相关疑难解决方法(0)

我在向XML创建的布局中添加按钮时遇到了问题.这就是我想要实现的目标:

//some class
else {
        startActivity(new Intent(StatisticsScreen.this, ScreenTemperature.class));
}
////

//ScreenTemperatureClass
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    //this is where I call another class that
    //displays a nice graph
    setContentView(new GraphTemperature(getApplicationContext()));

}

我想在Button这个新屏幕上添加一个,以便它显示在图表下方.我已经尝试创建一个LinearLayout视图,然后创建一个Button并将其添加到此视图但我只是得到了NullPointerException...

任何帮助,将不胜感激.谢谢

编辑#1

这是我尝试使用的创建了一个NullPointerException'强制关闭':

Button buybutton;
LinearLayout layout;

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

    setContentView(new GraphTemperature(getApplicationContext()));

    layout = (LinearLayout) findViewById(R.id.statsviewlayout);
    Button buyButton = new Button(this);
    buyButton.setText(R.string.button_back);
    buyButton.setLayoutParams(new LayoutParams(
        ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.WRAP_CONTENT));
    layout.addView(buyButton);

}

这是logcat错误:

ERROR/AndroidRuntime(293): java.lang.RuntimeException: Unable …