我遇到了一个我无法弄清楚的问题。我尝试了很多方法，但没有一个能让我理解为什么它们不起作用。
问题
每次我想运行应用程序时，都会崩溃。在第43行，它说//崩溃在这里。
我要做的是，我有2个带小数输入的textView。
Sry我复制了错误的xml，但它仍然是同一个问题
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<EditText
android:id="@+id/lat"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="My text edit this." >
<requestFocus />
</EditText>
<EditText
android:id="@+id/lng"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="My text edit this."
/>
这是主要：
public class Starter extends Activity implements LocationListener {
protected boolean _active = true;
AlertDialog alertDialog;
int progress = 0;
Location_Finder loc;
protected int _splashTime = 2000;
private Thread splashTread;
public LocationManager lm;
EditText LatText = null;
EditText LongText = null;
double latitude = 18.9599990845;
double longitude = 72.819999694;
public void onCreate(Bundle paramBundle)
{
super.onCreate(paramBundle);
setContentView(R.layout.starter);
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000L, 500.0f, this);
LatText = (EditText) findViewById(R.id.text_lat);
LongText = (EditText) findViewById(R.id.text_lng);
double currentLat = latitude;
double currentLong = longitude;
//Crash here
LatText.setText(Double.toString(currentLat));
LongText.setText(Double.toString(currentLong));
splashTread = new Thread() {
@Override
public void run() {
try {
synchronized(this) {
wait(_splashTime);
}
} catch(InterruptedException e) {
System.out.println("EXc=" + e);
}
finally {
startActivity(new Intent(Starter.this, LocationUpdater.class ));
//stop();
finish();
}
}
};
splashTread.start();
}
/* This method is called when use position will get changed */
public void onLocationChanged(Location loc) {
if (loc != null) {
double lat = loc.getLatitude();
double lng = loc.getLongitude();
String lat_text = ""+ lat + "";
String long_text = ""+ lng + "";
LatText.setText(lat_text);
LongText.setText(long_text);
}
}
public void onProviderDisabled(String provider) {
// required for interface, not used
}
public void onProviderEnabled(String provider) {
// required for interface, not used
}
public void onStatusChanged(String provider, int status, Bundle extras) {
// required for interface, not used
}
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}
LOG
02-11 13:59:16.499: D/AndroidRuntime(10702): Shutting down VM
02-11 13:59:16.499: W/dalvikvm(10702): threadid=1: thread exiting with uncaught exception (group=0x41f592a0)
02-11 13:59:16.504: E/AndroidRuntime(10702): FATAL EXCEPTION: main
02-11 13:59:16.504: E/AndroidRuntime(10702): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.androidhive.jsonparsing/com.androidhive.jsonparsing.Starter}: java.lang.NullPointerException
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.ActivityThread.access$600(ActivityThread.java:140)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.os.Handler.dispatchMessage(Handler.java:99)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.os.Looper.loop(Looper.java:137)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.ActivityThread.main(ActivityThread.java:4898)
02-11 13:59:16.504: E/AndroidRuntime(10702): at java.lang.reflect.Method.invokeNative(Native Method)
02-11 13:59:16.504: E/AndroidRuntime(10702): at java.lang.reflect.Method.invoke(Method.java:511)
02-11 13:59:16.504: E/AndroidRuntime(10702): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
02-11 13:59:16.504: E/AndroidRuntime(10702): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
02-11 13:59:16.504: E/AndroidRuntime(10702): at dalvik.system.NativeStart.main(Native Method)
02-11 13:59:16.504: E/AndroidRuntime(10702): Caused by: java.lang.NullPointerException
02-11 13:59:16.504: E/AndroidRuntime(10702): at com.androidhive.jsonparsing.Starter.onCreate(Starter.java:44)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.Activity.performCreate(Activity.java:5206)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)
02-11 13:59:16.504: E/AndroidRuntime(10702): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
02-11 13:59:16.504: E/AndroidRuntime(10702): ... 11 more
这是必需的
当App启动时，我希望它获取纬度和经度并将其放在textView中，并使用当前位置lat和long值。
答案 0 :(得分：0)
替换
LatText.setText(Double.toString(currentLat));
LongText.setText(Double.toString(currentLong));
与
LatText.setText(String.valueOf(currentLat));
LongText.setText(String.valueOf(currentLong));
答案 1 :(得分：-1)
从你的堆栈跟踪中，我会说LatText为null，因为你没有使用正确的id。
尝试使用xml布局中定义的LatText = (EditText) findViewById(R.id.lat);
OLD ANSWER
我认为你在向后做事：
LocationManager.requestLocationUpdates()可能需要很长时间，您可以使用后台线程来请求位置，并使用runOnUiThread更新TextView或开始新活动。
重要提示：请务必在活动的onPause方法中停止该帖子！