如何使 for 循环等待事件处理程序完成？ Android

Question

I have a loop which iterates 10 times. Each time I update the question and the choices and check for the correct choice. The thing is, the loop does not wait for setOnClickListner to finish its job. it just ignores it and iterates till the end, Also, if I put the counter inside the listener, it just goes into an infinite loop and the screen turns to dark. How I can overcome this?

Note: the counter has been declared globally.

 for(;counter<10;counter++){
        questionTv.setText(questions[counter]);
        questionImage.setImageResource(images[counter]);
        choice1.setText(choices[counter][0]);
        choice2.setText(choices[counter][1]);
        choice3.setText(choices[counter][2]);
        choice4.setText(choices[counter][3]);
        choice1.setEnabled(true);
        choice2.setEnabled(true);
        choice3.setEnabled(true);
        choice4.setEnabled(true);
        choicesRg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener(){
            @Override
            public void onCheckedChanged(RadioGroup group,int checkedId){
                switch(checkedId){
                    case R.id.choice1:{
                        checkAnswer(answers,choice1,choice2,choice3,choice4,scoreTv); //a method to check the answer and do necessary modification. 
                        break;
                    }
                    case R.id.choice2:{
                        checkAnswer(answers,choice2,choice1,choice3,choice4,scoreTv);
                        break;
                    }
                    case R.id.choice3:{
                        checkAnswer(answers,choice3,choice2,choice1,choice4,scoreTv);
                        break;
                    }
                    case R.id.choice4:{
                        checkAnswer(answers,choice4,choice2,choice3,choice1,scoreTv);
                        break;
                    }
                }
            }
        });
    }

Answer 1

Whipped this up quickly, however, like i said in my comment, there are better ways by design to do what you are doing, without loops, using Android components.

You have a list of questions, and predictably questions go from 1 to 10 (in your case), so lets increment the question number after each time you call checkAnswer and subsequently refresh the view:

private void setQuestions(int questionNum) {
        questionTv.setText(questions[questionNum]);
        questionImage.setImageResource(images[questionNum]);
        choice1.setText(choices[questionNum][0]);
        choice2.setText(choices[questionNum][1]);
        choice3.setText(choices[questionNum][2]);
        choice4.setText(choices[questionNum][3]);
        choice1.setEnabled(true);
        choice2.setEnabled(true);
        choice3.setEnabled(true);
        choice4.setEnabled(true);
        choicesRg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener(){
            @Override
            public void onCheckedChanged(RadioGroup group,int checkedId){
                switch(checkedId){
                    case R.id.choice1:{
                        checkAnswer(answers,choice1,choice2,choice3,choice4,scoreTv, questionNum); //a method to check the answer and do necessary modification.
                        break;
                    }
                    case R.id.choice2:{
                        checkAnswer(answers,choice2,choice1,choice3,choice4,scoreTv, questionNum);
                        break;
                    }
                    case R.id.choice3:{
                        checkAnswer(answers,choice3,choice2,choice1,choice4,scoreTv, questionNum);
                        break;
                    }
                    case R.id.choice4:{
                        checkAnswer(answers,choice4,choice2,choice3,choice1,scoreTv, questionNum);
                        break;
                    }
                }
            }
        });
    }

private void checkAnswer(List<String> answers, 
                         boolean choice1, 
                         boolean choice2, 
                         boolean choice3, 
                         boolean choice4, 
                         TextView scoreTv,
                         int questionNum) {
    // Do stuff
    setQuestions(questionNum++);
}