Question

我正在尝试让broadcastReceiver将我的TextView更改为收到短信的邮件正文。当我使用Toast进行警报时，它可以找到，但正如我所说，我希望更改文本视图。应用程序启动但在收到短信时崩溃。请注意，不能直接从扩展broadcastreceiver的类更改textview。所有帮助都表示赞赏：）

这是我的logcat

01-15 02:14:45.714: D/gralloc_goldfish(2551): Emulator without GPU emulation detected.
01-15 02:15:37.165: D/dalvikvm(2551): newInstance failed: no <init>()
01-15 02:15:37.165: D/AndroidRuntime(2551): Shutting down VM
01-15 02:15:37.165: W/dalvikvm(2551): threadid=1: thread exiting with uncaught exception (group=0xb0eca648)
01-15 02:15:37.165: E/AndroidRuntime(2551): FATAL EXCEPTION: main
01-15 02:15:37.165: E/AndroidRuntime(2551): java.lang.RuntimeException: Unable to instantiate receiver com.androidexample.broadcastreceiver.IncomingSms: java.lang.InstantiationException: can't instantiate class com.androidexample.broadcastreceiver.IncomingSms; no empty constructor
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.app.ActivityThread.handleReceiver(ActivityThread.java:2405)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.app.ActivityThread.access$1500(ActivityThread.java:141)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1332)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.os.Looper.loop(Looper.java:137)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.app.ActivityThread.main(ActivityThread.java:5103)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at java.lang.reflect.Method.invokeNative(Native Method)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at java.lang.reflect.Method.invoke(Method.java:525)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at dalvik.system.NativeStart.main(Native Method)
01-15 02:15:37.165: E/AndroidRuntime(2551): Caused by: java.lang.InstantiationException: can't instantiate class com.androidexample.broadcastreceiver.IncomingSms; no empty constructor
01-15 02:15:37.165: E/AndroidRuntime(2551):     at java.lang.Class.newInstanceImpl(Native Method)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at java.lang.Class.newInstance(Class.java:1130)
01-15 02:15:37.165: E/AndroidRuntime(2551):     at android.app.ActivityThread.handleReceiver(ActivityThread.java:2400)

这是IncomingSms类

public class IncomingSms extends BroadcastReceiver {

    final SmsManager sms = SmsManager.getDefault();
    private String senderNum;
    private String message = "No message recieved from bank";
    private TextView textView;

    public IncomingSms(TextView textView) {
        this.textView = textView;
    }

    // Get the object of SmsManager
    public void onReceive(Context context, Intent intent) {

        // Retrieves a map of extended data from the intent.
        final Bundle bundle = intent.getExtras();

        try {

            if (bundle != null) {

                final Object[] pdusObj = (Object[]) bundle.get("pdus");

                for (int i = 0; i < pdusObj.length; i++) {

                    SmsMessage currentMessage = SmsMessage
                            .createFromPdu((byte[]) pdusObj[i]);
                    String phoneNumber = currentMessage
                            .getDisplayOriginatingAddress();

                    senderNum = phoneNumber;
                    message = currentMessage.getDisplayMessageBody();

                    Log.i("SmsReceiver", "senderNum: " + senderNum
                            + "; message: " + message);

                    this.textView.setText(message);

                    int duration = Toast.LENGTH_LONG;
                    Toast toast = Toast.makeText(context, "senderNum: "
                            + senderNum + ", message: " + message, duration);
                    toast.show();


                } // end for loop
            } // bundle is null

        } catch (Exception e) {
            Log.e("SmsReceiver", "Exception smsReceiver" + e);

        }
    }
}

这是我的BroadcastNewSms类

public class BroadcastNewSms extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.androidexample_broadcast_newsms);
        new IncomingSms((TextView) findViewById(R.id.message));
    }

}

Answer 1

您需要根据堆栈跟踪提供无参数构造函数

public IncomingSms() {}

Answer 2

这行代码无效

new IncomingSms((TextView) findViewById(R.id.message));

因为当新的短信出现时，Android会创建IncomingSms类的新实例 - 它不会使用您的实例。

这就是你收到错误的原因 - IncomingSms没有默认构造函数，而且Android无法创建接收器。

您可以添加一个：

public IncomingSms() {
}

但是你没有对TextView的引用。您应该让接收方向任何UI元素广播本地意图（LocalBroadcastManager）以自行更新。

从BroadcastReceiver更改TextView崩溃

2 个答案: