Android Studio:

Hi everyone. How's it going?

I'm having trouble with calling the Matrix class into the Main Activity.

Basically, when the lock button is pressed, the matrix class should run/be active.

I'm not sure if I should use the resizable() method or create a new intent.

All other parts of the code appears to be working fine.

Please help!

Thanks For Understanding.

MainActivity class:

import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
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 b_enable, b_lock;

    static final int RESULT_ENABLE = 1;

    DevicePolicyManager devicePolicyManager;

    ComponentName componentName;

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

        b_enable = (Button) findViewById(R.id.b_enable);

        b_lock = (Button) findViewById(R.id.b_lock);

        devicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
        componentName = new ComponentName(MainActivity.this, Controller.class);

        boolean active = devicePolicyManager.isAdminActive(componentName);

        if(active)
        {
            b_enable.setText("DISABLE");
            b_lock.setVisibility(View.VISIBLE);


        }
        else
        {
            b_enable.setText("ENABLE");
            b_lock.setVisibility(View.GONE);

        }

        b_enable.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                boolean active = devicePolicyManager.isAdminActive(componentName);

                if (active)
                {
                   devicePolicyManager.removeActiveAdmin(componentName);
                    b_enable.setText("ENABLE");
                   b_lock.setVisibility(View.GONE);


                }
                else
                {
                    Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
                    intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);
                    intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "Allowing Device Admin Is Required!");
                    startActivityForResult(intent, RESULT_ENABLE);

                }
            }
        });

        b_lock.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view)
            {
                devicePolicyManager.lockNow();
            }
        });



    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        switch (requestCode)
        {
            case RESULT_ENABLE:

            if (resultCode == Activity.RESULT_OK)
            {
                b_enable.setText("DISABLE");
                b_lock.setVisibility(View.VISIBLE);
            }
            else
            {
                Toast.makeText(this, "FAILED!", Toast.LENGTH_SHORT).show();
            }
            return;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
}

Matrix class:

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import java.io.Serializable;
import java.util.Random;

public class Matrix extends View
{
    private static final Random random = new Random();
    private int width, height;
    private Canvas canvas;
    private Bitmap canvasBnp;
    private int fontSize = 15;
    private int columnSize;
    private char[] chars = "!@#$%^&*()_-+=|[]{}<>?/.,;:'~`".toCharArray();
    private int [] txtPostByColumn;
    private Paint paintTxt, paintBg, paintBgBmp, paintInitBg;



    public Matrix (Context context, AttributeSet attrs)
    {
        super(context, attrs);
        paintTxt = new Paint();
        paintTxt.setStyle(Paint.Style.FILL);
        paintTxt.setColor(Color.BLUE);
        paintTxt.setTextSize(15);

        paintBg = new Paint();
        paintBg.setStyle(Paint.Style.FILL);
        paintBg.setColor(Color.BLACK);
        paintBg.setAlpha(5);

        paintBgBmp = new Paint();
        paintBgBmp.setColor(Color.BLACK);

        paintInitBg = new Paint();
        paintInitBg.setColor(Color.BLACK);
        paintInitBg.setAlpha(255);
        paintInitBg.setStyle(Paint.Style.FILL);


    }



    @Override
    protected void onSizeChanged (int w, int h, int oldw, int oldh)
    {

        super.onSizeChanged(w, h, oldw, oldh);
        width = w;
        height = h;

        canvasBnp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        canvas = new Canvas(canvasBnp);
        canvas.drawRect(0, 0, width, height, paintInitBg);
        columnSize = width/fontSize;


        txtPostByColumn = new int[columnSize + 1];


        for ( int y = 0; y < columnSize; y++)
        {
            txtPostByColumn[y] = random.nextInt(height/2) + 1;

        }

    }



    private void drawText()
    {
        for (int i = 0; i < txtPostByColumn.length; i++)
        {
            canvas.drawText("" + chars[random.nextInt(chars.length)], i * fontSize, txtPostByColumn[i] * fontSize, paintTxt);

            if (txtPostByColumn[i] * fontSize > height && Math.random() > 0.975)
            {
                txtPostByColumn[i] = 0;

            }

            txtPostByColumn[i]++;


         }

    }


    private void drawCanvas()
    {
        canvas.drawRect(0, 0, width, height, paintBg);
        drawText();
    }



    @Override

    protected void onDraw(Canvas canvas)
    {
        super.onDraw(canvas);
        canvas.drawBitmap(canvasBnp, 0, 0, paintBgBmp);
        drawCanvas();
        invalidate();
    }






}