1
我有一個MapActivity其中首先嚐試獲取用戶的當前位置。爲了獲取當前位置，我使用了AsyncTask概念。現在我試圖實現的是向用戶顯示ProgressDialog直到獲得當前位置。
這裏是佈局代碼： -
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFFFFF"
android:orientation="vertical" >
<com.google.android.maps.MapView
android:id="@+id/mapview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:apiKey="0nO35c3MpXJisxsknk_w_fqVQa78sPhMQK3Yf5w"
android:clickable="true" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<SeekBar
android:id="@+id/zoombar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:max="20"
android:progress="0" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="70dip"
android:layout_marginTop="5dip"
android:background="@drawable/round"
android:orientation="horizontal" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:padding="5dip" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/sun" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|center_horizontal"
android:layout_marginLeft="15dip" >
<ImageView
android:id="@+id/rupee"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/rupee" />
<TextView
android:id="@+id/day_amount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|right"
android:layout_marginLeft="10dip"
android:numeric="decimal"
android:text="0.0"
android:textColor="@color/autoText"
android:textSize="@dimen/text_size_medium"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
<View
android:layout_width="2dip"
android:layout_height="wrap_content"
android:background="#ff6600" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:padding="5dip" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/moon" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|center_horizontal"
android:layout_marginLeft="15dip" >
<ImageView
android:id="@+id/rupee"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/rupee" />
<TextView
android:id="@+id/night_amount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical|right"
android:layout_marginLeft="10dip"
android:numeric="decimal"
android:text="0.0"
android:textColor="@color/autoText"
android:textSize="@dimen/text_size_medium"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
MapActivity代碼： -
// Background AsyncTask Class
class CurrentPositionTask extends AsyncTask<String, Void, Void> {
boolean flag = true;
@Override
public void onPreExecute() {
// TODO Auto-generated method stub
System.out.println("Executed");
// TODO Auto-generated method stub
dialog = new ProgressDialog(AutoMapActivity.this.getApplicationContext());
dialog.setTitle("");
dialog.setMessage("Searching");
dialog.show();
}
@Override
public Void doInBackground(String... params) {
// TODO Auto-generated method stub
while(flag){
//System.out.println("While Loop");
if (latitude != 0 && longitude != 0) {
flag = false;
break;
}
}
return null;
}
@Override
public void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
locationManager.removeUpdates(locationListener);
if (latitude!=0 && longitude!=0) {
dialog.cancel();
setInit();
}
}
}
//LocationListner Class
class MyLocationListener implements LocationListener {
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "Gps Disabled",
Toast.LENGTH_LONG).show();
}
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "Gps Enabled",
Toast.LENGTH_SHORT).show();
}
public void onStatusChanged(String provider, int status, Bundle extra) {
// TODO Auto-generated method stub
switch (status) {
case 0:
// OutofService
Toast.makeText(getApplicationContext(), "Out of Service",
Toast.LENGTH_LONG).show();
break;
case 1:
// Temporarily unavailable
Toast.makeText(getApplicationContext(),
"Location Temporary Unavailable", Toast.LENGTH_LONG)
.show();
break;
case 2:
// Available
Toast.makeText(getApplicationContext(), "Available",
Toast.LENGTH_LONG).show();
break;
}
}
}
LOG CAT： -'
07-17 19:37:49.267: W/System.err(881): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
07-17 19:37:49.277: W/System.err(881): at android.view.ViewRoot.setView(ViewRoot.java:531)
07-17 19:37:49.277: W/System.err(881): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
07-17 19:37:49.277: W/System.err(881): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
07-17 19:37:49.277: W/System.err(881): at android.app.Dialog.show(Dialog.java:241)
07-17 19:37:49.277: W/System.err(881): at com.test.fare.AutoMapActivity$CurrentPositionTask.onPreExecute(AutoMapActivity.java:195)
07-17 19:37:49.277: W/System.err(881): at android.os.AsyncTask.execute(AsyncTask.java:391)
07-17 19:37:49.277: W/System.err(881): at com.test.fare.AutoMapActivity.getUserCurrentLocation(AutoMapActivity.java:146)
07-17 19:37:49.277: W/System.err(881): at com.test.fare.AutoMapActivity.onCreate(AutoMapActivity.java:80)
07-17 19:37:49.277: W/System.err(881): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-17 19:37:49.287: W/System.err(881): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
07-17 19:37:49.287: W/System.err(881): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
07-17 19:37:49.287: W/System.err(881): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
07-17 19:37:49.287: W/System.err(881): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
07-17 19:37:49.287: W/System.err(881): at android.os.Handler.dispatchMessage(Handler.java:99)
07-17 19:37:49.287: W/System.err(881): at android.os.Looper.loop(Looper.java:130)
07-17 19:37:49.287: W/System.err(881): at android.app.ActivityThread.main(ActivityThread.java:3683)
07-17 19:37:49.297: W/System.err(881): at java.lang.reflect.Method.invokeNative(Native Method)
07-17 19:37:49.297: W/System.err(881): at java.lang.reflect.Method.invoke(Method.java:507)
07-17 19:37:49.297: W/System.err(881): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
07-17 19:37:49.297: W/System.err(881): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
07-17 19:37:49.297: W/System.err(881): at dalvik.system.NativeStart.main(Native Method)
太好了。它的工作現在很好。你能告訴我爲什麼使用getApplicationContext（）時給出錯誤？ – Scorpion 2012-07-17 16:07:13
該對話框綁定到此特定活動，而不是整個應用程序。當創建範圍僅僅是活動的對象時，通常使用Activity.this。在創建範圍超出當前活動範圍的對象時使用應用程序上下文。 – 2012-07-18 06:15:56
嗯。謝謝你告訴我這件事。我知道這個概念，但沒有想到這一點。再一次感謝... – Scorpion 2012-07-18 06:19:17