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我已經從菜單調用了wifi_refresh（）來自動更新wifi信息，但是，這樣，顯示屏上就沒有任何東西顯示出來。但是，當我使用按鈕刷新時，一切正常。任何人幫助？如何更新內容查看
package com.wifi_info;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import android.app.Activity;
import android.content.Context;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import android.view.MenuItem.OnMenuItemClickListener;
import java.util.concurrent.*;
public class Wifi_infoActivity extends Activity {
/** Called when the activity is first created. */
int update_freq =1;
MenuItem auto_check;
MenuItem view_cg;
MenuItem view_apl;
MenuItem view_sm;
MenuItem set_1;
MenuItem set_3;
MenuItem set_5;
MenuItem set_10;
MenuItem view_menu;
MenuItem settings_menu;
int interval = 1000;
boolean checked = false;
ScheduledThreadPoolExecutor exet = new ScheduledThreadPoolExecutor(5);// not sure about the number
ScheduledFuture<?> handler;
Button refreshButton;
//------------------------------------wifi_refresh---------------------------------------------
WifiManager wifi;
ArrayAdapter<String> aa;
int layoutID = android.R.layout.simple_list_item_1;
ArrayList<String> wifi_info;
int result_size;
String channel;
ListView lv;
List<ScanResult> results;
// --------------------------------------- wifi_refresh- --------------------------------------------
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
wifi_refresh();
refreshButton = (Button)findViewById(R.id.refreshbutton);
refreshButton.setOnClickListener(new OnClickListener(){
public void onClick(View arg0){
wifi_refresh();
}
});
}
public void onStop(){
super.onStop();
exet.shutdownNow();
}
@Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
view_menu = menu.findItem(R.id.view);
settings_menu = menu.findItem(R.id.settings);
auto_check=menu.findItem(R.id.set_check);
if (checked == false)
auto_check.setChecked(false);
else
auto_check.setChecked(true);
view_cg = menu.findItem(R.id.view_cg);
view_apl = menu.findItem(R.id.view_apl);
view_sm = menu.findItem(R.id.view_sm);
set_1 = menu.findItem(R.id.set_1);
set_3 = menu.findItem(R.id.set_3);
set_5 = menu.findItem(R.id.set_5);
set_10 = menu.findItem(R.id.set_10);
view_menu.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
return true;
}
});
settings_menu.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
return true;
}
});
view_cg.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
//show channel graph
return true;
}
});
view_apl.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
wifi_refresh();
return true;
}
});
view_sm.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
//show sm
return true;
}
});
auto_check.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
if(checked==false){
auto_check.setChecked(true);
checked = true;
set_1.setCheckable(true);
set_3.setCheckable(true);
set_5.setCheckable(true);
set_10.setCheckable(true);
showChosen();
schedule_task();
}else{
auto_check.setChecked(false);
checked = false;
set_1.setCheckable(false);
set_3.setCheckable(false);
set_5.setCheckable(false);
set_10.setCheckable(false);
}
return true;
}
});
set_1.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
if(checked==true){
showChosen();
update_freq=1;
showChosen();
reschedule();
}
return true;
}
});
set_3.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
if(checked==true){
showChosen();
update_freq=3;
showChosen();
reschedule();
}
return true;
}
});
set_5.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
if(checked==true){
showChosen();
update_freq=5;
showChosen();
reschedule();
}
return true;
}
});
set_10.setOnMenuItemClickListener(new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item){
if(checked==true){
showChosen();
update_freq=10;
showChosen();
reschedule();
}
return true;
}
});
return true;
}
public boolean showChosen(){
switch(update_freq){
case(1):{
set_1.setChecked(true);break;
}
case(3):{
set_3.setChecked(true);break;
}
case(5):{
set_5.setChecked(true);break;
}
case(10):{
set_10.setChecked(true);break;
}
}return true;
}
public void onClick(String n) {
Toast.makeText(Wifi_infoActivity.this,n,
Toast.LENGTH_SHORT).show();
}
public void schedule_task(){
Runnable task = new Runnable(){
public void run(){
wifi_refresh();
}
};
handler = exet.scheduleWithFixedDelay(task,0, interval, TimeUnit.MILLISECONDS);
}
public void reschedule(){
while(interval!=(update_freq*1000)){
handler.cancel(true);
interval = update_freq*1000;
handler = exet.scheduleWithFixedDelay(new Runnable(){
public void run(){
wifi_refresh();
}
}, 0, interval, TimeUnit.MILLISECONDS);
}
}
public void wifi_refresh(){
wifi_info = new ArrayList<String>();
result_size =0;
channel = "";
lv = (ListView)findViewById (R.id.myListView);
wifi = (WifiManager)getSystemService(Context.WIFI_SERVICE);
if(!wifi.isWifiEnabled())
if(wifi.getWifiState()!=WifiManager.WIFI_STATE_ENABLING)
wifi.setWifiEnabled(true);
wifi.startScan();
results = wifi.getScanResults();
result_size = results.size();
for(int j =0;j<result_size;j++){
String mystring = new String();
ScanResult result = results.get(j);
switch (result.frequency) {
case 2412: channel = "1"; break;
case 2417: channel = "2"; break;
case 2422: channel = "3"; break;
case 2427: channel = "4"; break;
case 2432: channel = "5"; break;
case 2437: channel = "6"; break;
case 2442: channel = "7"; break;
case 2447: channel = "8"; break;
case 2452: channel = "9"; break;
case 2457: channel = "10"; break;
case 2462: channel = "11"; break;
case 2467: channel = "12"; break;
case 2472: channel = "13"; break;
case 2484: channel = "14"; break;
}
mystring = String.format("SSID: %s, Level: %s, Authentication: %s, BSSID: %s, Frequency:%s MHz, Channel:%s", result.SSID.toString(), result.level, result.capabilities.toString(),result.BSSID.toString(), result.frequency, channel);
wifi_info.add(j, mystring);
channel = "";
}
aa = new ArrayAdapter<String>(this,layoutID, wifi_info);
lv.setAdapter(aa);
}
}
謝謝，這個作品！ – user301