求解下面安卓程序运行停止问题，下面是logcat和代码

package com.example.activitylifecycletest;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;

public class MainActivity extends Activity {

public static final String TAG="MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
Log.d(TAG,"onCreate");
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
Button startNormalActivity=(Button) findViewById(R.id.start_normal_activity);
Button startDialogActivity=(Button) findViewById(R.id.start_dialog_activity);
startNormalActivity.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v){
Intent intent=new Intent(MainActivity.this,NormalActivity.class);
startActivity(intent);
}
});
startDialogActivity.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v){
Intent intent=new Intent(MainActivity.this,DialogActivity.class);
startActivity(intent);
}
});
}

    @Override
    protected void onStart(){
    super.onStart();
    Log.d(TAG, "onStart");
    }

    @Override
    protected void onResume(){
    super.onStart();
    Log.d(TAG, "onResume");
    }

    @Override
    protected void onPause(){
    super.onStart();
    Log.d(TAG, "onPause");
    }


    @Override
    protected void onStop(){
    super.onStart();
    Log.d(TAG, "onStop");
    }

    @Override
    protected void onDestroy(){
    super.onStart();
    Log.d(TAG, "onDestroy");
    }

    @Override
    protected void onRestart(){
    super.onStart();
    Log.d(TAG, "onRestart");
    }



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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

}

看一下startDialogActivity 这个，在activity_main布局文件中，你id有没一致

根据日志大概是空指针异常，具体你看错误提示在哪一行

Log日志中倒数第6行有Caused by错误原因，空指针异常 。下面一行有提示在第25行的错误，在OnCreat方法中。

line 25 空指针异常，请核查改行的代码

检查一下activity_maind这个布局文件里面有没有start_normal_activity，start_dialog_activity这两个Button