Is there a way to make an alert only appear when the app is opened? I'm creating an alert in onStart() in my MainActivity and whenever I go back to that activity in the app, it shows the alert again which can be annoying to the user. Or is there a way to create a "got it" button and then turn off the alert? Here is my code:
protected void onStart() {
super.onStart();
new AlertDialog.Builder(this)
.setTitle("Instructions")
.setMessage("Hello! To begin, select a map from the list to train with. Make sure" +
" you are on the correct floor.")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
})
.setIcon(R.drawable.ic_launcher)
.show();
}
This is because when another activity comes to foreground upon your MainActivity makes your activity goes to OnPause().
Then when you go back to your MainActivity. The system calls
onStart() again. See The activity life cycle
-First Solution
public class TestActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
showAlertDialog();
}
}
private void showAlertDialog() {
// code to show alert dialog.
}
}
-Second Solution
public class TestActivity extends ActionBarActivity {
private static boolean isAlertDialogShownBefore = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (!isAlertDialogShownBefore) {
showAlertDialog();
isAlertDialogShownBefore = true;
}
}
private void showAlertDialog() {
// code to show alert dialog.
}
#Override
public void onBackPressed() {
isAlertDialogShownBefore = false;
super.onBackPressed();
}
}
Put that code in onCreate method of your activity. Check for saveInstanceState for null, if it is then show your alertDialog
Related
I am working on an Android application which requires constant listener of Internet connectivity. I am using Broadcast listener and successfully applied it. But my code only shows the Toast message.
I want to stop the current activity and show a default XML file which says "No Internet Connection". and whenever it connect the Internet, previous activity resumes.
ExampleBradcastReceiver.java
public class ExampleBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
boolean noConnectivity = intent.getBooleanExtra(
ConnectivityManager.EXTRA_NO_CONNECTIVITY, false
);
if (noConnectivity) {
Toast.makeText(context, "Disconnected", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "Connected", Toast.LENGTH_SHORT).show();
}
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
ExampleBroadcastReceiver exampleBroadcastReceiver = new ExampleBroadcastReceiver();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
protected void onStart() {
super.onStart();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(exampleBroadcastReceiver, filter);
}
#Override
protected void onStop() {
super.onStop();
unregisterReceiver(exampleBroadcastReceiver);
}
}
In the place of Toast Message, I want to show a default XML file whenever disconnected and resume activity whenever connected.
You can move ExampleBroadcastReceiver to MainActivity as an inner class. And since in Java inner classes have access to their parent classes' methods and fields, you can in onReceive method consider showing/hiding the Internet disconnected view.
public class MainActivity extends AppCompatActivity {
ExampleBroadcastReceiver exampleBroadcastReceiver = new ExampleBroadcastReceiver();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
protected void onStart() {
super.onStart();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(exampleBroadcastReceiver, filter);
}
#Override
protected void onStop() {
super.onStop();
unregisterReceiver(exampleBroadcastReceiver);
}
private void showInternetDisconnectedView(boolean disconnected){
// show or hide based on 'disconnected'
}
private class ExampleBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
boolean noConnectivity = intent.getBooleanExtra(
ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
showInternetDisconnectedView(noConnectivity);
}
}
}
}
You need to move Broadcast receiver code into Activity and on receiving internet connection events you can stop current in progress activity and make internet failure layout visible there only as it is part of Activity class. If it is required through out the Application, then create Base activity and handle this there to avoid duplicating code on every screen.
I am a beginner in android app development.. i have made an app now and there is a pop up in it which shows a persons name and details.. i have added 3 buttons there like CALL,SMS,EMAIL.. i went for call activity, but its not working. no error is there still call button is not making calls.. The same code i have tried in a new project, there it works well.. but when i do it on that popup, call is not working... please help me
public class popupinv extends AppCompatActivity {
public Button b;
public void init(){
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_popupinv);
init();
b= (Button) findViewById(R.id.call);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent callIntent=new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse("tel:123456));
startActivity(callIntent);
}
});
}
}
I'm making an Android whack a mole game. I have the main activity which is basically the launcher, when you press the Play button the game activity starts. This works fine as it shows the background image and all molehills but I don't know how to call the method to start the game.
I've tried to call it from inside onCreate() but this ends up "playing the game" itself.
I've tried to call it right after the startActivity(intent) but the app crashes. And also I've tried to create an instance of the game class and call the play() method after the start activity but it doesn't work aswell. I don't know how to start the game method once the game activity is loaded.
I hope I explained well, thank you.
public class MainActivity extends AppCompatActivity {
ImageButton btnStart;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hide TitleBar
try { this.getSupportActionBar().hide();}
catch (NullPointerException e){}
setContentView(R.layout.activity_main);
btnStart = (ImageButton)findViewById(R.id.btnStart);
btnStart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(), GameView.class);
startActivity(intent);
}
});
}
And this is the code for the game_activity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hide TitleBar
try { this.getSupportActionBar().hide();}
catch (NullPointerException e){}
setContentView(R.layout.activity_game_view);
game();
}
The game() method is a typical game loop.
public void game() {
Random random = new Random();
int index;
/*
* Casting array to store all ImageView on the game
*/
imgViewArray[0] = (ImageView)findViewById(R.id.img1);
imgViewArray[1] = (ImageView)findViewById(R.id.img2);
imgViewArray[2] = (ImageView)findViewById(R.id.img3);
imgViewArray[3] = (ImageView)findViewById(R.id.img4);
imgViewArray[4] = (ImageView)findViewById(R.id.img5);
imgViewArray[5] = (ImageView)findViewById(R.id.img6);
imgViewArray[6] = (ImageView)findViewById(R.id.img7);
imgViewArray[7] = (ImageView)findViewById(R.id.img8);
imgViewArray[8] = (ImageView)findViewById(R.id.img9);
imgViewArray[9] = (ImageView)findViewById(R.id.img10);
int j=0;
while (j < 10) {
// Get a random image to animate
index = random.nextInt(10);
switch(index) {
case 0: imgViewArray[0].setImageResource(images[6]);
new java.util.Timer().schedule(
new java.util.TimerTask() {
#Override
public void run() {
imgViewArray[0].setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
imgViewArray[0].setImageResource(images[0]);
}
});
}
},
300 // The code executes after 300ms
);
break;
I think you should put the game() call inside onResume().
There are many ways to solve the problem:
Using EventBus
Send the start game Event from Main Activity and register for the Event in the Game activity.
This is my favorite way to handle the problem. It's because the simplicity and prevent us from tightly coupled code. The major problem with using EventBus is we will lost in the sea of Event if there are too much Event in the the app.
How to do:
First, create the Event. This is just a simple class:
public class StartGameEvent {
}
Second, register for the event in the game activity:
public class GameActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
EventBus.getDefault().register(this);
}
protected void onDestroy() {
super.onDestroy();
EventBus.getDefault().unregister(this);
}
}
Third, subscribe for the event:
public class GameActivity extends Activity {
...
#Subscribe
public void onMessageEvent(StartGameEvent event) {
game();
}
}
Last, send the event from Main activity:
EventBus.getDefault().post(new StartGameEvent());
Using LocalBroadcastManager
You need to create the message and broadcast it in from your Main activity:
Intent intent = new Intent("playEvent");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
Then, in the game activity, you need to register as receiver:
#Override
public void onCreate(Bundle savedInstanceState) {
// register for the event
LocalBroadcastManager.getInstance(this).registerReceiver(mReceiver,
new IntentFilter("playEvent"));
}
private BroadcastReceiver mReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
game();
}
};
#Override
protected void onDestroy() {
// Unregister here
LocalBroadcastManager.getInstance(this)
.unregisterReceiver(mReceiver);
super.onDestroy();
}
I slightly modifying the code from How to use LocalBroadcastManager? for your case.
Using a static method in Game activity
This is the simplest way but highly discouraged. Because we can't ensure the state of the activity. Do not use this in production code. This is for learning sake only.
You can make the game() method as a static method like this:
public class GameActivity extends Activity {
...
public static void game() {
// game logic.
}
}
Then call the method when you want with:
GameActivity.game();
How to get result of background process in any Activity?
I'm working with OTA update. App handle that in background with handler. When update is done I have to show alert dialog to the user. I can show it in SettingsActivity where I start with OTA but user can be in any other Activity.
private void checkIsUpdated() {
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
mDevice.getDevice().read(GattUUID.LS_DEVICE_INFORMATION, GattUUID.LC_FIRMWARE, new
BleDevice.ReadWriteListener() {
#Override
public void onEvent(ReadWriteEvent e) {
if (e.wasSuccess()) {
if (firmwareVersion.equals(e.data_string())) {
showAlertDialog("OTA update failed", "Device is not updated");
} else {
showAlertDialog("OTA update is successful.\nDevice is updated to new " +
"firmware!", "Device is updated");
}
Log.i("OTA", "Read firmware is new success");
} else {
Log.e("OTA", "Read firmware is new success");
}
}
});
}
}, 30000);
}
AlertDialog code
private void showAlertDialog(String message, String title) {
AlertDialog.Builder builder = new AlertDialog.Builder(mContext, R.style.SwipeDialogLight);
builder.setTitle(title)
.setMessage(message)
.setCancelable(false)
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
AlertDialog alert = builder.create();
if (!alert.isShowing()) {
alert.show();
}
}
As #W4R10CK stated, I thought that too. The BroadcastReceiver might not a very good idea. But later, I gave a thought about it and if you call checkIsUpdated function inside a Service and send the Broadcast from it, it might be a feasible solution.
So basically you need a BaseActivity class and in which you need to have a BroadcastReceiver. You need to register it onResume and again unregister it onPause.
And you need to have an abstract method to be overriden in each of your Activity too.
So your BaseActivity may look like this..
public abstract class BaseActivity extends AppCompatActivity {
private final Context context;
public BaseActivity() {
this.context = setContext();
}
protected abstract Context setContext();
#Override
public void onResume() {
super.onResume();
registerBroadcastReceiver();
}
#Override
public void onPause() {
super.onPause();
unRegisterBroadcastReceiver();
}
// Declare your BroadcastReceiver here
private class MyBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
showAlertDialog(context);
}
}
}
As #rogerwar suggested in the comments, the correct approach is a broadcast receiver.
Vogella has a nice tutorial
Since you want to have it in all activities, you can make a base class for all your activities and in this base class you can register the receiver in the onStart and unregister it in the onStop.
I have an android application that in main activity(Home Page) I call a method and show a message. and when I go to other activity that message hides and again when come to Home page that will be shown. But I can not show this message again. I want to be show just for first time. How can I do this?
Try something like this:
public class TestActivity extends Activity {
static boolean msgShown = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (!msgShown)
{
Toast.makeText(this, "MyMsg", 1000);
msgShown = true;
}
}
}