Ask for permission

app/build.gradle

@@ -6,8 +6,8 @@ android {
         applicationId "tobiass.whatsappcontactgateway"
         minSdkVersion 25
         targetSdkVersion 27
-        versionCode 2
-        versionName "1.0.1"
+        versionCode 3
+        versionName "1.0.2"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
     buildTypes {

app/src/main/java/tobiass/whatsappcontactgateway/EmptyCursor.java

@@ -0,0 +1,216 @@
+package tobiass.whatsappcontactgateway;
+
+import android.content.ContentResolver;
+import android.database.CharArrayBuffer;
+import android.database.ContentObserver;
+import android.database.Cursor;
+import android.database.DataSetObserver;
+import android.net.Uri;
+import android.os.Bundle;
+
+public class EmptyCursor implements Cursor {
+    @Override
+    public int getCount() {
+        return 0;
+    }
+
+    @Override
+    public int getPosition() {
+        return 0;
+    }
+
+    @Override
+    public boolean move(int offset) {
+        return false;
+    }
+
+    @Override
+    public boolean moveToPosition(int position) {
+        return false;
+    }
+
+    @Override
+    public boolean moveToFirst() {
+        return false;
+    }
+
+    @Override
+    public boolean moveToLast() {
+        return false;
+    }
+
+    @Override
+    public boolean moveToNext() {
+        return false;
+    }
+
+    @Override
+    public boolean moveToPrevious() {
+        return false;
+    }
+
+    @Override
+    public boolean isFirst() {
+        return false;
+    }
+
+    @Override
+    public boolean isLast() {
+        return false;
+    }
+
+    @Override
+    public boolean isBeforeFirst() {
+        return false;
+    }
+
+    @Override
+    public boolean isAfterLast() {
+        return false;
+    }
+
+    @Override
+    public int getColumnIndex(String columnName) {
+        return 0;
+    }
+
+    @Override
+    public int getColumnIndexOrThrow(String columnName) throws IllegalArgumentException {
+        return 0;
+    }
+
+    @Override
+    public String getColumnName(int columnIndex) {
+        return null;
+    }
+
+    @Override
+    public String[] getColumnNames() {
+        return new String[0];
+    }
+
+    @Override
+    public int getColumnCount() {
+        return 0;
+    }
+
+    @Override
+    public byte[] getBlob(int columnIndex) {
+        return new byte[0];
+    }
+
+    @Override
+    public String getString(int columnIndex) {
+        return null;
+    }
+
+    @Override
+    public void copyStringToBuffer(int columnIndex, CharArrayBuffer buffer) {
+
+    }
+
+    @Override
+    public short getShort(int columnIndex) {
+        return 0;
+    }
+
+    @Override
+    public int getInt(int columnIndex) {
+        return 0;
+    }
+
+    @Override
+    public long getLong(int columnIndex) {
+        return 0;
+    }
+
+    @Override
+    public float getFloat(int columnIndex) {
+        return 0;
+    }
+
+    @Override
+    public double getDouble(int columnIndex) {
+        return 0;
+    }
+
+    @Override
+    public int getType(int columnIndex) {
+        return 0;
+    }
+
+    @Override
+    public boolean isNull(int columnIndex) {
+        return false;
+    }
+
+    @Override
+    public void deactivate() {
+
+    }
+
+    @Override
+    public boolean requery() {
+        return false;
+    }
+
+    @Override
+    public void close() {
+
+    }
+
+    @Override
+    public boolean isClosed() {
+        return false;
+    }
+
+    @Override
+    public void registerContentObserver(ContentObserver observer) {
+
+    }
+
+    @Override
+    public void unregisterContentObserver(ContentObserver observer) {
+
+    }
+
+    @Override
+    public void registerDataSetObserver(DataSetObserver observer) {
+
+    }
+
+    @Override
+    public void unregisterDataSetObserver(DataSetObserver observer) {
+
+    }
+
+    @Override
+    public void setNotificationUri(ContentResolver cr, Uri uri) {
+
+    }
+
+    @Override
+    public Uri getNotificationUri() {
+        return null;
+    }
+
+    @Override
+    public boolean getWantsAllOnMoveCalls() {
+        return false;
+    }
+
+    @Override
+    public void setExtras(Bundle extras) {
+
+    }
+
+    @Override
+    public Bundle getExtras() {
+        return null;
+    }
+
+    @Override
+    public Bundle respond(Bundle extras) {
+        return null;
+    }
+}

app/src/main/java/tobiass/whatsappcontactgateway/MainActivity.java

@@ -7,13 +7,16 @@
  * @author Tobiaqs
  */
 
+import android.Manifest;
 import android.app.Activity;
 import android.app.LoaderManager;
 import android.content.ContentProvider;
 import android.content.ContentResolver;
+import android.content.Context;
 import android.content.CursorLoader;
 import android.content.Intent;
 import android.content.Loader;
+import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
 import android.database.Cursor;
 import android.net.Uri;
@@ -32,8 +35,11 @@
 
 import java.util.List;
 
-public class MainActivity extends Activity  implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener, FilterQueryProvider, SearchView.OnQueryTextListener {
-    //
+public class MainActivity extends Activity implements AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener, FilterQueryProvider, SearchView.OnQueryTextListener {
+    // constant used when requesting contact permission
+    private static final int PERMISSIONS_REQUEST_READ_CONTACTS = 1;
+
+    // adapter that will provide the contacts cursor to the listview
     private SimpleCursorAdapter mAdapter;
 
     // stuff we want from the contact db
@@ -206,9 +212,28 @@ public boolean onItemLongClick(AdapterView<?> parent, View view, int position, l
         return true;
     }
 
+    @Override
+    public void onRequestPermissionsResult(int requestCode,
+                                           String permissions[], int[] grantResults) {
+        if (requestCode == PERMISSIONS_REQUEST_READ_CONTACTS) {
+            // If request is cancelled, the result arrays are empty.
+            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                mAdapter.getFilter().filter(null);
+            } else {
+                Toast.makeText(this, "Need permission", Toast.LENGTH_SHORT).show();
+            }
+            return;
+        }
+    }
+
     // the method that actually queries the contact db and also filters
     @Override
     public Cursor runQuery(CharSequence constraint) {
+        if (checkSelfPermission(Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
+            requestPermissions(new String[]{ Manifest.permission.READ_CONTACTS }, PERMISSIONS_REQUEST_READ_CONTACTS);
+            return new EmptyCursor();
+        }
+
         ContentResolver cr = getContentResolver();
         String selection = null;
         String[] selectionArgs = null;