问题
我创建了自定义ListView，其中包含自定义View，以及每个List Item的一些textView。 一切都按预期工作，直到设备方向改变，ListView消失。 我知道当定向更改活动将重新调整时会发生问题。但是，我已经在应用程序中将必要的文件保存为JSON字符串格式，并且当重新创建活动时，我发现数据已加载并成功运行，直到代码结束没有强制关闭，但是listview没有显示？
注意
我确信我的保存数据是可用的，因为这个文件用于防止从互联网上获取数据（如果可用），我已经测试了它，它可以工作！
我的自定义列表视图有listview类提供了arraylist和adapter类，但我不能在这里提供它，因为它太长了。
MAIN CLASS
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.schedule);
aq = new AQuery(this);
lvSchedule = (ListView) findViewById(R.id.listView_schedule);
scheduleLvItems = new ArrayList<Schedule_ListView>();
dm = new DataManager(this);
//check available in app data
String scheduleJSON = dm.readFile("scheduleJSON");
if (scheduleJSON != "empty"){
System.out.println(scheduleJSON);
renderData(scheduleJSON);
}
else{
String url = "http://requestURL/getSchedule_v2.php?+" +
"loginId="+yourID+
"&password="+yourPassword+
"&year=2013&semester=2";
aq.ajax(url,String.class, this,"cb1");
}
}
public void cb1(String url, String html, AjaxStatus status){
System.out.println(html);
renderData(html);
}
public void renderData(String jsonString){
try {
List<List<String>> monData = new ArrayList<List<String>>();
List<List<String>> tueData = new ArrayList<List<String>>();
List<List<String>> wedData = new ArrayList<List<String>>();
List<List<String>> thuData = new ArrayList<List<String>>();
List<List<String>> friData = new ArrayList<List<String>>();
List<List<String>> satData = new ArrayList<List<String>>();
List<List<String>> sunData = new ArrayList<List<String>>();
/*Note [Knowledge]
*JSON Symbol {,} = JSONObject
*JSON symbol [,] = JSONArray
*/
//Change JSONString to JSONArray
JSONArray jsonArray_data = new JSONArray(jsonString);
//Set jsonArray_data in global variable for further use
// ((Global_Variable)getApplicationContext()).setJsonSubject(jsonArray_data);
//Save Persistence Json Array in app data for fetch with out internet
dm.writeFile("scheduleJSON",jsonArray_data.toString());
for(int i = 0; i < jsonArray_data.length(); i++){
//Change object to String and stored each JSON item in Variable
JSONObject dataRecord = jsonArray_data.getJSONObject(i);
String yearSemester = dataRecord.getString("YEAR / SEM");
String courseID = dataRecord.getString("COURSE ID");
String courseName = dataRecord.getString("COURSE NAME");
String courseSection = dataRecord.getString("SECTION");
JSONArray courseInfo = dataRecord.getJSONArray("COURSE INFO");
String finalDate = dataRecord.getString("FINAL DATE");
String finalRoom = dataRecord.getString("FINAL ROOM");
String finalTime = dataRecord.getString("FINAL TIME");
String midtermDate = dataRecord.getString("MIDTERM DATE");
String midtermRoom = dataRecord.getString("MIDTERM ROOM");
String midtermTime = dataRecord.getString("MIDTERM TIME");
int subjectColor = getResources().getColor(SUBJECT_COLOR[i]);
for(int ii = 0; ii < courseInfo.length(); ii++){
//Change object to String and stored each JSON item in Variable
JSONObject infoRecord = courseInfo.getJSONObject(ii);
String day = infoRecord.getString("DAY").replace(".","").trim();
String tStart = infoRecord.getString("TIME").replace(" - ","").trim().substring(0,5);
String tStop = infoRecord.getString("TIME").replace(" - ","").trim().substring(5);
String roomStudy = infoRecord.getString("ROOM STUDY");
String instructor = infoRecord.getString("INSTRUCTOR");
List<String> dataRow = new ArrayList<String>();
if (day.contains("Mon")) {
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
monData.add(dataRow);
} else if (day.contains("Tue")) {
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
tueData.add(dataRow);
} else if (day.contains("Wed")) {
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
wedData.add(dataRow);
} else if (day.contains("Thu")) {
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
thuData.add(dataRow);
} else if (day.contains("Fri")) {
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
friData.add(dataRow);
} else if (day.contains("Sat")) {
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
satData.add(dataRow);
} else if (day.contains("Sun")){
dataRow.add(courseName); //course name
dataRow.add(tStart); //period start
dataRow.add(tStop); //period end
dataRow.add(String.valueOf(subjectColor)); //subject color
dataRow.add(String.valueOf(i)); //subject position in json
sunData.add(dataRow);
}
}
}
if(monData.size() != 0){
scheduleLvItems.add(new Schedule_ListView(
R.drawable.monday_mdpi,
monData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
if(tueData.size() != 0){
scheduleLvItems.add(new Schedule_ListView(
R.drawable.tuesday_mdpi,
tueData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
if(wedData.size() != 0){
scheduleLvItems.add(new Schedule_ListView(
R.drawable.wendesday_mdpi,
wedData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
if(thuData.size() != 0){
scheduleLvItems.add(new Schedule_ListView(
R.drawable.thursday_mdpi,
thuData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
if(friData.size() != 0){
scheduleLvItems.add(new Schedule_ListView(
R.drawable.friday_mdpi,
friData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
if(satData.size() != 0){
scheduleLvItems.add(new Schedule_ListView(
R.drawable.saturday_mdpi,
satData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
if(sunData.size() != 0) {
scheduleLvItems.add(new Schedule_ListView(
R.drawable.sunday_mdpi,
sunData,
getResources().getInteger(R.integer.COLLAPSED_HEIGHT_1)
));
}
//add padding top - bottom for listview
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout header = (LinearLayout) inflater.inflate(R.layout.listview_header, null);
lvSchedule.addFooterView(header, null, false);
lvSchedule.addHeaderView(header, null, false);
//setup listView Adapter
scheduleAdapter = new Schedule_Adapter(Schedule.this, R.layout.schedule_listview, scheduleLvItems);
//setup adapter to listView
lvSchedule.setAdapter(scheduleAdapter);
//setup OnClickListener
lvSchedule.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
int postion = i - lvSchedule.getHeaderViewsCount();
toggle(view, postion);
}
});
}catch (Exception e){
System.out.println(e);
}
}
答案 0 :(得分：1)
这种情况正在发生，因为您将数据分发到onCreate中的ListView，每当您更改方向时，活动将重新启动并且onCreate将不会被调用。因此，它不会被分发。要解决此问题，只需将此行和相关行移至onResume
renderData(scheduleJSON); //take more important lines with it to onResume
应该如下：
protected void onResume()
{
super.onResume();
renderData(scheduleJSON); //take more important lines with it to onResume
}
第二个解决方案：
您可以在方向更改时阻止重新启动活动，方法是将其添加到活动代码
中的清单<activity android:name="YourActivity"
android:screenOrientation="portrait"
android:configChanges="keyboardHidden|orientation"> //this line