我很难为我的应用正确实现“Collection 夹”功能。在对象列表中移动时,用户应该能够选中/取消选中某个 Collection 夹。一旦 Activity 进入onPause();
状态,它就应该保存 Collection 夹列表( boolean 标记的完整列表,以表示是否有某项 Collection 夹... true
表示 Collection 夹,false
表示不是 Collection 夹。)显然,进入onResume();
状态后,应加载列表,以便他们可以查看之前标记的 Collection 夹。
我认为,我的问题确实来自这样一个事实,即初始化后该列表是随机的。我确定我的算法已经关闭,但是我已经尝试了各种方法,以至于我几乎无法再去研究它了。
主要 Activity Java
public class MainActivity extends ActionBarActivity {
Global global_main;
@Override
protected void onCreate(Bundle savedInstanceState) {
global_main = Global.getInstance("all");
}
@Override
protected void onResume(){
super.onResume();
SharedPreferences settings = getSharedPreferences(FILE_FAVORITES, 0);
for(int index = 0; index < TOTAL_QUESTIONS; index++){
boolean favFromFile = settings.getBoolean(("savedFavorite_" + String.valueOf(index)), false);
global_main.setFav(index, favFromFile);
}
}
@Override
protected void onPause(){
super.onPause();
SharedPreferences settings = getSharedPreferences(FILE_FAVORITES, 0);
SharedPreferences.Editor editor = settings.edit();
for(int index = 0; index < TOTAL_QUESTIONS; index++){
editor.putBoolean(("savedFavorite_" + String.valueOf(index)), global_main.getFav(index));
// Commit the edits!
editor.commit();
}
}
练习Java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
selectedSection = intent.getStringExtra(chooseSection.chosenSection);
global = Global.getInstance(selectedSection);
}
全局类
public class Global {
private static Global global = null;
//Current total of questions which the user has chosen
//EX: if Multiplication was chosen and has 10 questions in the array
//Then this equals 10
int CURRENT_TOTAL;
//This is the position that the first question of the user's choice starts with
//EX: If user chooses Multiplication, and the multiplication questions start at questions[19];
//Then this equals 19
int CURRENT_START;
//This is the position that the last question of the user's choice ends with
//EX: If user chooses Multiplication, and the multiplication questions end at questions[24];
//Then this equals 24
int CURRENT_END;
//Basic question structure
class questionStruct
{
String q;
String a;
int position; //original position in the array;
boolean favorite;
}
//Array of question structures
questionStruct[] questions = new questionStruct[TOTAL_QUESTIONS];
//userChoice is the choice of question type that the user has selected.
//EX: Multiplication, Division, Addition, Subtraction, or All/Default
public static Global getInstance(String userChoice) {
if(global == null)
{
global = new Global();
global.initialize();
}
global.getChoice(userChoice);
global.setQuestionsDefault();
global.randomize();
return global;
}
public void initialize() {
for (int i = 0; i < TOTAL_QUESTIONS; i++) {
questions[i] = new questionStruct();
}
questions[0].q = "Question 1 Text";
questions[0].a = "Answer";
questions[0].position = 0;
questions[1].q = "Question 2 Text";
questions[1].a = "Answer";
questions[1].position = 1;
questions[2].q = "Question 3 Text";
questions[2].a = "Answer";
questions[2].position = 2;
....ETC.
....ETC.
....ETC.
}
public void setQuestionsDefault(){
questionStruct temp = new questionStruct();
for(int index = 0; index < TOTAL_QUESTIONS; index++){
int count = questions[index].position;
temp = questions[count];
questions[count] = questions[index];
questions[index] = temp;
temp = null;
}
}
//Randomize the questions only within the range of the category
//which the user has chosen
public void randomize(){
for(int index = CURRENT_END; index >= CURRENT_START; index --)
{
//Generate random number to switch with random block
Random rand = new Random();
int currentQ = rand.nextInt((CURRENT_END - CURRENT_START) + 1) + CURRENT_START;
//Switch two Question blocks
questionStruct temp = questions[currentQ];
questions[currentQ] = questions[index];
questions[index] = temp;
}
}
public void setFav(int q, boolean b){
questions[q].favorite = b;
}
public boolean getFav(int q){
return questions[q].favorite;
}
那可能是与我的问题有关的一切。如果我遗漏了任何内容或没有任何意义,我深表歉意。随意问的问题。我目前仍在修改所有内容以使其正常工作,因此我可能已经复制了一些不太合计的内容。
编辑:我还将添加“Collection 夹”按钮单击的代码,以将 Collection 夹变成非 Collection 夹,反之亦然。即使对完成这项工作至关重要,但它并不是很简单,我也不担心它能否正常运行。但是,如果有人觉得自己想看它,然后反过来帮助我,那就来了。
这也位于“练习问题” Java文件中:
public void setFavoriteButton(){
if(global.getFav(tempQQ)){
FAVORITE.setBackgroundColor(Color.YELLOW);
}
else{
FAVORITE.setBackgroundColor(getResources().getColor(R.color.primary));
}
}
@Override
public void onClick(View v){
switch(v.getId()){
case R.id.favorite:
updateFavorite();
break;
}
}
public void updateFavorite(){
if(global.getFav(tempQQ)){
global.setFav(tempQQ, false);
}
else{
global.setFav(tempQQ, true);
}
setFavoriteButton();
}
编辑:我应该补充一点,我相信这个问题是算法性的。如果我不喜欢将“随机化”功能与 Collection 夹一起使用,我会很好的。但是我认为两者对于我的应用程序非常有用都非常重要。所以这就是我的重点所在,尝试同时实现 Collection 夹功能,同时每次调用Global时都保持随机性。
最佳答案
我真的建议您使用一种更加面向对象的方法来处理模型。
您可以创建模型类Quiz
,它可能看起来像这样:
class Quiz{
private boolean favorite;
private String question;
private String answer;
public Quiz(String question, String answer){
this.question = question;
this.answer = answer;
}
public boolean isFavorite() {
return favorite;
}
public void setFavorite(boolean favorite) {
this.favorite = favorite;
}
//...
}
这样,您可以创建
Quiz
列表,并进行随机播放,排序,检查 Collection 夹等等: //Create the list of questions
ArrayList<Quiz> myQuiz = new ArrayList<Quiz>();
myQuiz.add(new Quiz("Question?", "Ansewer!"));
//...
//Shuffle all!
Collections.shuffle(myQuiz);
//Iterate and check for favorites
for(Quiz q : myQuiz){
if(q.isFavorite()){
//this is favorite!
}
}
关于数据的持久性,您可以考虑使用 SQLite 方法,或者仅在
SharedPreference
中使用serialize your list and save it。关于java - 在随机抽取的问题列表上创建 “favorite”功能,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/29324980/