Button (invisible) geht nicht

1<Button
2 android:id="@+id/ueber"
3 android:layout_width="100dp"
4 android:layout_height="40dp"
5 android:layout_alignParentBottom="true"
6 android:layout_marginBottom="15dp"
7 android:visibility="invisible"
8 android:onClick="Impressum" />

1package com.example.testapp;
2
3import android.os.Bundle;
4import android.app.Activity;
5import android.view.Menu;
6import android.view.View;
7
8public class MainActivity extends Activity {
9
10 @Override
11 public void onCreate(Bundle savedInstanceState) {
12 super.onCreate(savedInstanceState);
13 setContentView(R.layout.activity_main);
14 }
15
16 @Override
17 public boolean onCreateOptionsMenu(Menu menu) {
18 // Inflate the menu; this adds items to the action bar if it is present.
19 getMenuInflater().inflate(R.menu.main, menu);
20 return true;
21 }
22
23 public void Impressum (View view){
24
25 setContentView(R.layout.philosophie);
26 }
27 }

1package com.example.meintest;
2
3import android.support.v7.app.ActionBarActivity;
4import android.support.v7.app.ActionBar;
5import android.support.v4.app.Fragment;
6import android.os.Bundle;
7import android.view.LayoutInflater;
8import android.view.Menu;
9import android.view.MenuItem;
10import android.view.View;
11import android.view.ViewGroup;
12import android.widget.Button;
13import android.os.Build;
14
15public class StartSeite extends ActionBarActivity {
16
17 Button bphilo;
18
19
20 @Override
21 protected void onCreate(Bundle savedInstanceState) {
22 super.onCreate(savedInstanceState);
23 setContentView(R.layout.activity_start_seite);
24 Button bphilo = (Button) findViewById(R.id.ueber);
25 bphilo.setOnClickListener(new View.OnClickListener(){
26
27 @Override
28 public void onClick(View v) {
29
30 setContentView(R.layout.sophie_philo);
31
32 }
33
34
35
36 });
37 }