为什么此程序无法在Android虚拟设备中运行？

Question

WelcomeActivity：

package com.emdad.androidapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;


public class WelcomeActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

        findViewById(R.id.androidButton).setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                Intent intent=new Intent(WelcomeActivity.this, GameActivity.class);
                startActivity(intent);

            }
        });

        setContentView(R.layout.activity_welcome);
    }


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

GameActivity：

package com.emdad.androidapp;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class GameActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_game);
    }

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

当它在Android虚拟设备中运行时，它回答“不幸的是，它已经停止了”。有什么问题？

Answer 1

你应该移动

setContentView(R.layout.activity_welcome);

之前

findViewById(R.id.androidButton).setOnClickListener(new OnClickListener() {

修正：

 setContentView(R.layout.activity_welcome);

 findViewById(R.id.androidButton).setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
        Intent intent=new Intent(WelcomeActivity.this, GameActivity.class);
        startActivity(intent);

    }
});