onBackpressed（）在marshmallow版本中无法正常工作
目前我正在使用
Android工作室2.1
编译sdk marshmallow 6.0
构建工具版本23.0.3
在我的项目中，当我使用onBackpressed（）从AppCompatActivity返回Fragment时，我使用了导航抽屉，它在棒棒糖版本上正常工作但在marshmallow版本中无法正常工作。
这是 Fragment_Subjects 类，你可以看到我想进入下一个屏幕的ActionbarSearchSubjects Activity类
这是活动 ActionbarSearchSubjects
现在，当我点击 ActionbarSearchSubjects 操作栏中的“返回”按钮时，它将转到MainActivity而不是 FragmentSubject 此问题仅发生在marshmallow而不是其他Android操作系统中。
FragmentSubject
public class Fragment_Subjects extends Fragment implements SwipeRefreshLayout.OnRefreshListener {
// Connection detector
ConnectionDetector cd;
// Alert dialog manager
AlertDialogManager alert = new AlertDialogManager();
ListView userList;
public static ZipListCustomAdapter userAdapter = null;
public static ArrayList<PDF> SubjectArray = new ArrayList<PDF>();
TextView tv_empty;
View rootView;
private SwipeRefreshLayout swipeRefreshLayout;
// URL to get contacts JSON
private static String url;
public Fragment_Subjects() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
//checking internet connections
private void CheckInternetConnections() {
cd = new ConnectionDetector(getActivity());
// Check for internet connection
if (!cd.isConnectingToInternet()) {
// Internet Connection is not present
alert.showAlertDialog(getActivity(), "Internet Connection Error",
"Please connect to working Internet connection", false);
}
}
@Override
public void onResume() {
super.onResume();
CheckInternetConnections();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_subject, container, false);
cd = new ConnectionDetector(getActivity());
LoadUIelements();
LOAdLisners();
// Inflate the layout for this fragment
return rootView;
}
private void LOAdLisners() {
// set item into adapter
userAdapter = new ZipListCustomAdapter(getActivity(), R.layout.row_item,
SubjectArray);
userList.setAdapter(userAdapter);
swipeRefreshLayout.setOnRefreshListener(this);
/**
* Showing Swipe Refresh animation on activity create
* As animation won't start on onCreate, post runnable is used
*/
swipeRefreshLayout.post(new Runnable() {
@Override
public void run() {
swipeRefreshLayout.setRefreshing(true);
Log.d("Runnable method ", "");
new GetPapers().execute();
}
}
);
/**
* get on item click listener
*/
userList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View v,
final int position, long id) {
TextView tv_paper_name = (TextView) v.findViewById(R.id.tv_paper_name);
String subject_name = tv_paper_name.getText().toString();
File extStore = Environment.getExternalStorageDirectory();
File myFile = new File(extStore.getAbsolutePath() + "/Exam Papers/" + subject_name + ".pdf");
if (myFile.exists()) {
File pdfFile = new File(Environment.getExternalStorageDirectory() + "/Exam Papers/" + subject_name + ".pdf"); // -> filename
Uri path = Uri.fromFile(pdfFile);
Intent pdfIntent = new Intent(Intent.ACTION_VIEW);
pdfIntent.setDataAndType(path, "application/pdf");
pdfIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
try {
startActivity(pdfIntent);
} catch (ActivityNotFoundException e) {
Toast.makeText(getActivity(), "No Application available to view PDF", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(getActivity(), "Download file first", Toast.LENGTH_SHORT).show();
}
}
});
}
private void LoadUIelements() {
swipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swipe_refresh_layout);
userList = (ListView) rootView.findViewById(R.id.listView);
tv_empty = (TextView) rootView.findViewById(R.id.tv_empty);
}
/**
* This method is called when swipe refresh is pulled down
*/
@Override
public void onRefresh() {
Log.d("onRefresh()", "");
new GetPapers().execute();
}
//For fetch the all pdf file in one Directory
List<String> textFiles(String directory) {
List<String> textFiles = new ArrayList<String>();
File dir = new File(directory);
for (File file : dir.listFiles()) {
if (file.getName().endsWith((".pdf"))) {
textFiles.add(file.getName());
}
}
return textFiles;
}
/**
* Async task class to get json by making HTTP call
*/
private class GetPapers extends AsyncTask<Void, Void, Void> {
String Response;
@Override
protected void onPreExecute() {
super.onPreExecute();
// showing refresh animation before making http call
swipeRefreshLayout.setRefreshing(true);
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
JSONParser sh = new JSONParser();
url = "http://gcm_chat/subjectzip.php";
// Making a request to url and getting response
Response = sh.makeServiceCall(url);
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (Response != null) {
SubjectArray.clear();
try {
JSONObject objresponse = new JSONObject(Response);
JSONArray jarray = objresponse.getJSONArray("Data");
for (int i = 0; i < jarray.length(); i++) {
JSONObject jsonObject = jarray.getJSONObject(i);
String subject_name = jsonObject.getString("subject_name");
String subjectPath = jsonObject.getString("subject_upload");
/**
* add item in arraylist
*/
SubjectArray.add(new PDF(subject_name, subjectPath));
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
// userAdapter.notifyDataSetChanged();
// stopping swipe refresh
if (getActivity() != null) {
userAdapter = new ZipListCustomAdapter(getActivity(), R.layout.row_item,
SubjectArray);
userList.setAdapter(userAdapter);
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
}
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_search) {
if (!cd.isConnectingToInternet()) {
// Internet Connection is not present
alert.showAlertDialog(getActivity(), "Internet Connection Error",
"Please connect to working Internet connection", false);
// stop executing code by return
// return;
} else {
Intent i = new Intent(getActivity(), ActionbarSearchSubjects.class);
startActivity(i);
}
return true;
}
return super.onOptionsItemSelected(item);
}
}
ActionbarSearchSubjects
public class ActionbarSearchSubjects extends Activity {
//object of DownloadTask
static DownloadTask downloadTask;
//custom row for list view
static View row;
//image button for actionbar back activity
private ImageButton img_bt;
//edit text for
private EditText et;
//list view for populating subject list
private ListView SubjectLIst;
// String array for static list from fragment_Subjects
private String[] Subject_names = new String[Fragment_Subjects.SubjectArray.size()];
//array list
private ArrayList<String> array_sort;
// text length
int textlength = 0;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.actionbar_search_subjects);
// load all elements and widgets
LOaduiElements();
//load all listners
LoAdUIlisners();
}
// loading elements
private void LoAdUIlisners() {
array_sort = new ArrayList<String>(Arrays.asList(Subject_names));
// setListAdapter(new bsAdapter(this));
SubjectLIst.setAdapter(new bsAdapter(this));
//action bar back button and back activity
img_bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onBackPressed();
}
});
//text watcher for action bar search
et.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {
// Abstract Method of TextWatcher Interface.
}
public void beforeTextChanged(CharSequence s,
int start, int count, int after) {
// Abstract Method of TextWatcher Interface.
}
public void onTextChanged(CharSequence s,
int start, int before, int count) {
//getting text length
textlength = et.getText().length();
//clear array list
array_sort.clear();
//for loop for cnverting text into lower case and adding into array list of array_sort
for (int i = 0; i < Subject_names.length; i++) {
if (textlength <= Subject_names[i].length()) {
if (Subject_names[i].toLowerCase().contains(
et.getText().toString().toLowerCase().trim())) {
array_sort.add(Subject_names[i]);
}
}
}
//called Appendlist method wit parameter of array list
AppendList(array_sort);
}
});
//list view listener for subject list
SubjectLIst.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0,
View arg1, int position, long arg3) {
TextView tv_paper_name = (TextView) findViewById(R.id.tv_paper_name);
String subject_name = tv_paper_name.getText().toString();
File extStore = Environment.getExternalStorageDirectory();
File myFile = new File(extStore.getAbsolutePath() + "/Exam Papers/" + subject_name + ".pdf");
//checking file already present or not?
if (myFile.exists()) {
// pdf file path physical
File pdfFile = new File(Environment.getExternalStorageDirectory() + "/Exam Papers/" + subject_name + ".pdf"); // -> filename
Uri path = Uri.fromFile(pdfFile);
Intent pdfIntent = new Intent(Intent.ACTION_VIEW);
pdfIntent.setDataAndType(path, "application/pdf");
pdfIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
try {
startActivity(pdfIntent);
} catch (ActivityNotFoundException e) {
Toast.makeText(getApplicationContext(), "No Application available to view PDF", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(getApplicationContext(), "Download file first", Toast.LENGTH_SHORT).show();
}
}
});
}
//loading elements
private void LOaduiElements() {
img_bt = (ImageButton) findViewById(R.id.img_bt);
et = (EditText) findViewById(R.id.EditText01);
SubjectLIst = (ListView) findViewById(android.R.id.list);
//for loop for to converting array list to String array
for (int i = 0; i < Fragment_Subjects.SubjectArray.size(); i++) {
try {
Subject_names[i] = Fragment_Subjects.SubjectArray.get(i).getName();
} catch (Exception e) {
e.printStackTrace();
}
}
}
//setting uo base adapter
public void AppendList(ArrayList<String> str) {
SubjectLIst.setAdapter(new bsAdapter(this));
}
public class bsAdapter extends BaseAdapter {
Activity cntx;
public bsAdapter(Activity context) {
// TODO Auto-generated constructor stub
this.cntx = context;
}
public int getCount() {
// TODO Auto-generated method stub
return array_sort.size();
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return array_sort.get(position);
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return array_sort.size();
}
public View getView(final int position, View convertView, ViewGroup parent) {
//setting up custom row for listview
row = convertView;
UserHolder holder = null;
if (row == null) {
LayoutInflater inflater = cntx.getLayoutInflater();
row = inflater.inflate(R.layout.row_item, parent, false);
holder = new UserHolder();
holder.tv_paper_name = (TextView) row.findViewById(R.id.tv_paper_name);
holder.bt_download = (Button) row.findViewById(R.id.bt_download);
row.setTag(holder);
} else {
holder = (UserHolder) row.getTag();
}
// getting subjects names
final PDF user = Fragment_Subjects.SubjectArray.get(position);
holder.tv_paper_name.setText(user.getName());
holder.tv_paper_name.setText(array_sort.get(position));
final UserHolder finalHolder = holder;
holder.bt_download.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.i("Download Button Clicked", "**********");
// Toast.makeText(context, "Download "+ finalHolder.tv_paper_name.getText().toString()+" " + position,
// Toast.LENGTH_LONG).show();
File extStore = Environment.getExternalStorageDirectory();
File myFile = new File(extStore.getAbsolutePath() + "/Exam Papers/" + finalHolder.tv_paper_name.getText().toString() + ".pdf");
//checking file already present or not?
if (!myFile.exists()) {
// execute this when the downloader must be fired
downloadTask = new DownloadTask(cntx);
/* downloadTask.execute("http://upload/uploads/five-point-someone-chetan-bhagat_ebook.pdf",""+finalHolder.tv_paper_name.getText().toString()+".pdf");*/
downloadTask.execute(user.getSubjectPath(), "" + finalHolder.tv_paper_name.getText().toString() + ".pdf");
} else {
Toast.makeText(getApplicationContext(), "File already Exists in " + myFile, Toast.LENGTH_SHORT).show();
}
}
});
return row;
}
}
// holder class for get view method of base adapter
static class UserHolder {
TextView tv_paper_name;
//TextView tv_paper_desc;
Button bt_download;
}
@Override
public void onBackPressed() {
super.onBackPressed();
int count = getFragmentManager().getBackStackEntryCount();
if (count == 0) {
super.onBackPressed();
Intent in = new Intent(getApplicationContext(), MainActivity.class);
startActivity(in);
} else {
getFragmentManager().popBackStack();
}
}
}
MainActivity
public class MainActivity extends AppCompatActivity implements FragmentDrawer.FragmentDrawerListener {
private static String TAG = MainActivity.class.getSimpleName();
public static MainActivity mainActivity;
private Toolbar mToolbar;
private FragmentDrawer drawerFragment;
public Dialog dialog;
public Button Yes, No;
public TextView tv_username;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainActivity = this;
mToolbar = (Toolbar) findViewById(R.id.toolbar);
tv_username = (TextView) findViewById(R.id.tv_username);
tv_username.setText(SharedPreferenceManager.getDefaults("username", getApplicationContext()).toString().toUpperCase());
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayShowHomeEnabled(true);
drawerFragment = (FragmentDrawer)
getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), mToolbar);
drawerFragment.setDrawerListener(this);
displayView(0);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public void onDrawerItemSelected(View view, int position) {
displayView(position);
}
public void displayView(int position) {
Fragment fragment = null;
String title = getString(R.string.app_name);
switch (position) {
case 0:
fragment = new Fragment_Home();
title = getString(R.string.home);
break;
case 1:
fragment = new Fragment_Subjects();
title = getString(R.string.subject);
break;
case 2:
fragment = new Fragment_Download();
title = getString(R.string.download);
break;
case 3:
fragment = new Fragment_Notification();
title = getString(R.string.title_notification);
break;
case 4:
fragment = new Fragment_Chat();
title = getString(R.string.chat);
break;
case 5:
fragment = new Fragment_EditProfile();
title = getString(R.string.editprofile);
break;
case 6:
fragment = new Fragment_Aboutus();
title = getString(R.string.aboutus);
break;
case 7:
title = getString(R.string.action_logout);
dialog = new Dialog(MainActivity.this, R.style.PauseDialog);
dialog.setContentView(R.layout.custom_dialog);
dialog.setTitle("Quit");
TextView text = (TextView) dialog.findViewById(R.id.textDialog);
text.setText("ARE YOU SURE WANT TO LOG OUT?");
dialog.show();
Yes = (Button) dialog.findViewById(R.id.btn_dialog_Yes);
Yes.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
dialog.dismiss();
//for notifiactiion
SharedPreferenceManager.setDefaults_boolean("notification", false, getApplicationContext());
LoginActivity.settings.edit().clear().commit();
SharedPreferenceManager.ClearAllPreferences(getApplicationContext());
Intent intent = new Intent(getApplicationContext(),
LoginActivity.class);
// Here we start the next activity, and then call finish()
// so that our own will stop running and be removed from the
// history stack
// set the new task and clear flags
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();
} catch (Exception e) {
e.printStackTrace();
}
}
});
No = (Button) dialog.findViewById(R.id.btn_dialog_no);
No.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dialog.dismiss();
}
});
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.container_body, fragment);
fragmentTransaction.commit();
// set the toolbar title
// getSupportActionBar().setTitle(title);
getSupportActionBar().setTitle(Html.fromHtml("<font color='#E1E1E1'>" + title + "</font>"));
}
}
@Override
public void onBackPressed() {
int count = getFragmentManager().getBackStackEntryCount();
if (count == 0) {
super.onBackPressed();
Intent in = new Intent(getApplicationContext(), MainActivity.class);
startActivity(in);
} else {
getFragmentManager().popBackStack();
}
}
}
这是我的 gradle 文件
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion '23.0.3'
defaultConfig {
applicationId "info.exampapers.gtu"
minSdkVersion 17
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
testCompile 'junit:junit:4.12'
compile 'com.android.support:support-v4:+'
compile 'com.android.support:design:+'
compile 'com.android.support:appcompat-v7:+'
compile 'com.firebase:firebase-client-android:2.5.0'
compile 'com.firebaseui:firebase-ui:0.3.1'
compile "com.google.android.gms:play-services-gcm:8.4.0"
}
1 个答案:
答案 0 :(得分：0)
我假设您从活动 Fragment_Subjects 开始活动 ActionbarSearchSubjects 。现在来自活动 ActionbarSearchSubjects 您希望返回活动<按下操作栏上的左上方后退按钮，选择strong> Fragment_Subjects 。只需从那里调用this.finish（）或ActivityName.this.finish（）：
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
this.finish();
return true;
}
return super.onOptionsItemSelected(item);
}
如果不存在，请在onCreate中添加以下代码：
getActionBar().setDisplayHomeAsUpEnabled(true);
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