我尝试过对 ArrayList 使用静态变量，但在 ListFragment 类中，在调试时它的值为 null。
我认为 ListFragment 是在初始化 ArrayList 之前创建的，这就是它为 null 的原因，但不确定。
建议我是否可以使用任何其他方式将膨胀的 ArrayList 从 Fragment 类发送到扩展 ListFragment 的其他 Fragment 类。
提前致谢。
目标（这是线索，需要做什么）
在 Monday_fragment 的 onStart() 方法中，使用 findByView() 方法在页面视图中查找保存条目按钮的标签。使用对按钮的引用将 setOnClickListener() 方法附加到保存按钮。您需要在此方法中保存页面上 EditText 字段中包含的时间和日记条目字符串。
使用 findViewById() 还可以获取对第一个 EditText 字段的引用，并使用它来获取该字段的文本作为字符串并将其保存到字符串中。对下一个 EditText - 日记条目重复此操作。您将需要一个可公开访问的变量来存储日期（星期一..星期五）、日期时间字符串和日记条目字符串的引用。使用这些字段创建一个新类 (diaryLogs) 来保存值和一个构造函数，该构造函数采用 int (0 Mon、1 Tue、2 Wed 等) 和两个用于日期时间和日记条目的字符串来初始化对象的实例。由于同一天会产生多个条目，因此使用 ArrayList 来存储这些值。由于该值将在片段之间共享，因此在 MainActivity 类中将该变量声明为静态。使用 ArrayList 的 .add() 方法将新的 diaryLog 添加到 setOnClickListener() 方法中的 ArrayList 中。对其他日记页面片段重复此操作。
monday_list 片段由一个 ListView 和一个用于返回 Monday_fragment 页面的按钮组成。在 monday_list xml 文件中创建这些对象。创建一个扩展 ListFragment 类的 Monday_list_fragment。在 onCreateView() 方法中 inflate() monday_list 资源。
在 onCreate() 方法中，您需要提供单个字符串数组作为 setListAdapter() 方法中用于填充页面上的 ListView 的列表的源。这些字符串位于 MainActivity 中的静态 ListArray 变量中。但是，它们不是所需的形式，您必须解压 diaryLog 元素才能获取所需的字符串。为此，您必须创建一个足够大的字符串数组来容纳要显示的字符串。由于它由日期/时间字符串和日记条目字符串组成，因此每个 diaryLog 元素都有两个这样的字符串。使用 Iterator 迭代 ListArray。将日期字符串和日记字符串复制到本地字符串中。然后使用这个本地字符串作为setListAdapter()的相关参数，以便ListView显示所需的字符串。
在 MainActivity java 文件中添加单击处理程序，以便单击 Monday 片段页面中的 Save Diary Entries 按钮会导致 Monday_list_fragment 使用 FragmentManager 变得可见。还要在 MainActivity 中添加一个单击处理程序，以便单击“返回星期一日记”按钮返回到 Monday_fragment 页面。
UPDATE
类MainActivity
public class MainActivity extends Activity {
public static int Monday=0;
/*public static int Tuesday=1;
public static int Wednesday=2;
public static int Thursday=3;
public static int Friday=4;
public static String timeEntry;
public static String entryEntered;*/
// public static ArrayList<String> logs;
//public static String[] entry;
//public static String time;
//public static String text;
//public static String totalEntry;
//public static ArrayList<DiaryLogs> diaryLogs;
//public static ArrayList<DiaryLogs> test;
//public static DiaryLogs[] entryLogs;
//public static ArrayAdapter<DiaryLogs> monAdapter;
//public static ArrayList< String > myStringList;
//public static ArrayList<DiaryLogs> entryLogs;
public static ArrayList<String> myStringList;
public static ArrayList<String> getMyStringList() {
return myStringList;
}
public void setMyStringList(ArrayList<String> myStringList) {
this.myStringList = myStringList;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Home_fragment hf = new Home_fragment();
fragmentTransaction.replace(android.R.id.content, hf);
fragmentTransaction.commit();
setContentView(R.layout.activity_main);
}
public void monClick(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Monday_fragment mf = new Monday_fragment();
fragmentTransaction.replace(android.R.id.content, mf);
fragmentTransaction.commit();
}
public void tuesClick(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Tuesday_fragment tf = new Tuesday_fragment();
fragmentTransaction.replace(android.R.id.content, tf);
fragmentTransaction.commit();
}
public void wedClick(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Wednesday_fragment wf = new Wednesday_fragment();
fragmentTransaction.replace(android.R.id.content, wf);
fragmentTransaction.commit();
}
public void thursClick(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Thursday_fragment thf = new Thursday_fragment();
fragmentTransaction.replace(android.R.id.content, thf);
fragmentTransaction.commit();
}
public void friClick(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Friday_fragment ff = new Friday_fragment();
fragmentTransaction.replace(android.R.id.content, ff);
fragmentTransaction.commit();
}
public void next_Home_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Monday_fragment mf = new Monday_fragment();
fragmentTransaction.replace(android.R.id.content, mf);
fragmentTransaction.commit();
}
public void previous_Home_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Friday_fragment ff = new Friday_fragment();
fragmentTransaction.replace(android.R.id.content, ff);
fragmentTransaction.commit();
}
public void next_Mon_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Tuesday_fragment tf = new Tuesday_fragment();
fragmentTransaction.replace(android.R.id.content, tf);
fragmentTransaction.commit();
}
public void previous_Mon_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Friday_fragment ff = new Friday_fragment();
fragmentTransaction.replace(android.R.id.content, ff);
fragmentTransaction.commit();
}
public void next_Tues_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Wednesday_fragment wf = new Wednesday_fragment();
fragmentTransaction.replace(android.R.id.content, wf);
fragmentTransaction.commit();
}
public void previous_Tues_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Monday_fragment mf = new Monday_fragment();
fragmentTransaction.replace(android.R.id.content, mf);
fragmentTransaction.commit();
}
public void next_Wed_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Thursday_fragment thf = new Thursday_fragment();
fragmentTransaction.replace(android.R.id.content, thf);
fragmentTransaction.commit();
}
public void previous_Wed_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Tuesday_fragment tf = new Tuesday_fragment();
fragmentTransaction.replace(android.R.id.content, tf);
fragmentTransaction.commit();
}
public void next_Thurs_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Friday_fragment ff = new Friday_fragment();
fragmentTransaction.replace(android.R.id.content, ff);
fragmentTransaction.commit();
}
public void previous_Thurs_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Wednesday_fragment wf = new Wednesday_fragment();
fragmentTransaction.replace(android.R.id.content, wf);
fragmentTransaction.commit();
}
public void next_Fri_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Monday_fragment ff = new Monday_fragment();
fragmentTransaction.replace(android.R.id.content, ff);
fragmentTransaction.commit();
}
public void previous_Fri_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Thursday_fragment wf = new Thursday_fragment();
fragmentTransaction.replace(android.R.id.content, wf);
fragmentTransaction.commit();
}
public void home_Click(View view) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Home_fragment hf = new Home_fragment();
fragmentTransaction.replace(android.R.id.content, hf);
fragmentTransaction.commit();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {
case R.id.action_profile:
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Profile_fragment pf = new Profile_fragment();
fragmentTransaction.replace(android.R.id.content, pf);
fragmentTransaction.commit();
break;
case R.id.action_saveEntries:
break;
case R.id.action_sendAllEntries:
//call delete dialog
deleteDialog();
break;
}
return false;
}
@Override
public void onBackPressed() {
new AlertDialog.Builder(this).setIcon(R.drawable.ic_launcher)
.setTitle("Save entries to DB first?")
.setNegativeButton("No", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
// if no, close app
MainActivity.this.finish();
}
})
.setPositiveButton(android.R.string.ok, new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
// if ok, save entries to Database
}
})
.create().show();
}
public void deleteDialog() {
new AlertDialog.Builder(this).setIcon(R.drawable.ic_launcher)
.setTitle("Are you sure? This will delete all entries.")
.setNegativeButton(android.R.string.cancel, new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
})
.setPositiveButton(android.R.string.ok, new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
})
.create().show();
}
}
自定义对象类 DiaryLogs
public class DiaryLogs {
//public static ArrayList<DiaryLogs> entryLogs;
String timeEntry, entryEntered;
int day;
// single constructor that takes an integer and two string
public DiaryLogs(int day, String timeEntry, String entryEntered) {
super();
this.day = day;
this.timeEntry = timeEntry;
this.entryEntered = entryEntered;
}
public String getTimeEntry() {
return timeEntry;
}
public void setTimeEntry(String timeEntry) {
this.timeEntry = timeEntry;
}
public String getEntryEntered() {
return entryEntered;
}
public void setEntryEntered(String entryEntered) {
this.entryEntered = entryEntered;
}
public int getDay() {
return day;
}
public void setDay(int day) {
this.day = day;
}
@Override
public String toString() {
// TODO Auto-generated method stub
return this.timeEntry + "\n" + this.entryEntered;
}
}
UPDATE
Monday_fragment 类
public class Monday_fragment extends Fragment {
//public ArrayList<String> myStringList;
Bundle bundle;
ArrayList<DiaryLogs> entryLogs;
EditText timeText;
EditText entryText;
DiaryLogs dl;
String timeEntry;
String entryEntered;
ArrayList<String> myStringList;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.monday_fragment, container, false);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
currentDateTime();
super.onViewCreated(view, savedInstanceState);
}
public void currentDateTime() {
EditText timeText = (EditText) getView().findViewById(
R.id.dateTimeEText);
SimpleDateFormat df = new SimpleDateFormat("d/M/yyyy:H:m");
String dateTime = df.format(Calendar.getInstance().getTime());
timeText.setText(dateTime);
}
/*public ArrayList<String> toStringList(Collection<DiaryLogs> entryLogs) {
ArrayList<String> stringList = new ArrayList<String>();
for (DiaryLogs myobj : entryLogs) {
stringList.add(myobj.toString());
}
return stringList;
}*/
public ArrayList<String> toStringList(Collection<DiaryLogs> entryLogs) {
ArrayList<String> stringList = MainActivity.getMyStringList();
for (DiaryLogs myobj : entryLogs) {
String objctString = myobj.toString();
stringList.add(objctString);
}
((MainActivity)getActivity()).setMyStringList(stringList);
return stringList;
}
@Override
public void onStart() {
entryLogs = new ArrayList<DiaryLogs>();
timeText = (EditText) getView().findViewById(R.id.dateTimeEText);
entryText = (EditText) getView().findViewById(R.id.diaryEntryEText);
Button saveBtn = (Button) getView()
.findViewById(R.id.saveDiaryEntryBtn);
saveBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
timeEntry = timeText.getText().toString();
entryEntered = entryText.getText().toString();
dl = new DiaryLogs(1, timeEntry, entryEntered);
entryLogs.add(dl);
//convert entryLogs to string array list
//myStringList = toStringList(entryLogs);
myStringList= MainActivity.getMyStringList();
myStringList = toStringList(entryLogs);
//myStringList.addAll(toStringList(entryLogs));
Toast.makeText(getActivity(), "Entry added \n" + dl,
Toast.LENGTH_SHORT).show();
entryText.setText("");
}
}
);
System.out.println(entryLogs);
Button showBtn = (Button) getView().findViewById(
R.id.showDiaryEntriesBtn);
showBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (myStringList != null) {
bundle = new Bundle();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Monday_list_fragment mlf = new Monday_list_fragment();
bundle.putStringArrayList("list", myStringList);
mlf.setArguments(bundle);
fragmentTransaction.replace(android.R.id.content, mlf);
fragmentTransaction.commit();
}
if (myStringList == null) {
Toast.makeText(getActivity(),
"No entry have been added yet", Toast.LENGTH_SHORT)
.show();
}
}
});
super.onStart();
}
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
}
}
类 Monday_list_fragment
public class Monday_list_fragment extends ListFragment {
ArrayList<String> test;
Bundle bundle;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
bundle = getArguments();
System.out.println(bundle);
//test = bundle.getStringArrayList("list");
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
return inflater
.inflate(R.layout.monday_list_fragment, container, false);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
/* ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, test);
// once adapter set throws runtime error
setListAdapter(adapter);*/
}
}
