要崩溃了，两个Activity没法跳转，什么错都不报，3天了系统都重装了

package my.android;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;public class MyAndroidActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        TextView tvTextView=(TextView) findViewById(R.id.mytv);        tvTextView.setText("wo cao");        Button btnButton=(Button) findViewById(R.id.mybutton);        btnButton.setText("my button");        btnButton.setOnClickListener(new android.view.View.OnClickListener() {            @Override            public void onClick(View v) {                // TODO Auto-generated method stub            //    MyAndroidActivity.this.finish();                Intent intent=new Intent();                intent.putExtra("key", "zai cao");                intent.setClass(MyAndroidActivity.this, ActivityTwo.class);                MyAndroidActivity.this.startService(intent);            //    MyAndroidActivity.this.finish();            }        });    }    /*  class MyButtonLN implements android.view.View.OnClickListener{            @Override            public void onClick(View v) {                // TODO Auto-generated method stub                Intent intent=new Intent();                intent.setClass(MyAndroidActivity.this, ActivityTwo.class);                MyAndroidActivity.this.startService(intent);            }                   }  */}

package my.android;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.TextView;public class ActivityTwo extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.two);        Intent thisintent=getIntent();        String keyValue=thisintent.getStringExtra("key");        TextView tvTextView=(TextView) findViewById(R.id.twotv);        tvTextView.setText(keyValue);     }  }

package my.android;public final class R {    public static final class attr {    }    public static final class drawable {        public static final int ic_launcher=0x7f020000;    }    public static final class id {        public static final int mybutton=0x7f050001;        public static final int mytv=0x7f050000;        public static final int twotv=0x7f050002;    }    public static final class layout {        public static final int main=0x7f030000;        public static final int two=0x7f030001;    }    public static final class string {        public static final int app_name=0x7f040001;        public static final int hello=0x7f040000;    }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <TextView        android:id="@+id/mytv"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/hello" />    <Button         android:id="@+id/mybutton"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/hello" /></LinearLayout>