Question

继承我的代码

如果我发送纯字符串作为文本，它可以正常工作。但是当我尝试发送坐标时，它会崩溃。我也尝试过使用两项活动;我永远不会发短信。

public class ShowLocationActivity extends Activity implements LocationListener {
  private TextView latituteField;
  private TextView longitudeField;
  private LocationManager locationManager;
  private String provider;


/** Called when the activity is first created. */

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_show_location);
    latituteField = (TextView) findViewById(R.id.TextView02);
    longitudeField = (TextView) findViewById(R.id.TextView04);

    // Get the location manager
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    // Define the criteria how to select the locatioin provider -> use
    // default
    Criteria criteria = new Criteria();
    provider = locationManager.getBestProvider(criteria, false);
    Location location = locationManager.getLastKnownLocation(provider);

    // Initialize the location fields
    if (location != null) {
      System.out.println("Provider " + provider + " has been selected.");
      onLocationChanged(location);
    } else {
      latituteField.setText("Location not available");
      longitudeField.setText("Location not available");
    }
    Button c = (Button) findViewById(R.id.button1);
    final EditText recipientTextEdit = (EditText) ShowLocationActivity.this
            .findViewById(R.id.EditView1);
    Location currentlocation = locationManager.getLastKnownLocation(provider);
    final StringBuffer smsBody = new StringBuffer();
    smsBody.append("http://maps.google.com?q="); 
    smsBody.append(currentlocation.getLatitude());
    smsBody.append(",");
    smsBody.append(currentlocation.getLongitude());
    c.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {

            String phoneNo  = recipientTextEdit.getText().toString();;


               try {
                                       SmsManager smsManager = SmsManager.getDefault();
                                        smsManager.sendTextMessage(phoneNo, null, smsBody.toString(), null, null);
                                        Toast.makeText(getApplicationContext(), "Request Sent!",
                                                Toast.LENGTH_LONG).show();
                                    } catch (Exception e) {
                                        Toast.makeText(getApplicationContext(),
                                                " Error, please try again later!",
                                                Toast.LENGTH_LONG).show();
                                        e.printStackTrace();

        }

        }});
  }

  /* Request updates at startup */
  @Override
  protected void onResume() {
    super.onResume();
    locationManager.requestLocationUpdates(provider, 400, 1, this);
  }

  /* Remove the locationlistener updates when Activity is paused */
  @Override
  protected void onPause() {
    super.onPause();
    locationManager.removeUpdates(this);
  }

  @Override
  public void onLocationChanged(Location location) {
    int lat = (int) (location.getLatitude());
    int lng = (int) (location.getLongitude());
    latituteField.setText(String.valueOf(lat));
    longitudeField.setText(String.valueOf(lng));
  }

  @Override
  public void onStatusChanged(String provider, int status, Bundle extras) {
    // TODO Auto-generated method stub

  }

  @Override
  public void onProviderEnabled(String provider) {
    Toast.makeText(this, "Enabled new provider " + provider,
        Toast.LENGTH_SHORT).show();

  }

  @Override
  public void onProviderDisabled(String provider) {
    Toast.makeText(this, "Disabled provider " + provider,
        Toast.LENGTH_SHORT).show();
  }

应用程序在模拟器中崩溃。

我的logcat

03-13 18:09:11.300: E/AndroidRuntime(802): FATAL EXCEPTION: main
03-13 18:09:11.300: E/AndroidRuntime(802): Process: com.example.android.locationapi.simple, PID: 802
03-13 18:09:11.300: E/AndroidRuntime(802): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.locationapi.simple/com.example.android.locationapi.simple.ShowLocationActivity}: java.lang.NullPointerException
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.ActivityThread.access$700(ActivityThread.java:135)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.os.Handler.dispatchMessage(Handler.java:102)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.os.Looper.loop(Looper.java:137)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.ActivityThread.main(ActivityThread.java:4998)
03-13 18:09:11.300: E/AndroidRuntime(802):  at java.lang.reflect.Method.invokeNative(Native Method)
03-13 18:09:11.300: E/AndroidRuntime(802):  at java.lang.reflect.Method.invoke(Method.java:515)
03-13 18:09:11.300: E/AndroidRuntime(802):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
03-13 18:09:11.300: E/AndroidRuntime(802):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
03-13 18:09:11.300: E/AndroidRuntime(802):  at dalvik.system.NativeStart.main(Native Method)
03-13 18:09:11.300: E/AndroidRuntime(802): Caused by: java.lang.NullPointerException
03-13 18:09:11.300: E/AndroidRuntime(802):  at com.example.de.vogella.android.locationapi.simple.ShowLocationActivity.onCreate(ShowLocationActivity.java:59)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.Activity.performCreate(Activity.java:5243)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
03-13 18:09:11.300: E/AndroidRuntime(802):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
03-13 18:09:11.300: E/AndroidRuntime(802):  ... 11 more

Answer 1

由于您正在使用模拟器，问题可能来自以下几行：

Location currentlocation = locationManager.getLastKnownLocation(provider); 
smsBody.append(currentlocation.getLatitude());
smsBody.append(currentlocation.getLongitude());

currentlocation几乎总是为null，因为没有最后的已知位置。如果您像以前的位置一样执行空检查，则不应该崩溃。我错了。

哦，别忘了为模拟器打开GPS。

在一个活动中通过短信发送Gps坐标

1 个答案: