小编Diz*_*ley的帖子

我正在尝试使用Google University Android lab1,要求您根据从其他活动通过Intent传递的值更改TextView的文本内容.

我尝试了其余的代码,但是......当我添加"tv.settext(...)行"时,为什么我的应用强行关闭？

public class HelloWorld extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        /*
         * Fetch and display passed string.
         */
        TextView tv = (TextView) findViewById(R.id.HelloTV);
        Bundle extras = this.getIntent().getExtras();
        if (extras != null) {
            String nameStr = extras.get("Username").toString();
            if (nameStr != null) {
                tv.setText("Hello "+nameStr);         
            }
        }
        setContentView(R.layout.main);
    }
}