Question

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");
    }

Answer 1

<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>

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1 个答案: