對應一個按鈕 ，點

public class WlActivity extends AppCompatActivity {
Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pdf);
        btn= findViewById(R.id.btn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // https://www.cnblogs.com/guanmanman/p/6769240.html

                if (isNetworkAvailable(WlActivity.this))
                {
                    Toast.makeText(getApplicationContext(), "當前有可用網路！", Toast.LENGTH_LONG).show();
                }
                else
                {
                    Toast.makeText(getApplicationContext(), "當前沒有可用網路！", Toast.LENGTH_LONG).show();
                }

            }
        });


    }



    public boolean isNetworkAvailable(Activity activity)
    {
        Context context = activity.getApplicationContext();
        // 獲取手機所有連線管理物件（包括對wi-fi,net等連線的管理）
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

        if (connectivityManager == null)
        {
            return false;
        }
        else
        {
            // 獲取NetworkInfo物件
            NetworkInfo[] networkInfo = connectivityManager.getAllNetworkInfo();

            if (networkInfo != null && networkInfo.length > 0)
            {
                for (int i = 0; i < networkInfo.length; i++)
                {
                    System.out.println(i + "===狀態===" + networkInfo[i].getState());
                    System.out.println(i + "===型別===" + networkInfo[i].getTypeName());
                    // 判斷當前網路狀態是否為連線狀態
                    if (networkInfo[i].getState() == NetworkInfo.State.CONNECTED)
                    {
                        return true;
                    }
                }
            }
        }
        return false;
    }

}
 

擊對應吐司有沒有忘了，這裡沒有封裝 ，

下面這個對應的簡單 在一個utils類裡面 寫上該方法，直接條用即可

    public static boolean isNetworkAvailable(Context context) {
        ConnectivityManager connectivity = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivity == null) {
            return false;
        } else {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null) {
                for (int i = 0; i < info.length; i++) {
                    if (info[i].getState() == NetworkInfo.State.CONNECTED
                            || info[i].getState() == NetworkInfo.State.CONNECTING) {
                        return true;
                    }
                }
            }
        }
        return false;
    }
 

下面就是對應在activity裡面呼叫 我的是一個button按鈕的點選事件

NdK.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        if (!Util.isNetworkAvailable(GBActivity.this)) {
            Toast.makeText(GBActivity.this,"網路不可用",Toast.LENGTH_LONG).show();
            return;
        }
    }
});