ListView

[seaside]

Hallo zusammen,

ich bin absoluter Neuling in der Android Programmierung und sitze gerade an einer recht simplen App. Die App soll über eine Liste, eine EditText-Feld und einem Suchen-Button verfügen.
Ein einzelnes Listenelement soll aus zwei Strings (zwei TextViews) bestehen.

Das EditText-Feld und der Button werden angezeigt die Liste jedoch nicht.
Ich weiß leider nicht woran es liegt. Vielleicht findet von euch ja jemand den Fehler

Hier der Code:
activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="@string/suchen" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:text="@string/suchen" />
    
    <ListView 
        android:id="@+id/listView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/editText"/>

</RelativeLayout>

itemlayout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
    <TextView
        android:id="@+id/Name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    
     <TextView
        android:id="@+id/Grad"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/Name" />

</RelativeLayout>

item.java

public class Item {
	
	public String name, grad;
	
	public Item(String _name, String _grad){
		this.name = _name;
		this.grad = _grad;
	}

}

MainActivity.java

import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class MainActivity extends Activity {

	public ArrayList<Item> datensaetze;
	Adapter myAdapter;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		init();
		
		ListView listView = (ListView) findViewById(R.id.listView);
		myAdapter = new Adapter();
		listView.setAdapter(myAdapter);
		
		
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.activity_main, menu);
		return true;
	}

	public void init(){
		datensaetze = new ArrayList<Item>();
		datensaetze.add(new Item("Aal", "Keine"));
		datensaetze.add(new Item("Agar-Agar", "Sehr stark"));
		datensaetze.add(new Item("Amaranth", "Keine"));
	}
	
	public class Adapter extends BaseAdapter {

		LayoutInflater mInflater;
		
		
		@Override
		public int getCount() {
			return datensaetze.size();
		}

		@Override
		public Object getItem(int position) {
			return datensaetze.get(position);
		}

		@Override
		public long getItemId(int position) {
			return position;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			
			if(convertView == null){
				convertView = mInflater.inflate(R.layout.itemlayout, parent, false);
			
			}
			TextView nameTextView = (TextView) convertView.findViewById(R.id.Name);
			TextView gradTextView = (TextView) convertView.findViewById(R.id.Grad);
			
			Item item = (Item) getItem(position);
			nameTextView.setText(item.name);
			gradTextView.setText(item.grad);
			
			return convertView;
		}
		
	}
}

Vielen Dank schon mal