When app starts at first, start Activity with two button: Create File and Settings. Then if I click on button Create File - start Activity where I write text and save in file.
If we have error when file saved - start activity with two button. Else start another Activity with three buttons: Look file, Edit File, Settings.
How organize correct transitions between this Activity and How start activity with three buttons if file already saved?
public class MainFirstActivity extends AppCompatActivity {
private Button createFile;
private Button settings;
private boolean start = true;
private static final String MY_SETTINGS = "my_settings";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_first);
createFile = (Button) findViewById(R.id.create_file);
settings = (Button) findViewById(R.id.settings);
createFile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainFirstActivity.this, CreateFileActivity.class);
startActivity(intent);
// MainFirstActivity.this.finish();
}
});
settings.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainFirstActivity.this, SettingActivity.class);
startActivity(intent);
}
});
}
#Override
protected void onResume() {
super.onResume();
File f = new File(CreateFileActivity.FILE_NAME);
if(!f.exists() && !f.isDirectory() && start) {
Intent intent = new Intent(MainFirstActivity.this, MainWithFileActivity.class);
startActivity(intent);
//start=false;
MainFirstActivity.this.finish();
Log.e("err", "intent");
}
}
}
MainWithFileActivity
public class MainWithFileActivity extends AppCompatActivity {
public static final String MY_SETTINGS = "MY_SETTINGS";
private Button lookFile;
private Button editFile;
private Button settings;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_if_first);
lookFile = (Button) findViewById(R.id.look_file);
settings = (Button) findViewById(R.id.settings);
editFile = (Button) findViewById(R.id.edit_file);
lookFile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainWithFileActivity.this, LookFileActivity.class);
startActivity(intent);
}
});
editFile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainWithFileActivity.this,CreateFileActivity.class);
startActivity(intent);
}
});
settings.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainWithFileActivity.this, SettingActivity.class);
startActivity(intent);
}
});
}
}
Simply check if the file exists. If it does not, hide the lookFile button
Add this in your MainWithFileActivity onCreate method
File f = new File(CreateFileActivity.FILE_NAME);
if(!f.exists() && !f.isDirectory()) {
lookFile.setVisibility(View.GONE);
}
Related
SubActivity cannot INVISIBLE the button in MainActivity I tried to use intent, but I'm not sure.
it SubActivity java code
try to INSIBLE the resetB button in Sub Activity
public class SubActivity extends Activity {
Button resetH, resetH2;
Button resetB, miC;
#SuppressLint("MissingInflatedId")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sub);
ImageButton back = (ImageButton) findViewById(R.id.back);
resetH = (Button) findViewById(R.id.resetH);
resetH2 = (Button) findViewById(R.id.resetH2);
resetB = findViewById(R.id.resetB);
resetH.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View view) {
resetB.setVisibility(View.VISIBLE);
}
});
resetH.setOnClickListener(new Button.OnClickListener() {
#Override
public void onClick(View view) {
resetB.setVisibility(View.INVISIBLE);
}
});
back.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
}
});
I used intent, but I can't move the button
So I am new and working on an app, so I have created homepage of it and then when we click on anyone of it it opens a new activity in which when clicking the button to get the answer doesnt work and it goes back to the homepage. Please help me solve this!
This is my code of main activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CardView Currency = (CardView) findViewById(R.id.Currency);
CardView Area = (CardView) findViewById(R.id.Area);
CardView Length = (CardView) findViewById(R.id.Length);
CardView Temperature = (CardView) findViewById(R.id.Temperature);
CardView Time = (CardView) findViewById(R.id.Time);
CardView Weight = (CardView) findViewById(R.id.Weight);
Currency.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Currency.class);
startActivity(intent);
}
});
Weight.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Weight.class);
startActivity(intent);
}
});
Time.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Time.class);
startActivity(intent);
}
});
Length.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Length.class);
startActivity(intent);
}
});
Area.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Area.class);
startActivity(intent);
}
});
Temperature.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Temperature.class);
startActivity(intent);
}
});
}
And this is of my new activity to open at homepage and convert the value
public class Weight extends AppCompatActivity {
private TextView textView;
private Button button;
private EditText editText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_weight);
button = findViewById(R.id.button);
textView = findViewById(R.id.textView);
editText = findViewById(R.id.editText);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Toast.makeText(Weight.this, "Request Proceeded", Toast.LENGTH_SHORT).show();
String s = editText.getText().toString();
Integer.parseInt(s);
int kg = Integer.parseInt(s);
double pound = 2.205 * kg;
textView.setText("The corresponding value in Pound is" + pound);
}
});
}
I'm making an Android app and in my app, I add the feature of storing the login state.
My Splash screen:
public class Splash extends AppCompatActivity {
private SharedPreferences preferences;
public int a = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressbar);
new CountDownTimer(5000, 1000) {
#Override
public void onTick(long millisUntilFinished) {
a = a + 1;
progressBar.setProgress(a);
}
#Override
public void onFinish() {
SharedPreferences preferences = getSharedPreferences("login", MODE_PRIVATE);
String check = preferences.getString("login", "off");
if (check.equals("on")) {
startActivity(new Intent(Splash.this, Menu.class));
} else {
startActivity(new Intent(Splash.this, LoginPage.class));
}
}
}.start();
} }
My Login screen:
public class LoginPage extends AppCompatActivity {
private SharedPreferences preferences;
Context context;
Button login, register, database;
EditText username;
EditText password;
TextView msg;
MyDBManager db;
static final int REGISTRATION_REQUEST = 1; // The request code
#Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loginpage);
db = new MyDBManager(this);
msg = (TextView) findViewById(R.id.msg);
login = (Button) findViewById(R.id.button);
register = (Button) findViewById(R.id.button2);
database = (Button) findViewById(R.id.button3);
username = (EditText) findViewById(R.id.user);
password = (EditText) findViewById(R.id.pass);
// Click and move to the next activity
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
db.open();
Cursor c = db.getUser(username.getText().toString(), password.getText().toString());
if (c.moveToFirst()) {
db.close();
context.startActivity(new Intent(context,Menu.class));
// Intent i=new Intent(getApplicationContext(),Menu.class); //
i.putExtra("Username", username.getText().toString()); //
startActivity(i); // call Login Activity
Store();
}
else
{
db.close();
// set error message when the username and/or password is not valid
msg.setText("Unable to login: wrong username or password!");
// Stay at the current activity.
}
}
private void Store() {
SharedPreferences preferences=context.getSharedPreferences("login",Context.MODE_PRIVATE);
SharedPreferences.Editor editor=preferences.edit();
editor.putString("login_status","on");
editor.commit();
}
});
// Click and move to the next activity
register.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(LoginPage.this, Registration.class);
startActivityForResult(intent, REGISTRATION_REQUEST);
}
});
// Click and move to the next activity
database.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(LoginPage.this, Database.class);
startActivity(intent);
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REGISTRATION_REQUEST) {
//if(resultCode == Registration.RESULT_OK){
Log.d("Pikatchu", "User successfully registered!");
Bundle res = data.getExtras();
String result = res.getString("result");
System.out.println(result);
msg.setText(result);
}
}
}
My Menu screen:
public class Menu extends AppCompatActivity {
private SharedPreferences preferences;
Button startJourney, displayJourneys;
TextView msg; // where to display the name of the user
Button buttonLogout ;
/* the string is where to store data when we select something */
String db_username;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu);
buttonLogout = (Button) findViewById(R.id.btn_logout);
msg = (TextView) findViewById(R.id.msg);
startJourney = (Button) findViewById(R.id.recordingmode);
// Bundle bundle = getIntent().getExtras(); //
db_username = (bundle.getString("Username")); //// //// // Set
Welcome message to the user who logged in //
msg.setText("Welcome "+db_username);
// Click and move to the next activity // startJourney.setOnClickListener(new View.OnClickListener() { //
#Override // public void onClick(View v) { //
Intent intent = new Intent(Menu.this, Recordingmode.class); //
intent.putExtra("Username", db_username); //
startActivity(intent); // } // });
// Click and move to the next activity buttonLogout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SharedPreferences preferences=getSharedPreferences("login", Context.MODE_PRIVATE);
SharedPreferences.Editor editor=preferences.edit();
editor.putString("login_status","off");
editor.commit();
finish();
moveTaskToBack(true);
} });
}
}
But if I login in the app, the error is thrown:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null
object reference
From the first activity I would like to go to the second, then from the second to the third. In the third activity I would like to enter the name in EditText, then after pressing the button, go to the first activity and at the same time send the information entered in the third activity.
Unfortunately, after pressing the button in the third activity, instead of returning to the first activity, I return to the second activity. Was the first activity killed? What could I do to ensure that the information is correct for the first activity? This is my code:
First:
public class MainActivity extends AppCompatActivity {
TextView textViewInformation;
Button button_GoToSecond;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textViewInformation = findViewById(R.id.textView);
button_GoToSecond = findViewById(R.id.button);
button_GoToSecond.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(MainActivity.this, Second.class);
startActivity(i);
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent i) {
if((requestCode == 1) &&(resultCode == RESULT_OK)) {
String name = i.getStringExtra("name");
textViewInformation.setText(name);
}
}
}
Second:
public class Second extends AppCompatActivity {
Button button_GoToThird;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
button_GoToThird = findViewById(R.id.button2);
button_GoToThird.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(Second.this, Third.class);
startActivity(i);
}
});
}
}
Third:
public class Third extends AppCompatActivity {
EditText editText_Data;
Button button_SendData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_third);
editText_Data = findViewById(R.id.editText);
button_SendData = findViewById(R.id.button3);
button_SendData.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
finish();
}
});
}
public void finish() {
String name;
name = editText_Data.getText().toString();
Intent i = new Intent(Third.this, MainActivity.class);
i.putExtra("name", name);
setResult(RESULT_OK, i);
super.finish();
}
}
just remove finish(); thats it
The reason that it goes to the second activity is because of this:
button_SendData.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
finish();
}
});
public void finish() {
String name;
name = editText_Data.getText().toString();
Intent i = new Intent(Third.this, MainActivity.class);
i.putExtra("name", name);
setResult(RESULT_OK, i);
super.finish(); //This kills the current activity.
}
You should do:
public void finish() {
String name;
name = editText_Data.getText().toString();
Intent i = new Intent(Third.this, MainActivity.class);
Bundle bundle = new Bundle();
bundle.putString("name", name);
startActivityForResult(i, RESULT_OK, bundle);
}
#Override
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent i) {
if((requestCode == 1) &&(resultCode == RESULT_OK)) {
Bundle bundle = i.getExtras();
String name = bundle.getString("name");
textViewInformation.setText(name);
}
}
When you call finish, it just kills the current activity. If you want to go back to the first activity, just start a new activity for the first activity and pass the data in a Bundle.
If you want to have more of a stack concept, you can use Fragments.
public class FullscreenActivity extends AppCompatActivity {
private ImageButton act;
private ImageButton sat;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fullscreen);
act = (ImageButton) findViewById(R.id.act);
sat = (ImageButton) findViewById(R.id.sat);
sat.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent intent = new Intent(FullscreenActivity.this, sat.class);
startActivity(intent);
act.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent intent = new Intent(FullscreenActivity.this, act.class);
startActivity(intent);
}
});
}}
What am I doing worng. I have a main UI with six imagebuttons, each one linking to a different activity. How can I link then all in the main activity which is called fullscreen activity
I think you want to bring the FullScreenActivity to front so you only have to finish the front Activity because you didn't finish it
just do finish(); on your sat.class or act.class
or....
You can do this too on your sat.class or act.class:
Intent i = new Intent(this, FullScreenActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(i);
act.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent intent = new Intent(FullscreenActivity.this, act.class);
startActivity(intent);
}
});
why is the above part inside some other button's click listener? Move it outside the anonymous inner method like
sat.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent intent = new Intent(FullscreenActivity.this, sat.class);
startActivity(intent);
}
});
act.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent intent = new Intent(FullscreenActivity.this, act.class);
startActivity(intent);
}
});