open-keychain/OpenPGP-Keychain/src/org/sufficientlysecure/keychain/compatibility/DialogFragmentWorkaround.java

/*
 * Copyright (C) 2012 Dominik Schürmann <dominik@dominikschuermann.de>
 *
 * 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 org.sufficientlysecure.keychain.compatibility;

import android.os.Build;
import android.os.Handler;

/**
 * Bug on Android >= 4.2
 * 
 * http://code.google.com/p/android/issues/detail?id=41901
 * 
 * DialogFragment disappears on pressing home and comming back. This also happens especially in
 * FileDialogFragment after launching a file manager and coming back.
 * 
 * Usage: <code>
 * DialogFragmentWorkaround.INTERFACE.runnableRunDelayed(new Runnable() {
 *          public void run() {
 *              // show dialog...
 *          }
 *      });
 * </code>
 */
public class DialogFragmentWorkaround {
    public static final SDKLevel17Interface INTERFACE = ((Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) ? new SDKLevel17Impl()
            : new SDKLevelPriorLevel17Impl());

    private static final int RUNNABLE_DELAY = 300;

    public interface SDKLevel17Interface {
        // Workaround for http://code.google.com/p/android/issues/detail?id=41901
        void runnableRunDelayed(Runnable runnable);
    }

    private static class SDKLevelPriorLevel17Impl implements SDKLevel17Interface {
        @Override
        public void runnableRunDelayed(Runnable runnable) {
            runnable.run();
        }
    }

    private static class SDKLevel17Impl implements SDKLevel17Interface {
        @Override
        public void runnableRunDelayed(Runnable runnable) {
            new Handler().postDelayed(runnable, RUNNABLE_DELAY);
        }
    }

    // Can't instantiate this class
    private DialogFragmentWorkaround() {
    }
}