我想用setBackgroundResource()函数设置背景图片,但总是报空指针异常,希望大家帮我看看什么地方有问题
public class BackgroundActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
LinearLayout layout = (LinearLayout)this.findViewById(R.layout.main);
layout.setBackgroundResource(R.drawable.background);
}
}
public class BackgroundActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
LinearLayout layout = (LinearLayout)this.findViewById(R.layout.main);
layout.setBackgroundResource(R.drawable.background);
}
}
这句代码有问题。应该查找xml中定义的LinearLayout 的id
本来layout就有ID了,不用定义。
他明显就是调用自己新实例化那个对象的setBackgroundResource(id);
肯定报错啦!