Android入门程序(ListView包括一个网络状态显示)

为了能够让我们的应用得到网络状态需要在application外部增加权限

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.hello.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="com.example.hello.SystemInfo"> </activity>
    </application>

    <!-- Internet Permissions -->
    <uses-permission android:name="android.permission.INTERNET" />

    <!-- Network State Permissions -->
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

下面我们在MainActivity中增加ListView，并增加ClickListener

public class MainActivity extends Activity {

    private ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        listView = new ListView(this);
        listView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, getData()));


        listView.setOnItemClickListener(new OnItemClickListener(){

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
                ListView listView = (ListView)parent;
                String item = (String) listView.getItemAtPosition(position);
                if (item.equals("SystemInfo"))
                {
                    Intent ii=new Intent();
                    /* 可以向SystemInfo Activity传递数据,这里没有用到 */
                    ii.putExtra("myKey", "value");
                    ii.setClass(MainActivity.this, SystemInfo.class);
                    startActivity(ii);
                }
            }

        });

        setContentView(listView);
    }


    private List<String> getData(){

        List<String> data = new ArrayList<String>();
        data.add("SystemInfo");
        data.add("测试数据2");
        data.add("测试数据3");
        data.add("测试数据4");

        return data;
    }
}

进入SystemInfo Activity

public class SystemInfo extends Activity {

    /* 保存网络状态 */
    private String network_state;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        /* 获取网络状态 */
        ConnectionDetector cd = new ConnectionDetector(getApplicationContext());
        Boolean isInternetPresent;
        isInternetPresent = cd.isConnectingToInternet();
        if (isInternetPresent) {
            network_state = "connecting";
        } else {
            network_state = "disconnect";
        }
        /* 根据res/layout/activity_main.xml中的内容设置TextView内容 */
        ((TextView)findViewById(R.id.network_state)).setText(network_state);
    }
}

获取网络状态部分

/* ConnectionDetector.java */
public class ConnectionDetector {
 
    private Context _context;
 
    public ConnectionDetector(Context context){
        this._context = context;
    }
 
    public boolean isConnectingToInternet(){
        ConnectivityManager connectivity = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
          if (connectivity != null)
          {
              NetworkInfo[] info = connectivity.getAllNetworkInfo();
              if (info != null)
                  for (int i = 0; i < info.length; i++)
                      if (info[i].getState() == NetworkInfo.State.CONNECTED)
                      {
                          return true;
                      }
 
          }
          return false;
    }
}

 源码:http://pan.baidu.com/share/link?shareid=437617&uk=218977851