Android Open Source - Rejsekort-Reminder Main Activity

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License

The source code is released under:

GNU General Public License

Java Source Code

package com.example.publictransportation;
//from  w  w  w . ja v a  2s.  co  m
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningServiceInfo;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Switch;
import android.widget.Toast;

//import com.example.publictransportation.service.TrackerService;

public class MainActivity extends Activity {

  // UI
  Switch onOffSwitch;

  // used to toggle switch off when there's no wifi
  private WifiStateReceiver wifiStateReceiver;

  // system services
  private WifiManager wifiManager;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // On/Off switch to turn on and off the whole service
    onOffSwitch = (Switch) findViewById(R.id.on_off_switch);

    wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);

    Log.i("onCreate", "onCreate");
    
    // using onClickListener to prevent being checked automatically by system
    // http://stackoverflow.com/questions/9129858/how-can-i-distinguish-whether-value-is-changed-by-user-or-programmatically-incl
    onOffSwitch.setOnCheckedChangeListener(new OnCheckedChangeListener() {
      
      @Override
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        if (buttonView.isChecked()) {
          if (isWifiEnabled()) {
            Log.i("onCheckedChange", "startTracker");
            startTracker();
          } else {
            Log.i("onCheckedChange", "wifinotenabled message");
            displayWifiNotEnabledMessage();
            onOffSwitch.setChecked(false);
          }
        } else {
          Log.i("onCheckedChange", "stopTracker");
          stopTracker();
        }        
      }
    });
  }

  @Override
  public void onResume() {
    super.onResume();
    if (isTrackerServiceRunning())
    {
      Log.i("onResume", "trackerservice is running");
      onOffSwitch.setChecked(true);
    }
    else {
      Log.i("onResume", "trackerservice is NOT running!!");
      onOffSwitch.setChecked(false);
    }
  }

  @Override
  public void onStart() {
    super.onStart();

    // Register the receiver, to retrieve broadcasts about the Wifi state, from the Android system
    wifiStateReceiver = new WifiStateReceiver();
    registerReceiver(wifiStateReceiver, new IntentFilter(WifiManager.WIFI_STATE_CHANGED_ACTION));
  }

  @Override
  public void onStop() {
    super.onStop();
    unregisterReceiver(wifiStateReceiver);
  }

  // Method for starting the tracker service (with an intent)
  public void startTracker() {    
    //     good explanation of startService/stopService vs bindService/unbindService:
    //     http://stackoverflow.com/questions/3514287/android-service-startservice-and-bindservice
    Intent intent = new Intent(MainActivity.this, com.example.publictransportation.service.TrackerService.class);
    startService(intent);
  }

  public void stopTracker() {
    Intent intent = new Intent(MainActivity.this, com.example.publictransportation.service.TrackerService.class);    
    stopService(intent);
  }

  // used every time we launch the app, to set the UI up correctly
  // CONSIDER: finding a quicker, less intensive way of getting the same info
  private boolean isTrackerServiceRunning() {
    ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
    for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
      if (service.service.getClassName().equals("com.example.publictransportation.service.TrackerService")) {
        return true;
      }
    }
    return false;
  }
  
  @SuppressLint("NewApi")
  private Boolean isWifiEnabled() {
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR2) {
      return (wifiManager.isScanAlwaysAvailable() || wifiManager.isWifiEnabled());
    }
    else {
      return wifiManager.isWifiEnabled();
    }
  }

  private void displayWifiNotEnabledMessage() {
    Toast.makeText(this, getString(R.string.wifiNotEnabledMessage), Toast.LENGTH_SHORT).show();
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
  }

  // Inner class: Receives the broadcasts about the Wifi state, if it's disabled or not
  public class WifiStateReceiver extends BroadcastReceiver {
    @SuppressLint("NewApi")
    public void onReceive(Context context, Intent intent) {
      int wifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, WifiManager.WIFI_STATE_UNKNOWN);

      // disable the service on/off switch when wifi is disabled
      if (wifiState == WifiManager.WIFI_STATE_DISABLED && isTrackerServiceRunning()) {

        // We need to know if API 18/scanning always on mode is available
        // because if it's available, there's no need to switch off the service
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN_MR2){
          onOffSwitch.setChecked(wifiManager.isScanAlwaysAvailable());
        }
        else {
          onOffSwitch.setChecked(false);
        }
      }
    }
  }
}

Java Source Code List

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