Question

我正在创建测验应用，当用户选择答案时，我会根据他/她是否正确/不正确来更改单选按钮的背景颜色。我想这样做，暂停在这个部分停留一两秒，然后改变我片段中的问题/答案。问题是，我对我应该暂停的地方感到困惑。通常，我应该在onAnswerSelected()函数（更改我的RadioButtons上的文本）执行之前将暂停放在正确的位置。但是，问题是屏幕上的任何内容都不会更新，直到onCheckedChanged()完成执行。

Fragment.java

    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        List<String> answers = new ArrayList<String>();
        answers.add(answer1);
        answers.add(answer2);
        answers.add(answer3);
        answers.add(answer4);
        Collections.shuffle(answers);
        TextView questionTV = (TextView) getView().findViewById(R.id.question);
        questionTV.setText(question);
        final RadioButton answer1RB = (RadioButton) getView().findViewById(R.id.answer1);
        final RadioButton answer2RB = (RadioButton) getView().findViewById(R.id.answer2);
        final RadioButton answer3RB = (RadioButton) getView().findViewById(R.id.answer3);
        final RadioButton answer4RB = (RadioButton) getView().findViewById(R.id.answer4);
        answer1RB.setText(answers.get(0));
        answer2RB.setText(answers.get(1));
        answer3RB.setText(answers.get(2));
        answer4RB.setText(answers.get(3));
        answer1RB.setChecked(false);
        RadioGroup rg = (RadioGroup) getView().findViewById(R.id.answers);
        rg.setOnCheckedChangeListener(new OnCheckedChangeListener()
        {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId)
            {
                boolean correctAnswerSelected = false;
                switch(checkedId)
                {
                case R.id.answer1:
                    if (answer1RB.getText().equals(answer1)) {
                        answer1RB.setBackgroundColor(Color.GREEN);
                        correctAnswerSelected = true;
                    } else {
                        answer1RB.setBackgroundColor(Color.RED);
                        findCorrectAnswer(answer1RB, answer2RB, answer3RB, answer4RB);
                    }
                    break;
                case R.id.answer2:
                    if (answer2RB.getText().equals(answer1)) {
                        answer2RB.setBackgroundColor(Color.GREEN);
                        correctAnswerSelected = true;
                    } else {
                        answer2RB.setBackgroundColor(Color.RED);
                        findCorrectAnswer(answer1RB, answer2RB, answer3RB, answer4RB);
                    }
                    break;
                case R.id.answer3:
                    if (answer3RB.getText().equals(answer1)) {
                        answer3RB.setBackgroundColor(Color.GREEN);
                        correctAnswerSelected = true;
                    } else {
                        answer3RB.setBackgroundColor(Color.RED);
                        findCorrectAnswer(answer1RB, answer2RB, answer3RB, answer4RB);
                    }
                    break;
                case R.id.answer4:
                    if (answer4RB.getText().equals(answer1)) {
                        answer4RB.setBackgroundColor(Color.GREEN);
                        correctAnswerSelected = true;
                    } else {
                        answer4RB.setBackgroundColor(Color.RED);
                        findCorrectAnswer(answer1RB, answer2RB, answer3RB, answer4RB);
                    }
                    break;
                }
                // Need to execute some sort of pause here, and finish before onAnswerSelected is called
                mCallback.onAnswerSelected(correctAnswerSelected);
            }
        });
    }

QuizTemplate.java

@Override
    public void onAnswerSelected(boolean answeredQuestionCorrectly) {
        PlaceholderFragment fragment = (PlaceholderFragment)getSupportFragmentManager().
                findFragmentById(R.id.container2);
        if (fragment != null) {
            RadioButton answer1 = (RadioButton) fragment.getView().findViewById(R.id.answer1);
            RadioButton answer2 = (RadioButton) fragment.getView().findViewById(R.id.answer2);
            RadioButton answer3 = (RadioButton) fragment.getView().findViewById(R.id.answer3);
            RadioButton answer4 = (RadioButton) fragment.getView().findViewById(R.id.answer4);
            answer1.setText("test");
            answer2.setText("test");
            answer3.setText("test");
            answer4.setText("test");
            answer1.setBackgroundColor(Color.WHITE);
            answer2.setBackgroundColor(Color.WHITE);
            answer3.setBackgroundColor(Color.WHITE);
            answer4.setBackgroundColor(Color.WHITE);
            answer1.setChecked(false);
            answer2.setChecked(false);
            answer3.setChecked(false);
            answer4.setChecked(false);
        }

Answer 1

使用线程和runnable。睡眠线程暂停，然后更新UI。

示例代码：

new Thread(new Runnable() {

        @Override
        public void run() {

            try {
                //pause for 5 seconds
                Thread.sleep(1000*5);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            getActivity().runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    // update your UI here
                     mCallback.onAnswerSelected(correctAnswerSelected);
                }
            });
        }
    }).start();

如何做两件需要UI在onCheckedChanged（）内更新的东西？

1 个答案: