当我按“否”(这是 AlertDialog.Builder 的 builder.setNegative 按钮)时,它给了我一个错误:
02-02 22:05:44.360: E/AndroidRuntime(18022): FATAL EXCEPTION: main
02-02 22:05:44.360: E/AndroidRuntime(18022): android.content.ActivityNotFoundException:
Unable to find explicit activity class {com.mamun.tasktest/com.mamun.tasktest
.FragmentB}; have you declared this activity in your AndroidManifest.xml?
当我在清单中添加 FragmentB 时,它还会给出另一个错误:
02-02 22:20:34.030: E/AndroidRuntime(18671): FATAL EXCEPTION: main
02-02 22:20:34.030: E/AndroidRuntime(18671): java.lang.RuntimeException: Unable to
instantiate activity ComponentInfo{com.mamun.tasktest/com.mamun.tasktest
.FragmentB}: java.lang.ClassCastException: com.mamun.tasktest.FragmentB cannot be
cast to android.app.Activity
MapActivity.java:
package com.mamun.tasktest;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.LocationManager;
import android.os.Bundle;
import android.provider.Settings;
public class MapActivity extends Activity{
private LocationManager manager;
@Override
protected void onCreate(Bundle savedInstanceState) {
manager = (LocationManager)getSystemService(LOCATION_SERVICE);
super.onCreate(savedInstanceState);
if(manager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
setContentView(R.layout.map);
}
else if (!manager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("GPS is currently disabled");
builder.setMessage("Please enable it to select location.\nWould you like to change these settings now?");
builder.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent i = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(i);
setContentView(R.layout.map);
}
});
builder.setNegativeButton("No",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent in = new Intent(MapActivity.this,FragmentB.class);
startActivity(in);
}
});
builder.create().show();
}
}
}
片段B.java
package com.mamun.tasktest;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.LocationManager;
import android.os.Bundle;
import android.provider.Settings;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
public class FragmentB extends Fragment implements OnClickListener {
private Button btnLocation;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.frag_b, null, false);
btnLocation = (Button) view.findViewById(R.id.btnLocation);
btnLocation.setOnClickListener(this);
return view;
}
@Override
public void onClick(View v) {
if(isMapAvailalble())
{
Intent in = new Intent(getActivity(),MapActivity.class);
startActivity(in);
}
}
public boolean isMapAvailalble()
{
int resultcode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity());
if(ConnectionResult.SUCCESS==resultcode)
{
return true;
}
else if(GooglePlayServicesUtil.isUserRecoverableError(resultcode))
{
Dialog d = GooglePlayServicesUtil.getErrorDialog(resultcode, getActivity(), 1);
d.show();
}
else
{
Toast.makeText(getActivity()," Google Map API is not supported in your device",Toast.LENGTH_LONG).show();
}
return false;
}
}