请参阅以下代码。当我在我的设备中安装以下代码然后在安装后立即打开程序时,我看到以下结果:
Please Try
但是当我关闭程序并且我想重新打开程序时停止。为什么?问题在哪里?
public class MainActivity extends Activity {
ConnectivityManager connectivityManager;
TextView textView;
NetworkInfo networkInfo;
boolean v;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.textView);
connectivityManager=(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
networkInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
v = networkInfo.isConnected();
if( v == false)
textView.setText("Please Try");
else if(v == true)
textView.setText("Connect");
}
答案 0 :(得分:0)
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
在AndroidManifest.xml文件中添加此行 在此标记之后或之前
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="22" />
或
<application>......</application>