在这个应用程序中，我尝试使用片段中的按钮，使用手机的GPS获取片段中的经度和纬度，然后可能将该信息传递给其他片段。
import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.content.ContextCompat;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;
/**
* A simple {@link Fragment} subclass.
*/
public class GalleryFragment extends Fragment {
FragmentActivity mContext = getActivity();
double latitude = 0;//21.6001;
double longitude = 0;//39.136;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final View v = inflater.inflate(R.layout.fragment_gallery, container, false);
Button gpsBtn = (Button) v.findViewById(R.id.gpsBtn);
gpsBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//VVVVVVVVV// HERE IS WHERE THE CRASH HAPPENS...
if (ContextCompat.checkSelfPermission(mContext,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
&& ActivityCompat.checkSelfPermission(mContext,Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(mContext,new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
} else {
Toast.makeText(mContext, "You need have granted permission", Toast.LENGTH_SHORT).show();
GPSTracker gps = new GPSTracker(mContext, GalleryFragment.this);
// Check if GPS enabled
if (gps.canGetLocation()) {
latitude = gps.getLatitude();
longitude = gps.getLongitude();
// \n is for new line
Toast.makeText(getActivity().getApplicationContext(),
"Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
} else {
// Can't get location.
// GPS or network is not enabled.
// Ask user to enable GPS/network in settings.
gps.showSettingsAlert();
}
}
//setMyPrayerList(latitude,longitude,prayerNamez,prayerTimez);
}
});
return v;
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode) {
case 1: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// contacts-related task you need to do.
GPSTracker gps = new GPSTracker(mContext, GalleryFragment.this);
// Check if GPS enabled
if (gps.canGetLocation()) {
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
// \n is for new line
Toast.makeText(getActivity().getApplicationContext(),
"Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
} else {
// Can't get location.
// GPS or network is not enabled.
// Ask user to enable GPS/network in settings.
gps.showSettingsAlert();
}
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
Toast.makeText(mContext, "You need to grant permission", Toast.LENGTH_SHORT).show();
}
}
}
}
}
我是碎片的新手，在我看来，他们可能在很多方面与我刚刚发现的活动如此不同。应用程序正常运行，直到我转到按钮并单击它，此时它崩溃。
下面的是崩溃日志。
谢谢你的时间和帮助。 10-15 05:52:27.500 26041-26041/com.example.majidalashari.sanad E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.majidalashari.sanad, PID: 26041
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.content.Context.checkPermission(java.lang.String, int, int)' on a null object reference
at android.support.v4.content.ContextCompat.checkSelfPermission(ContextCompat.java:432)
at com.example.majidalashari.sanad.GalleryFragment$1.onClick(GalleryFragment.java:43)
at android.view.View.performClick(View.java:5669)
at android.view.View$PerformClick.run(View.java:22546)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6334)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
答案 0 :(得分：0)
How to check permission in fragment
这个链接在@ThetNaingMizo
创建的答案中解决了我的崩溃问题他给出了一个非常明确的愚蠢的例子，说明如何检查Activity Vs Fragment中的权限