Implementieren von LoaderCallbacks in Activity Android
Ich bin neu in Android. Ich möchte bekommencontacts
Daten mitloaderCallbacks
Ich schreibe Code, aber hier ist ein Problem. Ich weiß nicht, warum das passiert. Kannst du das bitte überprüfen?
package com.example.arfan.myfirstapp;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportLoaderManager().initLoader(1, null, this); // ERROR IS HERE in 3rd Argument
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
Uri CONTENT_URI = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
return new CursorLoader(this, CONTENT_URI, null, null, null, null);
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
Log.i("INFO","This is working");
while(data.moveToNext()){
Log.i("Cantacts : ",data.getString(data.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME)));
}
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
}
}
Es gibt irgendeine Art von Problem inthis
Streit. Wenn ich diese Zeile entferne, tritt kein Fehler auf und ich habe auch kein Ergebnis gefunden. Ich habe diesen Code von einer Website gelesen, wie man Kontaktdaten in Android bekommGo to Site
Können Sie mir bitte mitteilen, wo das Problem liegt und wie ich es beheben kann. Vielen Dank
AKTUALISIEREN Konsole zeigt dies.
Error:(25, 34) error: method initLoader in class LoaderManager cannot be applied to given types;
required: int,Bundle,LoaderCallbacks<D>
found: int,<null>,MainActivity
reason: cannot infer type-variable(s) D
(argument mismatch; MainActivity cannot be converted to LoaderCallbacks<D>)
where D is a type-variable:
D extends Object declared in method <D>initLoader(int,Bundle,LoaderCallbacks<D>)