我用2个单选按钮动态创建了2个无线电组。每个单选按钮代表一个问题的答案。我使用setOnCheckedChangeListener来查看哪些anwsers是正确的。因此,当我按下按钮时,我希望拥有所有广播组clearCheck()
以及正确答案setTextColor(Color.GREEN)
。使用此代码,当我使用radioGroup[i].clearCheck();
时,我收到此错误:Attempt to invoke virtual method 'java.lang.Object android.widget.RadioButton.getTag()' on a null object reference
。我怎样才能解决这个问题?我怎样才能将文字颜色设置为绿色,只有正确的答案?这是我的代码:
radioGroup[i].setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
RadioButton checkedRadioButton = (RadioButton)group.findViewById(checkedId);
int CorrectAnswer = Integer.parseInt(checkedRadioButton.getTag().toString());
switch (checkedId) {
case 0:
if (CorrectAnswer == 1) {
Toast.makeText(getApplicationContext(), "You clicked the correct answer ", Toast.LENGTH_SHORT).show();
score++;
} else {
Toast.makeText(getApplicationContext(), "You clicked the incorrect answer ", Toast.LENGTH_SHORT).show();
}
break;
case 1:
if (CorrectAnswer == 1) {
Toast.makeText(getApplicationContext(), "You clicked the correct answer ", Toast.LENGTH_SHORT).show();
score++;
} else {
Toast.makeText(getApplicationContext(), "You clicked the incorrect answer ", Toast.LENGTH_SHORT).show();
}
break;
}
}
});
resetButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
for (int i = 0; i < radioGroup.length; i++) {
radioGroup[i].clearCheck(); // doesn't work
for (int j = 0; j < answer.length; j++) {
radioGroup[i].getChildAt(j).setBackgroundColor(Color.WHITE);
((RadioButton) radioGroup[i].getChildAt(j)).setTextColor(Color.GREEN);
}
}
}
});
谢谢!
答案 0 :(得分:0)
在调用onCheckedChanged
方法时,可能会调用clearCheck
方法,因此在null
方法上调用onCheckedChanged
方法之前,请先toString()
加入setTag
:
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
RadioButton checkedRadioButton = (RadioButton)group.findViewById(checkedId);
if(checkedRadioButton!=null)
if(checkedRadioButton.getTag() !=null){
int CorrectAnswer = Integer.parseInt(
checkedRadioButton.getTag().toString());
....your code here
}
}