erster Click wird nicht "gelistened", aber zweiter schon. warum ?

1public class HelloWorldActivity extends Activity implements OnClickListener {
2
3 private TextView scient;
4 private TextView predict;
5 private TextView histor;
6 private TextView maths;
7
8 /** Called when the activity is first created. */
9 @Override
10 public void onCreate(Bundle savedInstanceState) {
11 super.onCreate(savedInstanceState);
12 setContentView(R.layout.main);
13
14 scient = (TextView) findViewById(R.id.science);
15 scient.setOnClickListener(this);
16
17 predict = (TextView) findViewById(R.id.prediction);
18 predict.setOnClickListener(this);
19
20 histor = (TextView) findViewById(R.id.history);
21 histor.setOnClickListener(this);
22
23 maths = (TextView) findViewById(R.id.maths);
24 maths.setOnClickListener(this);
25
26 }
27
28 @Override
29 public void onClick(View v) {
30 if (v == scient || v == predict || v == maths || v == histor) {
31 scient.setOnClickListener(new View.OnClickListener() {
32 @Override
33 public void onClick(View arg0) {
34 Intent intent = new Intent(getApplicationContext(),
35 Science_view.class);
36 startActivity(intent);
37
38 }
39 });
40
41 predict.setOnClickListener(new View.OnClickListener() {
42 @Override
43 public void onClick(View arg0) {
44 Intent intent = new Intent(getApplicationContext(),
45 Prediction_view.class);
46 startActivity(intent);
47
48 }
49 });
50
51 maths.setOnClickListener(new View.OnClickListener() {
52 @Override
53 public void onClick(View arg0) {
54 Intent intent = new Intent(getApplicationContext(),
55 Maths_view.class);
56 startActivity(intent);
57
58 }
59 });
60
61 histor.setOnClickListener(new View.OnClickListener() {
62 @Override
63 public void onClick(View arg0) {
64 Intent intent = new Intent(getApplicationContext(),
65 History_view.class);
66 startActivity(intent);
67
68 }
69 });
70 }
71 return;
72 }
73}