Question

我想调用从子类到主活动类的函数。这是我的源代码： SMS.java

public class SMS extends ListActivity {
    public void testerr(String kata) {
        Toast.makeText(getBaseContext(), "test coyyyy="+kata, Toast.LENGTH_LONG).show();
    }
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        }
}

SMSReceiver.java

public class SmsReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = intent.getExtras();
        SmsMessage[] msgs = null;
        String str = "";
        try {
            if (bundle != null) {
                Object[] pdus = (Object[]) bundle.get("pdus");
                msgs = new SmsMessage[pdus.length];
                for (int i = 0; i < msgs.length; i++) {
                    msgs[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
                    str += "SMS from " + msgs[i].getOriginatingAddress();
                    str += " :";
                    str += msgs[i].getMessageBody().toString();
                    str += "\n";
                }
                Toast.makeText(context, str, Toast.LENGTH_LONG).show();
                SMS sss = new SMS(); ---> call the main class
                sss.testerr("try the words"); ---> call method from main class
                Toast.makeText(context, str, Toast.LENGTH_LONG).show();
            }
        }
        catch(NullPointerException ex){
            Toast.makeText(context, "penyakite neng kene:"+ex.getMessage(), Toast.LENGTH_LONG).show();
        }
    }
}

我的程序在收到新的文本消息后运行，并且在调用sss.testerr（“我的示例单词”）时总是得到NullPointerException; 任何线索的家伙？非常感谢你的帮助

Answer 1

你不应该用它的构造函数实例化Activity，要么用intent启动它，要么如果Activity已经启动，那就让它实现广播接收器。

如果您只想通过接收器显示吐司，可以使用this question的答案

Java Android：Subclass，来自main活动类的Call方法导致NullPointerException

1 个答案: