Question

logcat的：

致命异常：IntentService [BMI] 处理：user.com.test2，PID：3377 java.lang.NullPointerException：尝试调用虚方法＆＃39; java.lang.String java.lang.Object.toString（）＆＃39;在null对象引用上 at services.SendBpRecordServer.onHandleIntent（SendBpRecordServer.java:66）在android.app.IntentService $ ServiceHandler.handleMessage（IntentService.java:66）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:148）在android.os.HandlerThread.run（HandlerThread.java:61）

我要做的是：

我使用凌空从服务器获取数据，并使用IntentService在后台进行操作。并且还使用ResultReceiver将数据从服务获取到活动。

UpdateData.class

public class Updatedata extends AppCompatActivity implements MyResultReceiver.Receiver{
    DbHelper dbHelper;
    public MyResultReceiver resultReceiver, resultReceiverBMI, resultReceiverBP;
    ProgressDialog progressDialog;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.notify);
        Log.i("On Creste","Yes");
        dbHelper=new DbHelper(this);
        //before starting further empty all the tables
        dbHelper.emptyTables();
        progressDialog=new ProgressDialog(Updatedata.this);
        progressDialog.setTitle("Fetching Profile Data");
        progressDialog.setMessage("Please Wait...");
        progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        progressDialog.show();
            resultReceiver=new MyResultReceiver(new Handler());
            resultReceiver.setReceiver(this);
            System.out.println("Fetch Diabetes Data Service "+ SendDiabetesRecordServer.TAG);
            Intent intent=new Intent(this, SendDiabetesRecordServer.class);
            intent.putExtra("nameTag","fetch");
            intent.putExtra("receiverTag",resultReceiver);
            startService(intent);
            Log.i("Fetch BMI Data ", SendBmiRecordServer.TAG);
            resultReceiverBMI=new MyResultReceiver(new Handler());
            resultReceiverBMI.setReceiver(this);
            Intent intent1=new Intent(this,SendBmiRecordServer.class);
            intent1.putExtra("nameTag","fetch");
            intent1.putExtra("receiverTagBMI",resultReceiverBMI);
            startService(intent1);
            Log.i("Fetch BP Data ", SendBpRecordServer.TAG);
            resultReceiverBP=new MyResultReceiver(new Handler());
            resultReceiverBP.setReceiver(this);
             Intent intent2=new Intent(this,SendBpRecordServer.class);
             intent2.putExtra("nameTag","fetch");
             intent2.putExtra("receiverTagBP",resultReceiverBP);
             startService(intent2);
        /*if (progressDialog.isShowing()) {
            progressDialog.dismiss();
        }*/
    }
    @Override
    public void onReceiveResult(int resultCode, Bundle resultData) {
        // TODO Auto-generated method stub
        Log.d("Diabetes","received result from Service= "+resultData.getString("ServiceTag"));
        Log.d("BMI ","received result from Service= "+resultData.getString("ServiceTag"));
       /* if (progressDialog.isShowing()) {
            progressDialog.dismiss();
        }*/
        Log.i("Get Values ",Integer.toString(Constants.getValues));
        if (resultCode==0 && resultData.getBoolean("Process_Complete"))
            Constants.getValues++;
        if (resultCode==1 && resultData.getBoolean("Process_Complete_bmi"))
            Constants.getValues++;
        if (resultCode==2 && resultData.getBoolean("Process_Complete_bp"))
            Constants.getValues++;
        if (Constants.getValues==3)
        {
            if (progressDialog.isShowing()) {
                progressDialog.dismiss();
            }
            startActivity(new Intent(this,MainActivity.class));
            finish();
        }
    }
}

IntentService模板：

@Override
protected void onHandleIntent(Intent intent) {

    String recName=intent.getStringExtra("nameTag");

    if (recName.equals("fetch"))
    {


        fetchDatFromServer();

        ResultReceiver resultReceiver=intent.getParcelableExtra("receiverTag");

        Log.d("diabetes Reseult ",resultReceiver.toString());

        Bundle b= new Bundle();
        b.putBoolean("Process_Complete",true);
        resultReceiver.send(0, b);
    }

对于3 IntentService，这是相同的。

获取错误： -

@Override
protected void onHandleIntent(Intent intent) {

    String recName=intent.getStringExtra("nameTag");

    if (recName.equals("fetch"))
    {
        Log.i("Send Data","Yes");
        fetchDatFromServer();

        ResultReceiver resultReceiver=intent.getParcelableExtra("receiverTag");

        **Log.d("BP Reseult ",resultReceiver.toString());**  //Getting Error at this line

        Bundle bun= new Bundle();
        bun.putBoolean("Process_Complete_bp",true);
        resultReceiver.send(2, bun);

    }

调试：

在第二个意图类中，即SendBmiRecordServer.class

我非常确定这个问题只出在这堂课上。因为当我把Log.i("Get Values", Constants.getValues); 我已在Constants.getValues=0

中初始化Constants.class

我得到的结果直到1

Answer 1

试试这个

覆盖onDestroy方法并执行以下操作

 @Override
    public void onDestroy() {
        super.onDestroy();
              if (progressDialog != null && progressDialog.isShowing()) {
                progressDialog.dismiss();
            }
    }

进程对话框

1 个答案: