我尝试在Java中添加一些常见的TextViews。我假设,当我想使用setText()
方法时,我应该更早地将Java的TextView对象与XML的TextView连接起来——我使用setId()
。
最后,我在使用setId()
的行中得到了NullPointerException。
我的代码:
TextView[] tvQuestion = new TextView[numberOfQuestions];
TextView[] tvAnswer1 = new TextView[numberOfQuestions];
TextView[] tvAnswer2 = new TextView[numberOfQuestions];
TextView[] tvAnswer3 = new TextView[numberOfQuestions];
LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
for (int i = 0; i < numberOfQuestions; i++) {
tvQuestion[i].setId(View.generateViewId()); // NullPointerException!
tvAnswer1[i].setId(View.generateViewId());
tvAnswer2[i].setId(View.generateViewId());
tvAnswer3[i].setId(View.generateViewId());
tvQuestion[i].setLayoutParams(params);
tvAnswer1[i].setLayoutParams(params);
tvAnswer2[i].setLayoutParams(params);
tvAnswer3[i].setLayoutParams(params);
tvQuestion[i].setText(question[i]);
tvAnswer1[i].setText(option1[i]);
tvAnswer2[i].setText(option2[i]);
tvAnswer3[i].setText(option3[i]);
layAll.addView(tvQuestion[i]);
layAll.addView(tvAnswer1[i]);
layAll.addView(tvAnswer2[i]);
layAll.addView(tvAnswer3[i]);
}
编辑:
解决方案:Philipp Jahoda的帖子。
您刚刚为TextViews创建了一个数组数组中的TextViews为null,只要它们未初始化即可。
所以你需要打电话给
tvQuestion[i] = new TextView(Context);
tvAnswer[i] = new TextView(Context);
// and so on ...
// and then later
tvQuestion[i].setId(View.generateViewId());
// and so on ...
在设置ID和其他东西之前。