I keep getting errors and i dont know why.

1package com.example.counter;
2
3import android.os.Bundle;
4import android.app.Activity;
5import android.view.Menu;
6import android.widget.*;
7
8public class Main extends Activity {
9
10 int counter = 0;
11 Button add,sub;
12 TextView Display;
13
14
15
16 @Override
17 protected void onCreate(Bundle savedInstanceState) {
18 super.onCreate(savedInstanceState);
19 setContentView(R.layout.main);
20 }
21
22 add = (Button) findviewById(R.id.Btnadd);
23
24
25 @Override
26 public boolean onCreateOptionsMenu(Menu menu) {
27 // Inflate the menu; this adds items to the action bar if it is present.
28 getMenuInflater().inflate(R.menu.main, menu);
29 return true;
30 }
31
32}

1<LinearLayout xmlns:android=""
2 xmlns:tools=""
3 android:orientation="vertical"
4 android:layout_width="fill_parent"
5 android:layout_height="fill_parent"
6
7 >
8
9 <TextView
10 android:id="@+id/Tv1"
11 android:layout_width="wrap_content"
12 android:layout_height="wrap_content"
13 android:textSize="45sp"
14 android:layout_gravity="center"
15 android:text="@string/TvDisplay"
16 android:textColor="#5DA2FC" />
17
18 <Button
19
20 android:id="@+id/Btnadd"
21 android:layout_width="250dp"
22 android:layout_height="wrap_content"
23 android:layout_gravity="center_horizontal"
24 android:text="@string/Btn1"
25 />
26
27
28 <Button
29
30 android:id="@+id/Btnsub"
31 android:layout_width="250dp"
32 android:layout_height="wrap_content"
33 android:layout_gravity="center_horizontal"
34 android:text="@string/Btn2"
35 />
36
37
38
39
40
41</LinearLayout>