判断当前状态是否有网

创建一个 isNetworkAvailable 方法

public boolean isNetworkAvailable(AppCompatActivity appCompatActivity) { Context context = appCompatActivity.getApplicationContext(); ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); if (connectivityManager == null) { return false; } else { NetworkInfo[] networkInfo = connectivityManager.getAllNetworkInfo(); if (networkInfo != null && networkInfo.length > 0) { for (int i = 0; i < networkInfo.length; i++) { if (networkInfo[i].getState() == NetworkInfo.State.CONNECTED) { return true; } } } } return false; }

在需要判断网络的地方写下列代码

//isNetworkAvailable 参数为当前Activity.this if (isNetworkAvailable(MainActivity.this)) { Toast.makeText(getApplicationContext(), "当前有可用网络！", Toast.LENGTH_LONG).show(); } else { Toast.makeText(getApplicationContext(), "当前没有可用网络！", Toast.LENGTH_LONG).show(); }

AndroidManifest.xml 中添加访问当前网络状态权限

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>