所以，我正在创建一个用于学习目的的小琐事游戏，但我遇到了一个问题。
首先，我有一个特定的Android Fragment从JSON获取数据，我将简单地在回调方法上使用该数据并将其显示在TextViews和Buttons上。一切都很好，但是，每次我回到那个片段时，都会有同样的问题。所以我决定在回调方法之外以更好的方式处理它。
这里的问题是显然我的Arrays是null或者它们的长度是零。这很奇怪，因为根据我的LOG，数据正在回调方法上传递给那些数组。
这是我的完整片段代码。谢谢！
public class GameFragment extends Fragment {
private TextView txtQuestion;
private Button btnAnswer1;
private Button btnAnswer2;
private Button btnAnswer3;
private Button btnAnswer4;
private Questions[] gameQuestions;
private Questions[] animeQuestions;
private Questions[] techQuestions;
private Questions[] movieQuestions;
private Questions[][] gameCategories = new Questions[4][];
int correctAnswer = -1;
private TransparentProgressDialog progressBar;
private Handler handler;
private Runnable runnable;
Callback cb = new Callback<MyApiData>(){
@Override
public void success(MyApiData myApiData, Response response) {
gameCategories[0] = new Questions[myApiData.getCategory()[0].getQuestions(0).length];
gameCategories[1] = new Questions[myApiData.getCategory()[1].getQuestions(1).length];
gameCategories[2] = new Questions[myApiData.getCategory()[2].getQuestions(2).length];
gameCategories[3] = new Questions[myApiData.getCategory()[3].getQuestions(3).length];
//gameCategories = new Questions[][] {gameQuestions, animeQuestions, techQuestions, movieQuestions};
for(int i = 0; i < 4 ; i++){
for(int j = 0; j < gameCategories[i].length ; j++){
gameCategories[i][j] = myApiData.getCategory()[i].getQuestions(i)[j];
//Log.d("GameFragment", "gameCategories[i][j] - gameCategories["+i+"]["+j+"]: " + gameCategories[i][j].getQuestion());
}
}
//displayQuestion();
progressBar.dismiss();
displayQuestion();
}
@Override
public void failure(RetrofitError error) {
Log.d("GameScreen", "Callback failed!");
}
};
public GameFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_game, container, false);
txtQuestion = (TextView) view.findViewById(R.id.txtQuestion);
btnAnswer1 = (Button) view.findViewById(R.id.btnAnswer1);
btnAnswer2 = (Button) view.findViewById(R.id.btnAnswer2);
btnAnswer3 = (Button) view.findViewById(R.id.btnAnswer3);
btnAnswer4 = (Button) view.findViewById(R.id.btnAnswer4);
btnAnswer1.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) { checkAnswer(view); } });
btnAnswer2.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) { checkAnswer(view); } });
btnAnswer3.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) { checkAnswer(view); } });
btnAnswer4.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
checkAnswer(view);
}
});
handler = new Handler();
progressBar = new TransparentProgressDialog(getActivity(), R.drawable.loading_spinner);
runnable = new Runnable() {
@Override
public void run() {
if (progressBar.isShowing()) {
progressBar.dismiss();
}
}
};
//launchRingDialog();
//RestClient.get().getQuestions(cb);
// Inflate the layout for this fragment
return view;
}
public void launchRingDialog() {
new Thread(new Runnable() {
public void run(){
try {
Log.d("Thred", "Try");
progressBar.show();
RestClient.get().getQuestions(cb);
//Thread.sleep(10000);
} catch (Exception e) {
}
//progressBar.dismiss();
}
}).start();
}
public void checkAnswer(View v){
switch(v.getId()){
case R.id.btnAnswer1:
if(correctAnswer == 1){
feedback(true, btnAnswer1);
}else {
feedback(false, btnAnswer1);
}
break;
case R.id.btnAnswer2:
if(correctAnswer == 2){
feedback(true, btnAnswer2);
}else {
feedback(false, btnAnswer2);
}
break;
case R.id.btnAnswer3:
if(correctAnswer == 3){
feedback(true, btnAnswer3);
}else {
feedback(false, btnAnswer3);
}
break;
case R.id.btnAnswer4:
if(correctAnswer == 4){
feedback(true, btnAnswer4);
}else {
feedback(false, btnAnswer4);
}
break;
default: txtQuestion.setText("Error");
break;
}
}
public void feedback(Boolean correct, Button btn){
if(correct){
btn.setBackgroundColor(Color.GREEN);
btn.setText("CORRECT!");
}else{
btn.setBackgroundColor(Color.RED);
btn.setText("WRONG!");
}
}
@Override
public void onResume() {
super.onResume();
//displayQuestion();
}
public void displayQuestion(){
Random randomizer = new Random();
int randomQuestion;
int category = GTMain.choosenCategory;
if(category == 5){
category = randomizer.nextInt(4);
}
randomQuestion = randomizer.nextInt(25);
Log.d("displayQuestion", "Before if statements");
if(gameCategories != null && gameCategories.length != 0) {
Log.d("displayQuestion", "First if");
if(gameCategories[category] != null && gameCategories[category].length != 0){
Log.d("displayQuestion", "Second if");
txtQuestion.setText(gameCategories[category][randomQuestion].getQuestion());
correctAnswer = gameCategories[category][randomQuestion].getCorrectAnswer();
Log.d("displayQuestion()", "correctAnswer: " + correctAnswer);
btnAnswer1.setText(gameCategories[category][randomQuestion].getAnswers().getA1());
btnAnswer2.setText(gameCategories[category][randomQuestion].getAnswers().getA2());
btnAnswer3.setText(gameCategories[category][randomQuestion].getAnswers().getA3());
btnAnswer4.setText(gameCategories[category][randomQuestion].getAnswers().getA4());
}
}
}
}
PS：在我的主要活动中，我查看应该加载哪个片段。如果它是包含要显示问题和答案的组件的片段（上面的代码中的那个），我调用以下方法：gameFragment.launchRingDialog();（是的，我创建了一个我的GameFragment实例调用该方法之前的片段！）
答案 0 :(得分：0)
当调用onResume（）时，你的RestClient.get（）。getQuestions（cb）仍然在后台运行，你的调用displayQuestion（），所以当然没有显示任何内容。
你可以将displayQuestion（）放在回调的success（）中吗？
Callback cb = new Callback<MyApiData>(){
@Override
public void success(MyApiData myApiData, Response response) {
....
for(int i = 0; i < 4 ; i++){
for(int j = 0; j < gameCategories[i].length ; j++){
...
}
}
displayQuestion();
}
....
};
我还建议您删除onResume（）方法中的displayQuestion（）。