I am trying to get a simple listview and followed the standard ListView on https://developer.android.com/guide/topics/ui/layout/listview. Only when I press the button in my MainActivity, the app closes and I get the message that you can see in the logcat. I just started programming java and using android studio so there may be something I do that is completely wrong. Does anyone know what my problem is and mayby how to solve it?
My MainActivity:
package com.wouterdesigns.a8383;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = findViewById(R.id.switchbutton);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
switchToListView();
}
});
}
public void switchToListView(){
Intent i = new Intent(this, ListViewLoader.class);
startActivity(i);
}
}
My ListViewLoader:
package com.wouterdesigns.a8383;
import android.app.ListActivity;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.SimpleCursorAdapter;
public class ListViewLoader extends ListActivity
implements LoaderManager.LoaderCallbacks<Cursor> {
// This is the Adapter being used to display the list's data
SimpleCursorAdapter mAdapter;
// These are the Contacts rows that we will retrieve
static final String[] PROJECTION = new String[] {ContactsContract.Data._ID,
ContactsContract.Data.DISPLAY_NAME};
// This is the select criteria
static final String SELECTION = "((" +
ContactsContract.Data.DISPLAY_NAME + " NOTNULL) AND (" +
ContactsContract.Data.DISPLAY_NAME + " != '' ))";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create a progress bar to display while the list loads
ProgressBar progressBar = new ProgressBar(this);
progressBar.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, Gravity.CENTER));
progressBar.setIndeterminate(true);
getListView().setEmptyView(progressBar);
// Must add the progress bar to the root of the layout
ViewGroup root = (ViewGroup) findViewById(android.R.id.content);
root.addView(progressBar);
// For the cursor adapter, specify which columns go into which views
String[] fromColumns = {ContactsContract.Data.DISPLAY_NAME};
int[] toViews = {android.R.id.text1}; // The TextView in simple_list_item_1
// Create an empty adapter we will use to display the loaded data.
// We pass null for the cursor, then update it in onLoadFinished()
mAdapter = new SimpleCursorAdapter(this,
android.R.layout.simple_list_item_1, null,
fromColumns, toViews, 0);
setListAdapter(mAdapter);
// Prepare the loader. Either re-connect with an existing one,
// or start a new one.
getLoaderManager().initLoader(0, null, this);
}
// Called when a new Loader needs to be created
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
// Now create and return a CursorLoader that will take care of
// creating a Cursor for the data being displayed.
return new CursorLoader(this, ContactsContract.Data.CONTENT_URI,
PROJECTION, SELECTION, null, null);
}
// Called when a previously created loader has finished loading
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
// Swap the new cursor in. (The framework will take care of closing the
// old cursor once we return.)
mAdapter.swapCursor(data);
}
// Called when a previously created loader is reset, making the data unavailable
public void onLoaderReset(Loader<Cursor> loader) {
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
mAdapter.swapCursor(null);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Do something when a list item is clicked
}
}
my logcat:
E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.wouterdesigns.a8383, PID: 13242
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:365)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
at java.util.concurrent.FutureTask.run(FutureTask.java:271)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
at java.lang.Thread.run(Thread.java:784)
Caused by: java.lang.SecurityException: Permission Denial: opening provider com.android.providers.contacts.ContactsProvider2 from ProcessRecord{866b18b 13242:com.wouterdesigns.a8383/u0a209} (pid=13242, uid=10209) requires android.permission.READ_CONTACTS or android.permission.WRITE_CONTACTS
at android.os.Parcel.readException(Parcel.java:1945)
at android.os.Parcel.readException(Parcel.java:1891)
at android.app.IActivityManager$Stub$Proxy.getContentProvider(IActivityManager.java:4779)
at android.app.ActivityThread.acquireProvider(ActivityThread.java:6645)
at android.app.ContextImpl$ApplicationContentResolver.acquireUnstableProvider(ContextImpl.java:2798)
at android.content.ContentResolver.acquireUnstableProvider(ContentResolver.java:1820)
at android.content.ContentResolver.query(ContentResolver.java:750)
at android.content.ContentResolver.query(ContentResolver.java:716)
at android.content.CursorLoader.loadInBackground(CursorLoader.java:64)
at android.content.CursorLoader.loadInBackground(CursorLoader.java:54)
at android.content.AsyncTaskLoader.onLoadInBackground(AsyncTaskLoader.java:315)
at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:69)
at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:64)
at android.os.AsyncTask$2.call(AsyncTask.java:345)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
at java.lang.Thread.run(Thread.java:784)
