I'm trying to serlize an Enum Class so I can restore in in onCreate() method so each run I have an updated class.
Here is the code for serlizing and deserializing the class:
private void serializeModulesManager() {
try {
FileOutputStream fos = openFileOutput("modules.ser",
Context.MODE_PRIVATE);
ObjectOutputStream out = new ObjectOutputStream(fos);
out.writeObject(Module.values());
out.close();
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private void restoreModulesManager() {
FileInputStream fileIn;
Module[] arr = null;
try {
fileIn = openFileInput("modules.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
arr = (Module[]) in.readObject();
for (Module c : arr) {
Module.valueOf(c.name()).serilize(c);
}
in.close();
fileIn.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (StreamCorruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I call serializeModulesManager() in onDestroy() , and I call restoreModulesManager() in onCreate()..
The problem is that when I force close (from task manager), ObjectInputStream fails to read the object and I get an "EOFException"..
How can I fix this?
Here is how i would handle this. This is a simple object with only a title field but you can use this same idea for more complicated objects
public class MyObject implements Parcelable{
public String title;
public MyObject(){}
public MyObject(Parcel source){
title = source.readString();
}
public void setTitle(String title){
this.title = title;
}
public String getTitle(){
return this.title;
}
// Parcel Overrides
#Override
public int describeContents(){return 0;}
#Override
public void writeToParcel(Parcel dest, int flags){
dest.writeString(title);
}
// Parcelable Creator
public static final Parcelable.Creator<MyObject> CREATOR = new Parcelable.Creator<MyObject>(){
#Override
public MyObject createFromParcel(Parcel source){
return new MyObject(source);
}
#Override
public MyObject [] newArray(int size){
return new MyObject[size];
}
}
}
And then in your class that instantiates the object
// Add this in onSavedInstanceState(Bundle outState)
outState.putParcelableArray("MyObjectArray",myObjects);
then in OnCreate or whichever method your using to restore UI
// Add this
myObjects = (MyObject [])savedInstanceState.getParcelableArray("MyObjectArray");
Related
I'm able to clear a single package name's data through this snippet. However, i want it to handle more than one package names. in other words, it should clear two more package names' data
private void clearData() {
//"com.uc.browser.en"
//"pm clear com.sec.android.app.sbrowser"
String cmd = "pm clear com.sec.android.app.sbrowser" ;
ProcessBuilder pb = new ProcessBuilder().redirectErrorStream(true)
.command("su");
Process p = null;
try {
p = pb.start();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// We must handle the result stream in another Thread first
StreamReader stdoutReader = new StreamReader(p.getInputStream(),
CHARSET_NAME);
stdoutReader.start();
out = p.getOutputStream();
try {
out.write((cmd + "\n").getBytes(CHARSET_NAME));
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
out.write(("exit" + "\n").getBytes(CHARSET_NAME));
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
out.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
p.waitFor();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String result = stdoutReader.getResult();
}
}
The ProcessCommandsSU class starts an su process in which to run a list of commands, and provides an interface to deliver the output to an Activity asynchronously. Unlike the example you're following, this class will not block the UI thread. The Activity must implement the OnCommandsReturnListener interface.
public class ProcessCommandsSU extends Thread {
public interface OnCommandsReturnListener {
public void onCommandsReturn(String output);
}
private final Activity activity;
private final String[] cmds;
public ProcessCommandsSU(Activity activity, String[] cmds) {
if(!(activity instanceof OnCommandsReturnListener)) {
throw new IllegalArgumentException(
"Activity must implement OnCommandsReturnListener interface");
}
this.activity = activity;
this.cmds = cmds;
}
public void run() {
try {
final Process process = new ProcessBuilder()
.redirectErrorStream(true)
.command("su")
.start();
final OutputStream os = process.getOutputStream();
final CountDownLatch latch = new CountDownLatch(1);
final OutputReader or = new OutputReader(process.getInputStream(), latch);
or.start();
for (int i = 0; i < cmds.length; i++) {
os.write((cmds[i] + "\n").getBytes());
}
os.write(("exit\n").getBytes());
os.flush();
process.waitFor();
latch.await();
process.destroy();
final String output = or.getOutput();
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
((OnCommandsReturnListener) activity).onCommandsReturn(output);
}
}
);
}
catch (IOException | InterruptedException e) {
e.printStackTrace();
}
}
private class OutputReader extends Thread {
private final InputStream is;
private final StringBuilder sb = new StringBuilder();
private final CountDownLatch latch;
public OutputReader(InputStream is, CountDownLatch latch) {
this.is = is;
this.latch = latch;
}
public String getOutput() {
return sb.toString();
}
public void run() {
try {
final BufferedReader reader = new BufferedReader(
new InputStreamReader(is));
String line = "";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
}
catch (IOException e) {
e.printStackTrace();
}
latch.countDown();
}
}
}
Using the class is quite simple. We first ensure that our Activity implements the interface. We then create an instance, passing the Activity and our array of commands in the constructor, and call its start() method. In the following example, it's assumed that the Activity has a TextView named textOutput to display the returned output:
public class MainActivity extends Activity
implements ProcessCommandsSU.OnCommandsReturnListener {
...
#Override
public void onCommandsReturn(String output) {
textOutput.append(output + "\n");
}
private void runCommands() {
final String[] cmds = {
"ping -c 5 www.google.com",
"pm list packages android",
"chdir " + Environment.getExternalStorageDirectory(),
"ls"
};
new ProcessCommandsSU(MainActivity.this, cmds).start();
}
}
My device is not rooted, so this was tested with the commands you see in the code above. Simply replace those commands with your pm clear commands.
I use a bluetooth_access Async task to establish a connection and I need continue to use the input stream and out stream of the bluetooth socket I established.
The issue I having is when I clicked button1 or button2, it sometimes (not all the times) cause Software caused connection abort. It got tripped on out.write(bytes) when clicked.
public class MainActivity extends Activity implements OnClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = (Button)this.findViewById(R.id.button1);
button2 = (Button)this.findViewById(R.id.button2);
button3 = (Button)this.findViewById(R.id.button3);
button1.setEnabled(false);
button2.setEnabled(false);
button3.setEnabled(false);
button1.setOnClickListener(this);
button2.setOnClickListener(this);
button3.setOnClickListener(this);
try {
for (int i = 0; i < 3; i++) {
test();
}
} catch (Exception e) {
e.printStackTrace();
}
}
private boolean connected = false;
private BluetoothSocket sock;
private InputStream in;
private OutputStream out;
private Button button1;
private Button button2;
private Button button3;
private TextView data_t;
private BufferedReader in_read;
public void test() throws Exception {
if (connected) {
return;
}
new bluetooth_access().execute("");
}
#Override
public void onClick(View v){
// TODO Auto-generated method stub
if(v.equals(button1)){
String s = "turn left";
byte[] bytes=s.getBytes();
try {
out.write(bytes);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(v.equals(button2)){
String s = "turn right";
byte[] bytes=s.getBytes();
try {
out.write(bytes);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//new post_data().execute("");
}
if(v.equals(button3)){
String s = "read ADC";
byte[] bytes=s.getBytes();
try {
out.write(bytes);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class bluetooth_access extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
BluetoothDevice Pi = BluetoothAdapter.getDefaultAdapter().
getRemoteDevice("00:15:83:0C:BF:EB");
Method m=null;
try {
m = Pi.getClass().getMethod("createRfcommSocket",
new Class[] { int.class });
} catch (NoSuchMethodException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
sock = (BluetoothSocket)m.invoke(Pi, Integer.valueOf(1));
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
sock.connect();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.d("PiTest", "++++ Connected");
return null;
}
#Override
protected void onPostExecute(String result) {
;
TextView text = (TextView) findViewById(R.id.textView5);
text.setText("Connected through Bluetooth");
button1.setEnabled(true);
button2.setEnabled(true);
button3.setEnabled(true);
// original
try {
in = sock.getInputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
out=sock.getOutputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
}
}
You are trying to write to a socket stream from your main UI thread (from onClick), i would consider doing all socket communication from asynctask itself, or another thread if needed.
your connected variable is not being set, not sure if that was intentional, it can cause multiple execution of your bluetooth asynctask.
I'm currently learning about IO and Async but am having issues. I'm following a guide, and according to the guide this is supposed to work. I have created an activity with a simple EditText, TextView, and 2 Buttons(save and load). I am trying to have the save button take the text in the EditText and save to internal storage, and the load button take whatever is saved and set the TextView as that. Everything works flawlessly when I put all the code to run in the UI thread, but if I change the code to have the UI thread call the Async class for the loading, nothing seems to happen.
**Packages and imports have been removed to save space.
public class InternalData extends Activity implements OnClickListener {
EditText etSharedData;
TextView tvDataResults;
FileOutputStream fos;
String FILENAME = "InternalString";
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.sharedpreferences);
setupVariables();
}
private void setupVariables() {
Button bSave = (Button) findViewById(R.id.bSave);
Button bLoad = (Button) findViewById(R.id.bLoad);
etSharedData = (EditText) findViewById(R.id.etSharedPrefs);
tvDataResults = (TextView) findViewById(R.id.tvLoadSharedPrefs);
bSave.setOnClickListener(this);
bLoad.setOnClickListener(this);
try {
fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.bSave:
String sData = etSharedData.getText().toString();
try {
fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(sData.getBytes());
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
case R.id.bLoad:
String sCollected = null;
FileInputStream fis = null;
try {
fis = openFileInput(FILENAME);
byte[] dataArray = new byte[fis.available()];
while(fis.read(dataArray) != -1){
sCollected = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
try {
fis.close();
tvDataResults.setText(sCollected);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
break;
}
}
The previous code makes everything work, but the UI lags a bit when trying to load large strings. When I try to have an LoadSomeStuff(Async) class do the loading, it does absolutely nothing when I hit Load on my phone. Within the LoadSomeStuff class it has the doInBackground method open the file and read the data into a string then return that string, and the onPostExecute method set the TextView's text to the returned String. Here's the code:
The onClick method for load button has:
new LoadSomeStuff().execute(FILENAME);
LoadSomeStuff Class *Note: This class is declared within the InternalData class.
public class LoadSomeStuff extends AsyncTask<String, Integer, String>{
#Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
String sCollected = null;
FileInputStream fis = null;
try {
fis = openFileInput(FILENAME);
byte[] dataArray = new byte[fis.available()];
while(fis.read(dataArray) != -1){
sCollected = new String(dataArray);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
try {
fis.close();
return sCollected;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return null;
}
protected void onPostExecute(String result){
tvDataResults.setText(result);
}
}
}
Any help is greatly appreciated, thanks!
It actually looks like I had an extra method or two(like onPreExecute) with no code in them and when I deleted them it starting working.
I am using FTP to upload a file. This works great. This file contains information what the app should do.
So I am doing the following:
1) Download the file with Apache FTP Client (seems to work fine)
2) Try to read out the file with a BufferedReader and FileReader.
The problem:
I get a NullPointerException while reading the file. I guess that this is a timing problem.
The code has this structure:
...
getFile().execute();
BufferedReader br = new BufferedReader(...);
How can I solve this problem?
I have to use a seperate Thread (AsyncTask) to download the file because otherwise it will throw a NetworkOnMainThread Exception.
But how can I wait until the file is completely downloaded without freezing the UI?
I cannot use the BufferedReader inside AsyncTask because I use GUI elements and I have to run the interactions on the GUI Thread, but I have no access to it from AsyncTask. RunOnUiThread does not work as well because I am inside a BroadcastReceiver.
Some code:
private class GetTask extends AsyncTask{
public GetTask(){
}
#Override
protected Object doInBackground(Object... arg0) {
FTPClient client = new FTPClient();
try {
client.connect("*****");
}
catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
client.login("*****", "*****");
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileOutputStream fos = null;
try {
fos = new FileOutputStream( "/sdcard/"+userID+".task" );
}
catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
resultOk &= client.retrieveFile( userID+".task", fos );
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
Thread.sleep(5000);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}/**
try {
client.deleteFile(userID+".task");
}
catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
**/
try {
client.disconnect();
}
catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
return null;
}
}
The Broadcastreceiver class:
public class LiveAction extends BroadcastReceiver {
...
private Context cont;
FileReader fr = null;
BufferedReader br;
#Override
public void onReceive(Context context, Intent intent)
{
cont = context;
...
new GetTask().execute();
try {
Thread.sleep(3000);
}
catch (InterruptedException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
fr = new FileReader("/sdcard/"+userID+".task");
}
catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
br = new BufferedReader(fr)
String strline = "";
try {
while ((strline = br.readLine()) != null){
if(strline.equals("taskone")){
//Some GUI Tasks
}
....
This is the relevant code.
I think the best approach would be to read the file's contents from the doInBackground inside the AsyncTask and then output an object which contains the info you need on the onPostExecute method of the async stask and then manipulate your UI.
private AsyncTask<String,Void,FileInfo> getFile(){
return new AsyncTask<String,Void,FileInfo>{
protected FileInfo doInBackground(String url){
FileInfo finfo = new FileInfo(); // FileInfo is a custom object that you need to define that has all the stuff that you need from the file you just downloaded
// Fill the custom file info object with the stuff you need from the file
return finfo;
}
protected void onPostExecute(FileInfo finfo) {
// Manipulate UI with contents of file info
}
};
}
getFile().execute();
Another option is to call another AsyncTask from onPostExecute that does the file parsing but I would not recommend it
I would try some thing like this:
private class GetTask extends AsyncTask{
LiveAction liveAction;
public GetTask(LiveAction liveAction){
this.liveAction = liveAction;
}
...
#Override
protected void onPostExecute(String result) {
liveAction.heyImDoneWithdownloading();
}
}
Ps: why the Thread.sleep(5000)?
public class LiveAction extends BroadcastReceiver {
...
public void heyImDoneWithdownloading(){
//all the things you want to do on the ui thread
}
}
I have two classes/Activities:
FirstClass:
public class FirstClass extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void addData(String filename, String data); {
SecondClass second = new SecondClass();
second.save(name, data);
}
}
SecondClass:
public class SecondClass extends Activity {
public void save(String filename, String data) {
try {
FileOutputStream fos = openFileOutput(filename, Context.MODE_PRIVATE);
fos.write(data.getBytes());
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
As you can see, what I want to do is to call a method from SecondClass in FirstClass. The method savse some data to the internal storage.
What is the correct way of doing this? I know i should probably do something with Context, but i don't know what exactly.
Make it as a simple java class.
public class ThirdClass
{
public void save(String filename, String data, Context context)
{
try {
FileOutputStream fos = context.openFileOutput(filename,Context.MODE_PRIVATE);
fos.write(data.getBytes());
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Call this method like in your First Activity.
ThirdClass third= new ThirdClass();
third.save(name, data,this);
Alternative If you don't want to make the Third class and want to do with SecondClass. Then make this save method to static.
public class SecondClass extends Activity
{
//Oncreate method....
public static void save(String filename, String data)
{
try {
FileOutputStream fos = openFileOutput(filename,Context.MODE_PRIVATE);
fos.write(data.getBytes());
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
and Call this method from First Activity.
SecondClass.save(name, data);
make save a static method and/or move it to its own static class (not activity).
So you can call it using the following:
SecondClass.save(name, data);
and define it as the following:
public static void save(String filename, String data)
{
You should create a class named something like SaveHelper, that doesn't extend activity and add a static method so you can do:
FileHelper.save(...)
public class FileHelper {
public static void save(Context context, String filename, String data) {
try {
FileOutputStream fos = context.openFileOutput(filename, Context.MODE_PRIVATE);
fos.write(data.getBytes());
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}