getting java.lang.NullPointerException: Attempt to invoke virtual method 'int android.content.Context.checkPermission(java.lang.String, int, int)' on a null object reference. My class is
MultiplePermissions
package com.example.phonedetails;
import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.provider.Settings;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;
public class MultiplePermissions extends AppCompatActivity {
Context mContext;
private static final int EXTERNAL_STORAGE_PERMISSION_CONSTANT = 100;
private static final int REQUEST_PERMISSION_SETTING = 101;
private static String[] permissionsRequired = new String[]{Manifest.permission.READ_PHONE_STATE,
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE};
//private TextView txtPermissions;
//private Button btnCheckPermissions;
SharedPreferences permissionStatus;
private boolean sentToSettings = false;
final private Activity activity;
public MultiplePermissions(Activity activity) {
this.activity = activity;
}
public void GetPermissions(){
//permissionStatus = getSharedPreferences("permissionStatus",MODE_PRIVATE);
if(ActivityCompat.checkSelfPermission((MultiplePermissions)mContext, permissionsRequired[0]) != PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission((MultiplePermissions)mContext, permissionsRequired[1]) != PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission((MultiplePermissions)mContext, permissionsRequired[2]) != PackageManager.PERMISSION_GRANTED){
if(ActivityCompat.shouldShowRequestPermissionRationale((MultiplePermissions)mContext,permissionsRequired[0])
|| ActivityCompat.shouldShowRequestPermissionRationale((MultiplePermissions)mContext,permissionsRequired[1])
|| ActivityCompat.shouldShowRequestPermissionRationale((MultiplePermissions)mContext,permissionsRequired[2])){
//Show Information about why you need the permission
AlertDialog.Builder builder = new AlertDialog.Builder(MultiplePermissions.this);
builder.setTitle("Need Multiple Permissions");
builder.setMessage("This app needs Write File and Mobile Details permissions.");
builder.setPositiveButton("Grant", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
ActivityCompat.requestPermissions((MultiplePermissions)mContext,permissionsRequired,EXTERNAL_STORAGE_PERMISSION_CONSTANT);
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
} else if (permissionStatus.getBoolean(permissionsRequired[0],false)) {
//Previously Permission Request was cancelled with 'Dont Ask Again',
// Redirect to Settings after showing Information about why you need the permission
AlertDialog.Builder builder = new AlertDialog.Builder(MultiplePermissions.this);
builder.setTitle("Need Multiple Permissions");
builder.setMessage("This app needs Write File and Mobile Details permissions.");
builder.setPositiveButton("Grant", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
sentToSettings = true;
Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package", getPackageName(), null);
intent.setData(uri);
startActivityForResult(intent, REQUEST_PERMISSION_SETTING);
Toast.makeText(getBaseContext(), "Go to Permissions to Grant Storage and Phone", Toast.LENGTH_LONG).show();
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
} else {
//just request the permission
ActivityCompat.requestPermissions((MultiplePermissions)mContext,permissionsRequired,EXTERNAL_STORAGE_PERMISSION_CONSTANT);
}
//txtPermissions.setText("Permissions Required");
SharedPreferences.Editor editor = permissionStatus.edit();
editor.putBoolean(permissionsRequired[0],true);
editor.commit();
} else {
//You already have the permission, just go ahead.
proceedAfterPermission();
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if(requestCode == EXTERNAL_STORAGE_PERMISSION_CONSTANT){
//check if all permissions are granted
boolean allgranted = false;
for(int i=0;i<grantResults.length;i++){
if(grantResults[i]==PackageManager.PERMISSION_GRANTED){
allgranted = true;
} else {
allgranted = false;
break;
}
}
if(allgranted){
proceedAfterPermission();
} else if(ActivityCompat.shouldShowRequestPermissionRationale((MultiplePermissions)mContext,permissionsRequired[0])
|| ActivityCompat.shouldShowRequestPermissionRationale((MultiplePermissions)mContext,permissionsRequired[1])
|| ActivityCompat.shouldShowRequestPermissionRationale((MultiplePermissions)mContext,permissionsRequired[2])){
//txtPermissions.setText("Permissions Required");
AlertDialog.Builder builder = new AlertDialog.Builder(MultiplePermissions.this);
builder.setTitle("Need Multiple Permissions");
builder.setMessage("This app needs Write File and Mobile Details permissions.");
builder.setPositiveButton("Grant", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
ActivityCompat.requestPermissions((MultiplePermissions)mContext,permissionsRequired,EXTERNAL_STORAGE_PERMISSION_CONSTANT);
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
} else {
Toast.makeText(getBaseContext(),"Unable to get Permission",Toast.LENGTH_LONG).show();
}
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_PERMISSION_SETTING) {
if (ActivityCompat.checkSelfPermission((MultiplePermissions)mContext, permissionsRequired[0]) == PackageManager.PERMISSION_GRANTED) {
//Got Permission
proceedAfterPermission();
}
}
}
private void proceedAfterPermission() {
//txtPermissions.setText("We've got all permissions");
MainActivity.bool=1;
Toast.makeText(getBaseContext(), "We got All Permissions", Toast.LENGTH_LONG).show();
}
@Override
protected void onPostResume() {
super.onPostResume();
if (sentToSettings) {
if (ActivityCompat.checkSelfPermission((MultiplePermissions)mContext, permissionsRequired[0]) == PackageManager.PERMISSION_GRANTED) {
//Got Permission
proceedAfterPermission();
}
}
}
}
i am calling that code from MainActivity and FirstRun like below.
MultiplePermissions permission= new MultiplePermissions(FirstRun.this);
permission.GetPermissions();
my Logcat
01-22 11:39:50.031 29718-29718/com.example.phonedetails E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.phonedetails, PID: 29718
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:430)
at com.example.phonedetails.MultiplePermissions.GetPermissions(MultiplePermissions.java:41)
at com.example.phonedetails.FirstRun$1.onClick(FirstRun.java:46)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
If Know How to fix it please tell me I am beginner.
