将短信发送到从Firebase实时数据库检索的号码

Question

我想将文本消息发送给数据库中存在的数字。 当在imageView上点击时，应该发送味精。 以下代码位于一个称为Tab33的片段中。 我只是共享ImageView的onClick方法

 @Override
public void onClick(View view) {
    switch (view.getId()){

        case R.id.imageViewPayments:

            Boolean b = checkPermission();

            if(b==true) {
                DBRef.child("Members").addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                        String phn = dataSnapshot.child("memberPhone").getValue(String.class);
                        String no = "+91 ";
                        String cat = no.concat(phn);
                        sms.sendTextMessage(cat, null, "Hey there! We know you enjoy Canteen Food but nobody likes to be in debt and that too for food. Please"  +
                                " pay your Canteen Bill to the earliest and stay a Happy Tummy!", null, null);
                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {

                    }
                });

                Toast.makeText(getContext(),"Message Sent Successfully",Toast.LENGTH_LONG).show();

            }else{
                Snackbar.make(getView(), "Permission to send message NOT granted!", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }

            return;

        case R.id.imageViewToday:





            return;

        case R.id.imageViewCoupon:



            return;

        case R.id.imageViewComposeMessage:
            Snackbar.make(getView(), "Compose Message!", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
            return;

    }

}

private boolean checkPermission()
{
    String permission = Manifest.permission.SEND_SMS;
    int res = getContext().checkCallingOrSelfPermission(permission);
    return (res == PackageManager.PERMISSION_GRANTED);
}

其中DBRef= FirebaseDatabase.getInstance().getReference(); 和sms = SmsManager.getDefault();

Toast出现，然后应用崩溃。

Answer 1

当您使用ValueEventListener加载节点时，您在onDataChange中获得的快照将包含所有匹配的子节点。要访问各个用户节点，您将需要遍历dataSnapshot.getChildren()。

类似的东西：

DBRef.child("Members").addValueEventListener(new ValueEventListener() {
  @Override
  public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
    for (DataSnapshot childSnapshot: dataSnapshot.getChildren()) { 
      String phn = childSnapshot.child("memberPhone").getValue(String.class);
      System.out.println(phn)
    }
  }

  @Override
  public void onCancelled(@NonNull DatabaseError databaseError) {
    throw databaseError.toException(); // don't ignore errors!
  }