[Android] – Scan for Wireless Networks


package com.android.wifitester;

import java.util.List;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

public class WifiTester extends Activity {
TextView mainText;
WifiManager mainWifi;
WifiReceiver receiverWifi;
List<ScanResult> wifiList;
StringBuilder sb = new StringBuilder();

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mainText = (TextView) findViewById(R.id.mainText);
mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
receiverWifi = new WifiReceiver();
registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
mainWifi.startScan();
mainText.setText("\\nStarting Scan...\\n");
}

public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0, 0, 0, "Refresh");
return super.onCreateOptionsMenu(menu);
}

public boolean onMenuItemSelected(int featureId, MenuItem item) {
mainWifi.startScan();
mainText.setText("Starting Scan");
return super.onMenuItemSelected(featureId, item);
}

protected void onPause() {
unregisterReceiver(receiverWifi);
super.onPause();
}

protected void onResume() {
registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
super.onResume();
}

class WifiReceiver extends BroadcastReceiver {
public void onReceive(Context c, Intent intent) {
sb = new StringBuilder();
wifiList = mainWifi.getScanResults();
for(int i = 0; i < wifiList.size(); i++){
sb.append(new Integer(i+1).toString() + ".");
sb.append((wifiList.get(i)).toString());
sb.append("\\n");
}
mainText.setText(sb);
}
}
}

[Android] – Prompt User Input with an AlertDialog


AlertDialog.Builder alert = new AlertDialog.Builder(this);

alert.setTitle("Title");
alert.setMessage("Message");

// Set an EditText view to get user input
final EditText input = new EditText(this);
alert.setView(input);

alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
String value = input.getText();
// Do something with value!
}
});

alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// Canceled.
}
});

alert.show();

[Android] – Check if internet is available


/*
* @return boolean return true if the application can access the internet
*/
private boolean haveInternet(){
NetworkInfo info = ((ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();
if (info==null || !info.isConnected()) {
return false;
}
if (info.isRoaming()) {
// here is the roaming option you can change it if you want to disable internet while roaming, just return false
return true;
}
return true;
}

[Android] – Handle Touch Events (onTouchEvent)


public boolean onTouchEvent(MotionEvent event) {
int eventaction = event.getAction();

switch (eventaction) {
case MotionEvent.ACTION_DOWN:
// finger touches the screen
break;

case MotionEvent.ACTION_MOVE:
// finger moves on the screen
break;

case MotionEvent.ACTION_UP:
// finger leaves the screen
break;
}

// tell the system that we handled the event and no further processing is required
return true;
}