Android Open Source - qrcode-android Inactivity Timer

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License

The source code is released under:
MIT License
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Java Source Code

/*
 * Copyright (C) 2010 ZXing authors//from  w  w  w  .  ja  v a 2s  . c o m
 *
 * 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.google.zxing.client.android;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.AsyncTask;
import android.os.BatteryManager;
import android.util.Log;
import com.google.zxing.client.android.common.executor.AsyncTaskExecInterface;
import com.google.zxing.client.android.common.executor.AsyncTaskExecManager;

/**
 * Finishes an activity after a period of inactivity if the device is on battery power.
 */
final class InactivityTimer
{

    private static final String TAG = InactivityTimer.class.getSimpleName();

    private static final long INACTIVITY_DELAY_MS = 5 * 60 * 1000L;

    private final Activity activity;
    private final AsyncTaskExecInterface taskExec;
    private final BroadcastReceiver powerStatusReceiver;
    private InactivityAsyncTask inactivityTask;

    InactivityTimer(Activity activity)
    {
        this.activity = activity;
        taskExec = new AsyncTaskExecManager().build();
        powerStatusReceiver = new PowerStatusReceiver();
        onActivity();
    }

    synchronized void onActivity()
    {
        cancel();
        inactivityTask = new InactivityAsyncTask();
        taskExec.execute(inactivityTask);
    }

    public void onPause()
    {
        cancel();
        activity.unregisterReceiver(powerStatusReceiver);
    }

    public void onResume()
    {
        activity.registerReceiver(powerStatusReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
        onActivity();
    }

    private synchronized void cancel()
    {
        AsyncTask<?, ?, ?> task = inactivityTask;
        if (task != null)
        {
            task.cancel(true);
            inactivityTask = null;
        }
    }

    void shutdown()
    {
        cancel();
    }

    private final class PowerStatusReceiver extends BroadcastReceiver
    {

        @Override
        public void onReceive(Context context, Intent intent)
        {
            if (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction()))
            {
                // 0 indicates that we're on battery
                boolean onBatteryNow = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1) <= 0;
                if (onBatteryNow)
                {
                    InactivityTimer.this.onActivity();
                } else
                {
                    InactivityTimer.this.cancel();
                }
            }
        }
    }

    private final class InactivityAsyncTask extends AsyncTask<Object, Object, Object>
    {

        @Override
        protected Object doInBackground(Object... objects)
        {
            try
            {
                Thread.sleep(INACTIVITY_DELAY_MS);
                Log.i(TAG, "Finishing activity due to inactivity");
                activity.finish();
            } catch (InterruptedException e)
            {
                // continue without killing
            }
            return null;
        }
    }

}
Java Source Code List
