame(frame);
        // Remove window background behind status bar.
        final Canvas c = new Canvas(b);
        view.draw(c);
        final Paint paint = new Paint();
        paint.setColor(Color.TRANSPARENT);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        c.drawRect(frame.left, 0, frame.right, frame.top, paint);
        return b;
    }

    public static class SwipebackScreenshotManager {

        private static final String DIR_NAME_SWIPEBACK_CACHE = "swipeback_cache";
        private static final CompressFormat COMPRESS_FORMAT = Bitmap.CompressFormat.JPEG;
        private static final CompressFormat COMPRESS_FORMAT_TRANSPARENT = Bitmap.CompressFormat.PNG;
        private final File mCacheDir;

        public SwipebackScreenshotManager(final Context context) {
            mCacheDir = Utils.getBestCacheDir(context, DIR_NAME_SWIPEBACK_CACHE);
        }

        public Bitmap get(final long id) {
            final File f = new File(mCacheDir, String.valueOf(id));
            if (!f.exists())
                return null;
            try {
                return BitmapFactory.decodeFile(f.getAbsolutePath());
            } catch (final OutOfMemoryError e) {
                return null;
            } finally {
                System.gc();
            }
        }

        public void put(final long id, final Bitmap bitmap, final boolean alphaChannel) {
            if (bitmap == null || bitmap.isRecycled())
                return;
            try {
                final OutputStream os = new FileOutputStream(new File(mCacheDir, String.valueOf(id)));
                bitmap.compress(alphaChannel ? COMPRESS_FORMAT_TRANSPARENT : COMPRESS_FORMAT, 75, os);
                bitmap.recycle();
            } catch (final IOException e) {
                e.printStackTrace();
            } finally {
                System.gc();
            }
        }

        public boolean remove(final long id) {
            final File f = new File(mCacheDir, String.valueOf(id));
            if (!f.exists())
                return false;
            try {
                return f.delete();
            } finally {
                System.gc();
            }
        }

    }
}