Android Studio – DIGIDIMENSION

RecyclerView _ dynamic lists

DIGIDIMENSION — Tue, 20 Dec 2022 14:07:54 +0000

RecyclerView makes it easy to efficiently display large sets of data. You supply the data and define how each item looks, and the RecyclerView library dynamically creates the elements when they’re needed.

As the name implies, RecyclerView recycles those individual elements. When an item scrolls off the screen, RecyclerView doesn’t destroy its view. Instead, RecyclerView reuses the view for new items that have scrolled onscreen. This reuse vastly improves performance, improving your app’s responsiveness and reducing power consumption.

https://developer.android.com/guide/topics/ui/layout/recyclerview

Sample pictures

Java code

package com.example.recyclerview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    ArrayList contacts;
    RecyclerView recyclerView;
    ContactAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

         recyclerView = findViewById(R.id.rv_main);
         contacts = Contact.createContactsList(500);
         adapter = new ContactAdapter(contacts);

         recyclerView.setAdapter(adapter);
         recyclerView.setLayoutManager(new LinearLayoutManager(this));

    }
}

package com.example.recyclerview;

import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.TextView;

import java.util.ArrayList;

public class ContactAdapter extends RecyclerView.Adapter {


    private ArrayList contacts;

    public class MyViewHolder extends RecyclerView.ViewHolder {

        public TextView name;
        public CheckBox chBox;

        public MyViewHolder(@NonNull View itemView) {
            super(itemView);

            name = itemView.findViewById(R.id.rv_text);
            chBox = itemView.findViewById(R.id.rv_chk);
        }
    }

    public ContactAdapter(ArrayList contacts) {
        this.contacts = contacts;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
        View itemView = LayoutInflater.from(viewGroup.getContext()).
                inflate(R.layout.recycler_view, viewGroup, false);
        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder myViewHolder, int position) {

        Contact contact = contacts.get(position);
        myViewHolder.name.setText(contact.get_name());
        myViewHolder.chBox.setChecked(contact.get_state());
    }

    @Override
    public int getItemCount() {
        return contacts.size();
    }


}

package com.example.recyclerview;

import java.util.ArrayList;

public class Contact {
    private String _name;
    private boolean _state;

    public Contact(String name, boolean state) {
        _name = name;
        _state = state;
    }

    public String get_name() {
        return _name;
    }

    public boolean get_state() {
        return _state;
    }

    private static int lastContactId = 0;

    public static ArrayList createContactsList(int numContacts) {

        ArrayList contacts = new ArrayList<>();

        for (int i = 1; i <= numContacts; i++) {

            contacts.add(new Contact("person " + ++lastContactId, true));
        }

        return contacts;

    }
}

XML

Shared Preferences

DIGIDIMENSION — Mon, 19 Dec 2022 14:35:02 +0000

In this video, we create a simple application login activity in which we use SharedPreferences to save our username and password.

Sample pictures

Java code

package com.example.sharedpreference;

import android.content.Intent;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;

public class SplashScreen extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash_screen);

        StartAnim();

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {

                startActivity(new Intent(getApplicationContext(), LoginActivity.class));

            }
        }, 3000);
    }
    void StartAnim(){
        TextView ta = findViewById(R.id.splash_text);
        Animation zoomIn;
        zoomIn = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.zoom_in);
        ta.startAnimation(zoomIn);
    }

    @Override
    protected void onPause() {
        super.onPause();
        finish();
    }
}

package com.example.sharedpreference;

import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends AppCompatActivity {


    public SharedPreferences sharedPreferences;
    SharedPreferences.Editor editor;
    EditText et_name, et_pass;

    String name,pass,_name,_pass;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        RemoveToolbar();
        findView();

        sharedPreferences = getSharedPreferences("MyShared", MODE_PRIVATE);
        editor = sharedPreferences.edit();

    }
    void RemoveToolbar(){
        //Remove toolbar
        Window w = getWindow();
        w.setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS,
                WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
    }
    void findView() {
        et_name = findViewById(R.id.actv_log_user_name);
        et_pass = findViewById(R.id.actv_log_password);
    }


    public void LoginClick(View v) {

        name = sharedPreferences.getString("NAME", "");
        pass = sharedPreferences.getString("PASS", "");
        _name = et_name.getText().toString();
        _pass = et_pass.getText().toString();

        if(name.equals("") && pass.equals("")){

            Toast.makeText(this,"Please register",
                    Toast.LENGTH_SHORT).show();

        }
        else if (name .equals(_name) && pass.equals(_pass)) {

            Toast.makeText(this,"You have successfully logged in",
                    Toast.LENGTH_LONG).show();

            startActivity(new Intent(getApplicationContext(), MainActivity.class));

        }
        else {

            Toast.makeText(this,"Username or password incorrect",
                    Toast.LENGTH_SHORT).show();
        }

    }

    public void RegisterClick(View v) {

        name = sharedPreferences.getString("NAME", "");
        pass = sharedPreferences.getString("PASS", "");
        _name = et_name.getText().toString();
        _pass = et_pass.getText().toString();

        if (!name.equals("") && !pass.equals("")) {

            Toast.makeText(this, "You are already registered",
                    Toast.LENGTH_SHORT).show();

        }
        else if(!_name.equals("") && !_pass.equals("")){

            editor.putString("NAME", _name);
            editor.putString("PASS", _pass);
            editor.apply();
            editor.commit();

            Toast.makeText(this, "Save data",
                    Toast.LENGTH_SHORT).show();

            et_name.setText(null);
            et_pass.setText(null);
        }
        else {
            Toast.makeText(this, "Username or password fields are empty",
                    Toast.LENGTH_SHORT).show();
        }

    }


    public void ClearClick(View v) {

        editor.clear();
        editor.apply();
        editor.commit();
        Toast.makeText(getApplicationContext(), "Clear data",
                Toast.LENGTH_SHORT).show();
    }
}

XML

Login Screen

DIGIDIMENSION — Mon, 19 Dec 2022 14:01:47 +0000

Design a sample login page in Android Studio using linear layout.

Sample pictures

Java code

package com.example.Login;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;

public class Login extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

       //Remove toolbar
       // Window w = getWindow();
       // w.setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS,
       //           WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
    }
}

XML



    #008577
    #00574B
    #D81B60

    #A1857E80
    #1AB1AAAC
    #F5F56E07
    #FFFFFFFF


    Login
    Password
    LOGIN
    Create Account
    Need Help?
    User Name

Navigation drawer

DIGIDIMENSION — Sun, 18 Dec 2022 06:18:44 +0000

The navigation drawer is a UI panel that shows your app’s main navigation menu. The drawer appears when the user touches the drawer icon in the app bar or when the user swipes a finger from the left edge of the screen.
To add a navigation drawer, first declare a DrawerLayout as the root view.
Inside the DrawerLayout, add a layout for the main UI content and another view that contains the contents of the navigation drawer.

Reference:
https://developer.android.com/guide/navigation/navigation-ui

Sample pictures

Java code

package com.example.NavigationDrawer;

import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    public NavigationView navigationView;
    public DrawerLayout drawerLayout;
    public ActionBarDrawerToggle toggle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        drawerLayout = findViewById(R.id.drawerLayout);
        toggle = new ActionBarDrawerToggle(this, drawerLayout,R.string.open,R.string.close);

        drawerLayout.addDrawerListener(toggle);
        toggle.syncState();

        navigationView = findViewById(R.id.nav);
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {

                int id = menuItem.getItemId();
                switch (id)
                {
                    case R.id.one :
                        Toast.makeText(getApplicationContext(),"one",Toast.LENGTH_SHORT).show();
                        break;
                    case R.id.two :
                        Toast.makeText(getApplicationContext(),"two",Toast.LENGTH_SHORT).show();
                        break;
                    case R.id.three :
                        Toast.makeText(getApplicationContext(),"three",Toast.LENGTH_SHORT).show();
                        break;
                    case R.id.four :
                        Toast.makeText(getApplicationContext(),"four",Toast.LENGTH_SHORT).show();
                        break;
                }
                return true;
            }
        });
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(toggle.onOptionsItemSelected(item))
        {
            return true;
        }
        return super.onOptionsItemSelected(item);

    }

}

XML

Picasso and Glide

DIGIDIMENSION — Sat, 17 Dec 2022 20:14:36 +0000

Picasso and Glide, Using libraries in Android

Picasso:
A powerful image downloading and caching library for Android.
Images add much-needed context and visual flair to Android applications.
Picasso allows for hassle-free image loading in your application—often in one line of code!
Many common pitfalls of image loading on Android are handled automatically by Picasso:

Handling ImageView recycling and download cancelation in an adapter.
Complex image transformations with minimal memory use.
Automatic memory and disk caching.

Glide:
Glide is a fast and efficient open source media management and image loading framework for Android that wraps media decoding, memory and disk caching, and resource pooling into a simple and easy to use interface.
Glide supports fetching, decoding, and displaying video stills, images, and animated GIFs. Glide includes a flexible API that allows developers to plug in to almost any network stack. By default Glide uses a custom HttpUrlConnection based stack, but also includes utility libraries plug in to Google’s Volley project or Square’s OkHttp library instead.
Glide’s primary focus is on making scrolling any kind of a list of images as smooth and fast as possible, but Glide is also effective for almost any case where you need to fetch, resize, and display a remote image.

Sample pictures

Java code

package com.example.picasso_glide;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;
import com.bumptech.glide.Glide;
import com.bumptech.glide.load.resource.bitmap.RoundedCorners;
import com.squareup.picasso.Picasso;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ImageView image1 = findViewById(R.id.imageView1);
        ImageView image2 = findViewById(R.id.imageView2);

        String image1Url = "https://wallpapercave.com/wp/wp7911121.jpg";
        String image2Url = "https://wallpapercave.com/uwp/uwp552608.jpeg";


        Glide.with(this).load(image1Url)
                .transform(new RoundedCorners(30))
                .into(image1);

        Picasso.get().load(image2Url)
                .resize(600,500)
                .into(image2);

    }
}

XML

Splash Screen

DIGIDIMENSION — Sat, 17 Dec 2022 10:32:01 +0000

Splash Screen is usually the first screen when App is opened,
In this tutorial we create a splash screen with animation.

Sample pictures

Java code

package com.example.SplashScreen;

import android.content.Intent;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;


public class SplashScreen extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash_screen);

        StartAnim();

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {

                startActivity(new Intent(getApplicationContext(), MainActivity.class));

            }
        }, 4000);

    }

    void StartAnim(){
        TextView ta = findViewById(R.id.splash_text);

        Animation animation = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.rotate);
        ta.startAnimation(animation);
    }

    @Override
    protected void onPause() {
        super.onPause();
        finish();
    }

}

package com.example.SplashScreen;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

XML

Start activity for result

DIGIDIMENSION — Sat, 17 Dec 2022 10:04:21 +0000

Getting a result from an activity with using startActivityForResult() method.

Sample pictures

Java code

package com.example.startactivityforresult;

import android.app.Activity;
import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    Button button;
    public static final int REQUEST_CODE =  0X996;


    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == REQUEST_CODE){

            if(resultCode == Activity.RESULT_OK){

                String str = data.getStringExtra(Main2Activity.EXTRA_DATA);
                Toast.makeText(getApplicationContext(),str,Toast.LENGTH_LONG).show();
            }
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button = findViewById(R.id.button);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(MainActivity.this,Main2Activity.class);
                startActivityForResult(intent,REQUEST_CODE);
            }
        });

    }
}

package com.example.startactivityforresult;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class Main2Activity extends AppCompatActivity {

    TextView textView;
    public static final String EXTRA_DATA = "EXTRA_DATA";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        textView = findViewById(R.id.textView);

        textView.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                Intent data = new Intent();
                data.putExtra(EXTRA_DATA,"for result!!!!!!");
                setResult(Activity.RESULT_OK,data);
                finish();

            }
        });

    }
}

Intent and putExtra

DIGIDIMENSION — Tue, 13 Dec 2022 06:00:25 +0000

Switching between activities in Android and sending data.

Sample pictures

Java code

package com.example.IntentPutextra;
 
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 
public class MainActivity extends AppCompatActivity {
 
    private static final String TAG = "MainActivity";
    Button button;
    EditText editText;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        Log.i(TAG, "m1_onCreate: ");
 
        button = findViewById(R.id.button);
        editText = findViewById(R.id.editText);
 
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
 
                String str = editText.getText().toString();
 
                Intent intent = new Intent(MainActivity.this,Main2Activity.class);
 
                intent.putExtra("ET",str);
 
                startActivity(intent);
            }
        });
 
    }
 
    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "m1_onResume: ");
    }
 
    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "m1_onStop: ");
    }
 
    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "m1_onPause: ");
    }
}

package com.example.IntentPutextra;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class Main2Activity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    TextView textView;
    MainActivity mm = new MainActivity();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Log.i(TAG, "m2_onCreate: ");

        textView = findViewById(R.id.textView);
        Bundle bundle = getIntent().getExtras();

        if (bundle != null) {
            String s = bundle.getString("ET");
            textView.setText(s);
        }

    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "m2_onResume: ");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "m2_onStop: ");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "m2_onPause: ");
    }
}