所以在我的MainAcivity中编辑一个方法后，我得到一个RuntimeException。
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.tim.timapp
/com.example.tim.timapp.MainActivity}: java.lang.IllegalStateException:
Activity has been destroyed
老实说，我不知道这是从哪里来的。在线搜索表明它对于ChildFragmentManager很重要，但是没有给我一个适合我的修复。
知道我可以做些什么来解决这个异常吗？
PS。如果您需要更多代码或信息，请告诉我们。我的想法因为这个错误而非常慌张，所以我可能会忽略这里的一些东西。
完整日志：
03-30 21:19:47.910 24785-24785/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.tim.timapp, PID: 24785
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.tim.timapp/com.example.tim.timapp.MainActivity}: java.lang.IllegalStateException: Activity has been destroyed
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalStateException: Activity has been destroyed
at android.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1433)
at android.app.BackStackRecord.commitInternal(BackStackRecord.java:687)
at android.app.BackStackRecord.commit(BackStackRecord.java:663)
at com.example.tim.timapp.MainActivity.DrawVariableFragments(MainActivity.java:271)
at com.example.fragments.Settings.GeneralSettingsFragment.onCreateView(GeneralSettingsFragment.java:57)
at android.app.Fragment.performCreateView(Fragment.java:2220)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:973)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1148)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1130)
at android.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1953)
at android.app.FragmentController.dispatchActivityCreated(FragmentController.java:152)
at android.app.Activity.performCreateCommon(Activity.java:6232)
at android.app.Activity.performCreate(Activity.java:6239)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
MainActivity （对不起，这是一个WIP）：
对此抱歉，但我对整个文件超过了30.000个字符的限制 http://pastebin.com/XZ9k995G
DBHandler （早些时候给我悲伤，所以可能与它有关）：
package com.example.tim.timapp;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.DatabaseUtils;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.util.Log;
import java.util.ArrayList;
public class DBHandler extends SQLiteOpenHelper {
private static String tag = "TEST DBHandler";
private static DBHandler sInstance;
// Database Stuff
private static final int DATABASE_VERSION = 6;
private static final String DATABASE_NAME = "LinkDatabase.db";
// Table Stuff
private static final String TABLE_LinkTable = "LinkTable";
private static final String TABLE_SettingsTable = "SettingsTable";
// LinkTable Stuff
private static final String LT_COLUMN_ID = "_id";
private static final String LT_COLUMN_NAME = "name";
private static final String LT_COLUMN_TAG = "tag";
// SettingsTable Stuff
private static final String ST_COLUMN_ID = "_id";
private static final String ST_COLUMN_NAME = "name";
private static final String ST_COLUMN_IP = "ip";
private static final String ST_COLUMN_PORT = "port";
private static final String ST_COLUMN_USERNAME = "username";
private static final String ST_COLUMN_PASS = "pass";
// Table Create Statements
// LinkTable Create Statement
private static final String CREATE_TABLE_LINKS =
"CREATE TABLE " + TABLE_LinkTable + "(" +
LT_COLUMN_ID + " INTEGER PRIMARY KEY, " +
LT_COLUMN_NAME + " TEXT, " +
LT_COLUMN_TAG + " TEXT" + ");";
// SettingsTable Create Statement
private static final String CREATE_TABLE_SETTINGS =
"CREATE TABLE " + TABLE_SettingsTable + "(" +
ST_COLUMN_ID + " INTEGER PRIMARY KEY, " +
ST_COLUMN_NAME + " TEXT, " +
ST_COLUMN_IP + " TEXT, " +
ST_COLUMN_PORT + " TEXT, " +
ST_COLUMN_USERNAME + " TEXT, " +
ST_COLUMN_PASS + " TEXT" + ");";
// TODO: 28-Mar-16 DON"T FORGET TO UPDATE
// Don't forget to update this when adding a new table.
private static final ArrayList<String> createTablesArray = new ArrayList<String>() {{add(CREATE_TABLE_LINKS); add(CREATE_TABLE_SETTINGS);}};
private static final ArrayList<String> tableNamesArray = new ArrayList<String>() {{add(TABLE_LinkTable); add(TABLE_SettingsTable);}};
public ArrayList<String> tagArray;
public static synchronized DBHandler getInstance(Context context) {
if (sInstance == null) {
Log.d(tag, "sInstance == null");
sInstance = new DBHandler(context.getApplicationContext());
}
return sInstance;
}
private DBHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
for (String s : createTablesArray) {
db.execSQL(s);
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
for (String s : tableNamesArray) {
db.execSQL("DROP TABLE IF EXISTS " + s);
}
onCreate(db);
}
public ArrayList<String> returnArray(String base, String column) {
SQLiteDatabase db;
db = getWritableDatabase();
String TABLENAME;
if (base.equalsIgnoreCase("StuffManager")) {
TABLENAME = TABLE_LinkTable;
} else if (base.equalsIgnoreCase("GeneralSettings")) {
TABLENAME = TABLE_SettingsTable;
} else {
Log.e(tag, "String Base not recognised");
return null;
}
String query = "SELECT * FROM " + TABLENAME + " WHERE 1";
Cursor c = db.rawQuery(query, null);
c.moveToFirst();
ArrayList<String> tempArray = new ArrayList<>();
int i = 0;
while(!c.isAfterLast()){
if(c.getString(c.getColumnIndex(column)) != null){
tempArray.add(i, c.getString(c.getColumnIndex(column)));
} else {
Log.e(tag, "String Column not recognised");
return null;
}
c.moveToNext();
i++;
}
c.close();
if (db != null && db.isOpen()) {
db.close();
}
return tempArray;
}
// *** --------- ***
//
// All methods for the SETTINGS_TABLES
//
// *** --------- ***
public void addSettings(String name, String ip, String port, String username, String pass) {
ContentValues values = new ContentValues();
values.put(ST_COLUMN_NAME, name);
values.put(ST_COLUMN_IP, ip);
values.put(ST_COLUMN_PORT, port);
values.put(ST_COLUMN_USERNAME, username);
values.put(ST_COLUMN_PASS, pass);
SQLiteDatabase db;
db = getWritableDatabase();
db.insert(TABLE_SettingsTable, null, values);
db.close();
}
public void updateSettings(int id, String name, String ip, String port, String username, String pass) {
ContentValues values = new ContentValues();
values.put(ST_COLUMN_NAME, name);
values.put(ST_COLUMN_IP, ip);
values.put(ST_COLUMN_PORT, port);
values.put(ST_COLUMN_USERNAME, username);
values.put(ST_COLUMN_PASS, pass);
SQLiteDatabase db;
db = getWritableDatabase();
db.update(TABLE_SettingsTable, values, "_id=" + id, null);
db.close();
}
public void deleteSettings(String name) {
SQLiteDatabase db;
db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_SettingsTable + " WHERE " + ST_COLUMN_NAME + "=\"" + name + "\";");
db.close();
}
public void deleteAllSettings() {
SQLiteDatabase db;
db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_SettingsTable + " WHERE 1");
db.close();
}
public float settingsTableSize() {
SQLiteDatabase db;
db = getReadableDatabase();
float amount = DatabaseUtils.queryNumEntries(db, TABLE_SettingsTable);
db.close();
return amount;
}
public ArrayList<String> settingsNameArrayMethod() {
SQLiteDatabase db;
db = getWritableDatabase();
String query = "SELECT * FROM " + TABLE_SettingsTable + " WHERE 1";
Cursor c = db.rawQuery(query, null);
c.moveToFirst();
int i = 0;
ArrayList<String> nameArray = new ArrayList<>();
while (!c.isAfterLast()) {
if (c.getString(c.getColumnIndex("name")) != null) {
nameArray.add(i, c.getString(c.getColumnIndex("name")));
}
c.moveToNext();
i++;
}
c.close();
db.close();
return nameArray;
}
// *** --------- ***
//
// All methods for the LINK_TABLES
//
// *** --------- ***
public void addStuffLink(String name, String tag) {
ContentValues values = new ContentValues();
values.put(LT_COLUMN_NAME, name);
values.put(LT_COLUMN_TAG, tag);
SQLiteDatabase db;
db = getWritableDatabase();
db.insert(TABLE_LinkTable, null, values);
db.close();
}
public Bundle updateStuffLink(int id, String name, String tag) {
ContentValues values = new ContentValues();
values.put(LT_COLUMN_NAME, name);
values.put(LT_COLUMN_TAG, tag);
SQLiteDatabase db;
db = getWritableDatabase();
db.update(TABLE_LinkTable, values, "_id=" + id, null);
db.close();
ArrayList<String> nameArray = stuffLinksNameArrayMethod();
ArrayList<String> tagArray = tagArrayMethod();
Bundle bundle = new Bundle();
bundle.putStringArrayList("nameArray", nameArray);
bundle.putStringArrayList("tagArray", tagArray);
return bundle;
}
public void deleteStuffLink(String name) {
SQLiteDatabase db;
db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_LinkTable + " WHERE " + LT_COLUMN_NAME + "=\"" + name + "\";");
db.close();
}
public void deleteAllStuffLinks() {
SQLiteDatabase db;
db = getWritableDatabase();
db.execSQL("DELETE FROM " + TABLE_LinkTable + " WHERE 1");
db.close();
}
public ArrayList<String> stuffLinksNameArrayMethod(){
SQLiteDatabase db;
db = getWritableDatabase();
String query = "SELECT * FROM " + TABLE_LinkTable + " WHERE 1";
Cursor c = db.rawQuery(query, null);
c.moveToFirst();
int i = 0;
ArrayList<String> nameArray = new ArrayList<>();
tagArray = new ArrayList<>();
while(!c.isAfterLast()){
if(c.getString(c.getColumnIndex("name")) != null){
nameArray.add(i, c.getString(c.getColumnIndex("name")));
tagArray.add(i, c.getString(c.getColumnIndex("tag")));
}
c.moveToNext();
i++;
}
c.close();
db.close();
return nameArray;
}
public ArrayList<String> tagArrayMethod() {
stuffLinksNameArrayMethod();
return tagArray;
}
public float stuffTableSize(){
SQLiteDatabase db;
db = getReadableDatabase();
float amount = DatabaseUtils.queryNumEntries(db, TABLE_LinkTable);
db.close();
return amount;
}
}
GeneralSettingsFragment
package com.example.fragments.Settings;
import android.app.AlertDialog;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import com.example.fragments.MainFragments.DialogFragments.GeneralSettingsInitialInputDialog;
import com.example.fragments.MainFragments.VariableFragments.GeneralSettingsEmptyFragment;
import com.example.fragments.MainFragments.VariableFragments.GeneralSettingsVariableFragment;
import com.example.fragments.MainFragments.VariableFragments.StuffManagerVariableFragment;
import com.example.tim.timapp.DBHandler;
import com.example.tim.timapp.MainActivity;
import com.example.tim.timapp.R;
import java.util.ArrayList;
public class GeneralSettingsFragment extends Fragment {
DBHandler dbHandler;
MainActivity ma = new MainActivity();
private static Menu optionsMenu;
public static boolean hideDeleteAllButton = false;
LinearLayout linearLayout;
View rootView;
@Override
public void onCreate(Bundle savedInstanceState) {
setHasOptionsMenu(true);
super.onCreate(savedInstanceState);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_generalsettings, container, false);
linearLayout = (LinearLayout) rootView.findViewById(R.id.FragmentContainerGeneralSettings);
if (linearLayout == null) {
Log.e("GMF", "Layout is null");
} else if (linearLayout.getChildCount() == 0) {
GeneralSettingsInitialInputDialog GSIID = new GeneralSettingsInitialInputDialog();
GSIID.show(getFragmentManager(), "dialog");
hideDeleteAllButton = true;
} else {
hideDeleteAllButton = false;
}
ma.DrawVariableFragments("GeneralSettings", "draw");
return rootView;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.stuffmanager_actionbuttons, menu);
optionsMenu = menu;
}
@Override
public void onPrepareOptionsMenu(Menu menu) {
optionsMenu.findItem(R.id.removeAllButton).setVisible(!hideDeleteAllButton);
super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.addButton:
GeneralSettingsInitialInputDialog GSIID = new GeneralSettingsInitialInputDialog();
GSIID.show(getFragmentManager(), "dialog");
return true;
case R.id.removeAllButton:
dbHandler = DBHandler.getInstance(getActivity());
final ArrayList<String> nameArray = dbHandler.settingsNameArrayMethod();
final FragmentManager fm = getFragmentManager();
AlertDialog.Builder removeAllDialog = new AlertDialog.Builder(getActivity())
.setTitle("Delete all?")
.setMessage("Are you sure you want to delete all your devices? This is irreversible.")
.setIcon(R.drawable.ic_delete_black)
.setPositiveButton("Delete", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dbHandler.deleteAllSettings();
for (String name : nameArray){
fm.beginTransaction().remove(fm.findFragmentByTag(name)).commit();
}
fm.executePendingTransactions();
// TODO: 30-Mar-16 Add "No devices created" screen like stuffmanager
hideDeleteAllButton = true;
getActivity().invalidateOptionsMenu();
}
})
.setNegativeButton("Cancel", null);
removeAllDialog.show();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
答案 0 :(得分：3)
MainActivity ma = new MainActivity();
这在Android中无效。您无法创建此类活动的实例，因为它实际上并未附加到Android进程。 MainActivity的此实例不会逐步执行任何生命周期方法，这就是您查看活动已停止的错误的原因。它从未真正开始。
相反，请删除对MainActivity的引用，因为在您的片段中保留这样的引用是不好的做法。每当您需要片段内的MainActivity实例时，请使用以下示例：
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// ...
MainActivity ma = (MainActivity) getActivity();
ma.DrawVariableFragments("GeneralSettings", "draw");
// ...
}