I'm creating an application which has following functionality.
User selects the sensors which are available in the device.
The UI shows the selected Sensor Name and readings in a Listview.(Values update real time)
I have a custom class to store sensor data (SenseData) and custom view to display sensor name and readings.
I wrote a custom Adaptor class which takes a list of SenseData to populate a list view component in my activity.
What I want to do is, take a list of SenseData.
I'm trying this for about a week and didn't get any solutions.
I'll be very grateful if someone can give me a hint.
EDITED:
Adaptor class
public class SensorAdaptor extends BaseAdapter{
Context context;
List<SenseData> senseData;
public SensorAdaptor(Context context, List<SenseData> senseData){
this.context = context;
this.senseData = senseData;
}
#Override
public int getCount() {
return senseData.size();
}
#Override
public Object getItem(int position) {
return senseData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view;
if(convertView == null){
view = inflater.inflate(R.layout.view_sensor, parent, false);
holder = new ViewHolder();
holder.name = (TextView) view.findViewById(R.id.senseName);
holder.data = (TextView) view.findViewById(R.id.senseReading);
view.setTag(holder);
}else{
view = convertView;
holder = (ViewHolder) view.getTag();
}
SenseData data = senseData.get(position);
holder.name.setText(data.getSensorName());
holder.data.setText(data.getSensorValues());
return null;
}
public class ViewHolder{
TextView name;
TextView data;
}
}
onSensorChanged method
#Override
public void onSensorChanged(SensorEvent event) {
this.event = event;
//SupportedSensors contains the predefined sensor types. sensor is a SenseData type object
Intent filter = new Intent(new
SupportedSensors().getType(event.sensor.getType()));
filter.putExtra("value", event.values[0]);
ctx.sendBroadcast(filter); //ctx is the context
}
Then I receive broadcasts with filters which have sensor names as action. But I couldn't find out a way to return a list in Broadcast receiver. SenseData class has setters and getters to set and get data.
public class SensorBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
switch(intent.getAction()){
case "accelerometer":
System.out.println("Accelerometer");
break;
case "gyroscope":
System.out.println("Gyroscope");
break;
case "gravity":
System.out.println("Gravity");
break;
case "proximity":
System.out.println("Proximity");
break;
case "pressure":
System.out.println("Pressure");
break;
case "light":
System.out.println("Light");
break;
case "magnetometer":
System.out.println("Magnetometer");
break;
case "rotation":
System.out.println("Rotation Vector");
break;
}
}
The receiver is registered in the Activity
IntentFilter filter = new IntentFilter("accelerometer");
SensorBroadcastReceiver receiver = new SensorBroadcastReceiver();
registerReceiver(receiver, filter);
I can add a List<SenseData> sensordatalist to SensorBroadcastReceiver but how to get values real time?
Thank you very much.
I was able to solve my problem by using the following method....
Create a class RealTimeSensorReader which reads the sensors.
public void onSensorChanged(SensorEvent event) {
RealTimeSensor realTimeSensor = new RealTimeSensor();
realTimeSensor.setName(AvailableSensors.getType(event.sensor.getType()).toUpperCase());
realTimeSensor.setValueX(event.values[0]+"");
realTimeSensor.setValueY(event.values[1]+"");
realTimeSensor.setValueZ(event.values[2]+"");
System.out.println(values);
TempStore.sensor.put(AvailableSensors.getType(event.sensor.getType()), realTimeSensor);
Intent intent = new Intent();
intent.setAction("sensor");
context.sendBroadcast(intent);
adaptor.notifyDataSetChanged();}
Define a separate class TempStore which contains two static fields
a ConcurrentHashMap and a LinkedList which are for store sensor
data and to populate the ListView separately.
public class TempStore {
public static ConcurrentMap<String, RealTimeSensor> sensor = new ConcurrentHashMap<>();
public static ArrayList<RealTimeSensor> realTimeSensors = new ArrayList<>();
In onSensorChanged method I put the sensor values with the sensor
name as the key to the HashMap. And send a broadcast whenever a
sensor is changed.
Created a broadcast listener which listen to that broadcast, and
clear the current LinkedList values and add the values set of the
HashMap.
TempStore.realTimeSensors.clear();
TempStore.realTimeSensors.addAll(TempStore.sensor.values());
What I need to know is whether this method is correct or wrong.
Thank you very much
Related
I want to load the clicked image in the next activity in fullscreen view. I don't know what I am doing wrong. The app is running completely fine but the image is not loading on the next screen. am new to android development and I thought I should start learning by doing a project. I am not understanding what is the problem in my coding.
public class CategoriesAdapter extends RecyclerView.Adapter<CategoriesAdapter.ImageViewHolder> {
private Context mCtx;
private List<Category> imageslist;
public CategoriesAdapter(Context mCtx, List<Category> imageslist) {
this.mCtx = mCtx;
this.imageslist = imageslist;
}
#NonNull
#Override
public ImageViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view= LayoutInflater.from(mCtx).inflate(R.layout.recyclerview_images,parent,false);
return new ImageViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull final ImageViewHolder holder, final int position) {
final Category images=imageslist.get(position);
Glide.with(mCtx).load(images.url).into(holder.imageView);
holder.imageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent=new Intent(mCtx, LoadWall.class);
intent.putExtra("url", (Parcelable) imageslist.get(position));
mCtx.startActivity(intent);
}
});
}
#Override
public int getItemCount() {
return imageslist.size();
}
class ImageViewHolder extends RecyclerView.ViewHolder{
ImageView imageView;
public ImageViewHolder(#NonNull View itemView) {
super(itemView);
imageView=itemView.findViewById(R.id.image_view);
}
}
}
This is the activity where I want to load the image. But its not loading. Please Help
public class LoadWall extends AppCompatActivity {
ImageView imageView;
int myImage;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_load_wall);
imageView=findViewById(R.id.load_image);
get();
}
private void get(){
if(getIntent().hasExtra("url")){
String image=getIntent().getStringExtra("url");
set(image);
}
else{
Toast.makeText(this,"No Data",Toast.LENGTH_SHORT).show();
}
}
private void set(String image){
Glide.with(this).load(image).into(imageView);
}
}
Here you only need to pass URL as a String. Parcelable is not required.
intent.putExtra("url", imageslist.get(position).getUrl());
Option 1)
In your next activity you are looking for String.
String image=getIntent().getStringExtra("url");
in first activity in onClick() change your code to this.
Intent intent=new Intent(mCtx, LoadWall.class);
intent.putExtra("url", imageslist.get(position));
intent.startActivity(intent);
As i see imageslist.get(position) will return Category so you will need to add your url parameter. Something like this imageslist.get(position).getUrl();
Option 2)
If you want to get Category object then in next activity change to this
Category category = getIntent().getParcelableExtra("url");
Your imagesList contains data of type Category and you send an entry from this list to the next activity. However, the second activity expects a String to be received. It will check to see if it has an extra (it has - but not what you need), then try to retrieve that value as a String which will result in a null String. Having null, Glide will not load anything.
In other words, you made a small mistake on what data you use. When you load the data, you do it correctly by using the url field
final Category images=imageslist.get(position);
Glide.with(mCtx).load(**images.url**).into(holder.imageView);
But when you are passing it to the next activity, you send the entire object
intent.putExtra("url", **(Parcelable) imageslist.get(position)**);
Using the url field as you did in the first case will make your app work properly.
Start your Activity
Intent intent=new Intent(mCtx, LoadWall.class);
intent.putExtra("url", images.url);
mCtx.startActivity(intent);
I am developing an app which has a text message interface (something like Facebook Messenger, Whatsapp, etc). I want to be able to change the background color of all the chat bubbles (a ListView of TextViews) sent by the user when they pick a new color (in a NavigationView).
However, with the current code that I have, I only am able to change the color after the EditText used to compose the message is clicked again. Or I am able to only edit the first bubble sent, but as soon as the color is changed.
Here's what I tried :
ItemColor1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v){
Toast.makeText(activity, "Couleur mise à jour", Toast.LENGTH_SHORT).show();
currentTheme = position;
SharedPreferences.Editor editor = pref.edit();
editor.putInt("indexColorSelected",currentTheme);
editor.apply();
chatAdapter.notifyDataSetChanged();
//the following changes only the first message sent
for(int i=0; i<chatAdapter.getCount(); i++){
ChatData message = chatMessageList.get(position);
TextView msg = activity.findViewById(R.id.text);
msg.setText(message.body);
msg.setBackgroundResource(R.drawable.user_color1);
}
}
});
ChatData is a custom Class that I created which looks like this :
public class ChatAdapter extends BaseAdapter {
private static LayoutInflater inflater = null;
private ArrayList<ChatData> chatMessageList;
private Context mContext;
ChatAdapter(Activity activity, ArrayList<ChatData> list) {
mContext = activity;
chatMessageList = list;
inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
...
}
Color drawable:
<corners
android:bottomRightRadius="5dp"
android:radius="40dp"/>
<gradient
android:angle="45"
android:endColor="#01f1fa"
android:startColor="#0189ff"
android:type="linear" />
</shape>
getView() method of the Adapter:
public View getView(int position, View convertView, ViewGroup parent) {
ChatData message = chatMessageList.get(position);
View vi = convertView;
if (convertView == null)
vi = inflater.inflate(R.layout.msglist, parent, false);
TextView msg = vi.findViewById(R.id.text);
msg.setText(message.body);
LinearLayout layout = vi.findViewById(R.id.message_layout);
LinearLayout parent_layout = vi.findViewById(R.id.message_layout_parent);
inflater = (LayoutInflater) this.mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// if message is mine then align to right
if (message.isMine) {
layout.setGravity(Gravity.RIGHT);
int couleurBubble = getCouleurSelectionnee();
switch(couleurBubble){
case R.color.c1: msg.setBackgroundResource(R.drawable.user_color1); break;
case R.color.c2: msg.setBackgroundResource(R.drawable.user_color2); break;
case R.color.c3: msg.setBackgroundResource(R.drawable.user_color3); break;
case R.color.c4: msg.setBackgroundResource(R.drawable.user_color4); break;
case R.color.c5: msg.setBackgroundResource(R.drawable.user_color5); break;
case R.color.c6: msg.setBackgroundResource(R.drawable.user_color6); break;
case R.color.c7: msg.setBackgroundResource(R.drawable.user_color7); break;
case R.color.c8: msg.setBackgroundResource(R.drawable.user_color8); break;
default: break;
}
parent_layout.setGravity(Gravity.RIGHT);
}
// If not mine then align to left
else {
layout.setGravity(Gravity.LEFT);
msg.setBackgroundResource(R.drawable.bot_chat);
parent_layout.setGravity(Gravity.LEFT);
}
return vi;
}
I don't really know where to go from here so any kind of help would be appreciated. If you want me to provide more code, let me know and I will.
Thank you.
I'm sharing how I would do it. Maybe, this can help you.
There's some strange issue because you are calling notifyDataSetChanged(). This would be enough to re-draw all message bubbles.
My ideia is:
Add a int variable to the adapter class (mColorResource). This variable will point to the proper drawable that should be used (like R.drawable.user_color1).
public class ChatAdapter extends BaseAdapter {
int mColorResource;
ChatAdapter(Activity activity, ArrayList<ChatData> list, int initialColorResource) {
mContext = activity;
chatMessageList = list;
inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// You must receive the color on the construtor
mColorResource = initialColor;
}
// Use this method to update the color (when user select a new color)
public void setColor(int newColorResource) {
mColorResource = newColorResource;
}
public View getView(int position, View convertView, ViewGroup parent) {
...
// Note how this if-else is cleaner now
if (message.isMine) {
layout.setGravity(Gravity.RIGHT);
msg.setBackgroundResource(mColorResource);
parent_layout.setGravity(Gravity.RIGHT);
} else {
layout.setGravity(Gravity.LEFT);
msg.setBackgroundResource(R.drawable.bot_chat);
parent_layout.setGravity(Gravity.LEFT);
}
...
}
}
Then, when a color is selected, find the proper drawable based on the view clicked and pass it to the adapter:
ItemColor1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v){
Toast.makeText(activity, "Couleur mise à jour", Toast.LENGTH_SHORT).show();
currentTheme = position;
SharedPreferences.Editor editor = pref.edit();
editor.putInt("indexColorSelected", currentTheme);
editor.apply();
// Here, you send the proper drawable...
// I'm not sure how you convert color selected to the drawable
// So, add your logic to convert the button clicked to a drawable here
// like R.drawable.user_color1
chatAdapter.setColor(R.drawable.NAME_OF_THE_COLOR);
// Request to re-draw all items from the list (all bubbles)
chatAdapter.notifyDataSetChanged();
}
});
Also, on your activity, you create the adapter with the last used color. Something like:
#Override
protected void onCreate(#Nullable final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
....
// Set a default color (if user is open you app for the first time)
int chatColor = R.drawable.user_color1;
// Add your logic to read the shared preference and convert that last color used to a valid drawable.
// Like chatColor = pref.getInt(indexColorSelected, R.drawable.user_color1) etc....
// Set the color in the adapter.
chatAdapter = newAdapter(this, mChatDataList, chatColor);
}
What I want to do is to show the same selected items on a recycler view even after the activity has been closed and only change items color when I again click on it. For now I have achieved changing the color on click but the state doesn't get saved?
This is my adapter:
public class LightsRecyclerViewAdapter extends
RecyclerView.Adapter<LightsRecyclerViewAdapter.ViewHolder> {
// private List<Integer> mViewColors;
private List<String> mAnimals;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
LightsRecyclerViewAdapter(Context context, List<String>
animals) {
this.mInflater = LayoutInflater.from(context);
this.mAnimals = animals;
}
// inflates the row layout from xml when needed
#Override
#NonNull
public ViewHolder onCreateViewHolder(#NonNull ViewGroup
parent, int viewType) {
View view = mInflater.inflate(R.layout.item, parent,
false);
return new ViewHolder(view);
}
// binds the data to the view and textview in each row
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int
position) {
// int color = mViewColors.get(position);
String animal = mAnimals.get(position);
// holder.myView.setBackgroundColor(color);
holder.myTextView.setText(animal);
}
// total number of rows
#Override
public int getItemCount() {
return mAnimals.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder
implements View.OnClickListener {
View myView;
TextView myTextView;
ViewHolder(View itemView) {
super(itemView);
// myView = itemView.findViewById(R.id.colorView);
myTextView =
itemView.findViewById(R.id.tvAnimalName);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
if (mClickListener != null)
mClickListener.onItemClick(view, getAdapterPosition());
}
}
// convenience method for getting data at click position
public String getItem(int id) {
return mAnimals.get(id);
}
// allows clicks events to be caught
public void setClickListener(ItemClickListener
itemClickListener) {
this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
}
And this is my activity:
public class DevicesList extends AppCompatActivity implements
LightsRecyclerViewAdapter.ItemClickListener{
private LightsRecyclerViewAdapter adapter,adapter1;
TextView title;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_devices_list);
title = (TextView)findViewById(R.id.textGrid);
// data to populate the RecyclerView with
ArrayList<Integer> viewColors = new ArrayList<>();
viewColors.add(Color.BLUE);
viewColors.add(Color.YELLOW);
viewColors.add(Color.MAGENTA);
viewColors.add(Color.RED);
viewColors.add(Color.BLACK);
ArrayList<String> Lab1LightsList = new ArrayList<>();
Lab1LightsList.add("Light 1");
Lab1LightsList.add("Light 2");
Lab1LightsList.add("Light 3");
Lab1LightsList.add("Light 4");
Lab1LightsList.add("Light 5");
ArrayList<String> Lab1ACList = new ArrayList<>();
Lab1ACList.add("AC 1");
Lab1ACList.add("AC 2");
Lab1ACList.add("AC 3");
Lab1ACList.add("AC 4");
Lab1ACList.add("AC 5");
ArrayList<String> Lab2LightsList = new ArrayList<>();
Lab2LightsList.add("Light 1");
Lab2LightsList.add("Light 2");
Lab2LightsList.add("Light 3");
Lab2LightsList.add("Light 4");
Lab2LightsList.add("Light 5");
Lab2LightsList.add("Light 6");
ArrayList<String> Lab2ACList = new ArrayList<>();
Lab2ACList.add("AC 1");
Lab2ACList.add("AC 2");
Lab2ACList.add("AC 3");
Lab2ACList.add("AC 4");
// set up the RecyclerView
RecyclerView recyclerView = findViewById(R.id.list1);
RecyclerView recyclerView1 =findViewById(R.id.list2);
LinearLayoutManager horizontalLayoutManagaer
= new LinearLayoutManager(DevicesList.this, LinearLayoutManager.HORIZONTAL, false);
LinearLayoutManager horizontalLayoutManager
= new LinearLayoutManager(DevicesList.this, LinearLayoutManager.HORIZONTAL, false);
recyclerView.setLayoutManager(horizontalLayoutManagaer);
recyclerView1.setLayoutManager(horizontalLayoutManager);
Intent mIntent = getIntent();
int intValue = mIntent.getIntExtra("labno", 0);
if(intValue==0) {
adapter = new LightsRecyclerViewAdapter(this, Lab1LightsList);
adapter1 = new LightsRecyclerViewAdapter(this, Lab1ACList);
adapter.setClickListener(this);
adapter1.setClickListener(this);
recyclerView.setAdapter(adapter);
recyclerView1.setAdapter(adapter1);
}
if(intValue==1) {
adapter = new LightsRecyclerViewAdapter(this, Lab2LightsList);
adapter1 = new LightsRecyclerViewAdapter(this, Lab2ACList);
adapter.setClickListener(this);
adapter1.setClickListener(this);
recyclerView.setAdapter(adapter);
recyclerView1.setAdapter(adapter1);
}
}
#Override
public void onItemClick(View view, int position) {
Toast.makeText(this, "You clicked " +
adapter.getItem(position) + " on item position " + position,
Toast.LENGTH_SHORT).show();
view.setBackgroundColor(getResources().getColor(R.color.colorPrimaryDark));
}
}
Please help on this.
Create one selected item position list and store it in prefs when an app goes to background or closed. Load that list when launching an app and compare that list in an adapter's onBindViewHolder's position parameter and marks it selected/unselected based on a comparison.
As per my understandings about your question, you want to save the state of the selected items even after the app is closed, and then you want to reload it whenever the app is launched again. You need to refer to this link Android Save Data
For the above solution, there can be various ways to save state, I am mentioning a few below:
Use SQLite Database to save the selected items. Then, whenever the app is loaded, fetch all the selected data from the DB and then mark them selected with whatever colour you want on the list.
You can also use Shared Preferences, to store the selection. And, same as above, you can reload the data when the app is launched.
You can also store the data in a specific format, maybe CSV, JSON, XML etc., in a file and save it either in Internal Storage or External Storage of the device. And when the app is launched, fetch all the selected values from the file and process accordingly.
You can also use a web server, Firebase Storage, or other cloud storage services to save the data and then fetch the data on new app launch.
Do note: All these techniques require you to save the state before the app is closed. So it is better to store the states, either on click of the item, or onPause method of the activity.
If you face any problems with these solutions, you can post another comment and I will give it a look.
Save these clicked item position in a hashmap in Shareprefence. suppose u close the activity after u coming back the activity just pass the saved list with ur data in adapter and compare the shareprefence list with ur data list if position or data match than make the itemview layout colored.
// save clicked item is a list and save it sharePreference.
List<Integer> clikedList = new ArrayList<>();
if (clicked item){
ClikedList.add(position)
}
String value = gson.toJson(list);
SharedPreferences prefs = context.getSharedPreferences("mylist",
Context.MODE_PRIVATE);
Editor e = prefs.edit();
e.putString("list", value);
e.commit();
// for getting cliked position list from SharePreference
SharedPreferences prefs = context.getSharedPreferences("mylist",
Context.MODE_PRIVATE);
String value = prefs.getString("list", null);
GsonBuilder gsonb = new GsonBuilder();
Gson gson = gsonb.create();
MyObject[] list = gson.fromJson(value, MyObject[].class);
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
// suppose clicked position 4 u get from shaved cliked list
in here u neddd to retreive cliked list position and clored those item
int select = 4;
if (select == position) {
holder.itemView.setBackgroundColor(Color.BLUE);
Toast.makeText(context, "" + position, Toast.LENGTH_SHORT).show();
} else {
holder.itemView.setBackgroundColor(Color.parseColor("#214F4B"));
Toast.makeText(context, "" + position, Toast.LENGTH_SHORT).show();
}
holder.tv_title.setText(data.get(position));
}
I'm currently following this tutorial to implement a shared element transition between view (cards) in RecyclerView and activity but I'm not sure how can I do it since I'm using an onClickListener on MyRecyclerAdapter class to start a new activity.
Just new in development, hope you can help me about it.
MyRecyclerAdapter.java
public class MyRecyclerAdapter extends RecyclerView.Adapter<PaletteViewHolder> {
private Context context;
private List<Palette> palettes;
public MyRecyclerAdapter(Context context, List<Palette> palettes) {
this.palettes = new ArrayList<Palette>();
this.palettes.addAll(palettes);
this.context = context;
}
#Override
public PaletteViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.
from(viewGroup.getContext()).
inflate(R.layout.card_view, viewGroup, false);
itemView.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(context, ScrollingActivity.class);
intent.putExtra("P25", "Longanissa");
context.startActivity(intent);
}
});
return new PaletteViewHolder(itemView);
}
#Override
public void onBindViewHolder(PaletteViewHolder paletteViewHolder, int i) {
Palette palette = palettes.get(i);
paletteViewHolder.titleText.setText(palette.getName());
paletteViewHolder.contentText.setText(palette.getHexValue());
paletteViewHolder.card.setCardBackgroundColor(palette.getIntValue());
}
#Override
public int getItemCount() {
return palettes.size();
}
animateIntent method:
public void animateIntent(View view) {
// Ordinary Intent for launching a new activity
Intent intent = new Intent(this, YourSecondActivity.class);
// Get the transition name from the string
String transitionName = getString(R.string.transition_string);
// Define the view that the animation will start from
View viewStart = findViewById(R.id.card_view);
ActivityOptionsCompat options =
ActivityOptionsCompat.makeSceneTransitionAnimation(this,
viewStart, // Starting view
transitionName // The String
);
//Start the Intent
ActivityCompat.startActivity(this, intent, options.toBundle());
You need to set the transition name of the view inside the onBindViewHolder. It needs to be different of the others viewHolder so get a way to make it different and unique (using palette.getName() if palette names are unique for example or use i).
Then you need to start the activity inside on click using the provided view:
ActivityOptionsCompat options = ActivityOptionsCompat.makeSceneTransitionAnimation(context, v, v.getTransitionName());
context.startActivity(intent, options.toBundle());
I don't understand why you need animateIntent method. Hope it still helps
This question has been answered before, but the solutions doesn't seem to work for me. I would like to know what the best way is to save an ArrayList.
I generate an ArrayList with all the installed applications on the phone. This list is shown in a ListView where the user can (de)select apps. This is all working fine. What I would like is that the Arraylist gets saved when the user presses a save button or when the activity calls onPause().
When the user returns to the list the user will see the list the way he saved/left it.
Here is my code:
onCreate
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_app_list);
loadApps();
loadListView();
addClickListener();
}
loadApps
private void loadApps(){
manager = getPackageManager();
apps = new ArrayList<AppDetail>();
if(apps.size()==0) {
Intent i = new Intent(Intent.ACTION_MAIN, null);
i.addCategory(Intent.CATEGORY_LAUNCHER);
List<ResolveInfo> availableActivities = manager.queryIntentActivities(i, 0);
for (ResolveInfo ri : availableActivities) {
AppDetail app = new AppDetail();
app.label = ri.loadLabel(manager);
app.name = ri.activityInfo.packageName;
app.icon = ri.activityInfo.loadIcon(manager);
app.allowed = false;
apps.add(app);
}
Log.i("applist", apps.toString());
}
}
AppDetail.class
public class AppDetail {
CharSequence label;
CharSequence name;
Drawable icon;
Boolean allowed;
loadListView
private void loadListView(){
list = (ListView)findViewById(R.id.apps_list);
adapter = new ArrayAdapter<AppDetail>(this, R.layout.list_item, apps) {
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null){
convertView = getLayoutInflater().inflate(R.layout.list_item, null);
}
ImageView appIcon = (ImageView)convertView.findViewById(R.id.item_app_icon);
appIcon.setImageDrawable(apps.get(position).icon);
TextView appLabel = (TextView)convertView.findViewById(R.id.item_app_label);
appLabel.setText(apps.get(position).label);
TextView appName = (TextView)convertView.findViewById(R.id.item_app_name);
appName.setText(apps.get(position).name);
if(list.isItemChecked(position)){convertView.setBackgroundColor(getResources().getColor(R.color.green));}
if(!list.isItemChecked(position)){convertView.setBackgroundColor(getResources().getColor(R.color.white));}
return convertView;
}
};
list.setAdapter(adapter);
list.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
}
addClickListener
private void addClickListener() {
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> av, View v, int pos,
long id) {
checked = list.getCheckedItemPositions();
ArrayList<AppDetail> allowedApps = new ArrayList<>();
for (int i = 0; i < checked.size(); i++) {
// Item position in adapter
int position = checked.keyAt(i);
// Add sport if it is checked i.e.) == TRUE!
if (checked.valueAt(i)) {
allowedApps.add(adapter.getItem(position));
}
}
adapter.notifyDataSetChanged();
Log.i("", allowedApps.toString());
}
});
}
At this moment I'm creating two lists:
List: list of all apps
AllowedApps: list of checked (allowed) apps, to use in an other activity
If you need saving your list when activity is paused, you have several ways to do it. First you need define the private list field in your activity.
private ArrayList<AppDetail> allowedApps;
1) Make AppDetail serializable and use onSaveInstanceState
public class AppDetail implements Serializable {
CharSequence label;
CharSequence name;
Drawable icon;
Boolean allowed;
}
---------------- EDIT -----------------
I would change Drawable icon field for int icon.
In your loadApps() method change the setence app.icon = ri.activityInfo.getIconResource();
In yout loadListView method change the setence appIcon.setImageResource(apps.get(position).icon);
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putSerializable("allowedApps", allowedApps);
}
Retrieve the list in onCreate method
if (savedInstanceState != null) {
allowedApps = (List<AppDetail>)savedInstanceState.getSerializable("allowedApps");
}else{
allowedApps = new ArrayList<AppDetail>();
}
2) Use onRetainCustomNonConfigurationInstance
Return the list in onRetainCustomNonConfigurationInstance
#Override
public Object onRetainCustomNonConfigurationInstance() {
return allowedApps;
}
Retrieve the list in onCreate method
Object allowedApps= getLastCustomNonConfigurationInstance();
if (allowedApps != null) {
this.allowedApps = (List<AppDetail>) allowedApps;
}else{
this.allowedApps = new ArrayList<AppDetail>();
}
I think you are looking for something like "Parcelable". It can save any ArrayList and retrieve back when you need it just like the Shared Preferences.
Please have a look here,
How to save custom ArrayList on Android screen rotate?
ArrayList is serializable. Save it as a serializable object in file on storage