PRÁTICA 10 – CANVAS E DRAW

Objetivo:

Utilizar métodos Canvas e Bitmaps em um ImageView para desenhar diretamente na tela.

Introdução

Canvas -> Tela do Android.

BitMap -> Mapa de bits que representa uma imagem na tela do Android.

ImageView -> Local onde pode ser carregada (JPG por exemplo) ou gerada uma imagem.

Tarefa:

Criar tipos aplicações de desenho e gráficos:

Programa 1 – Design padrão com um imageView vazio (onde será desenhado):

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/layout"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Desenho!"
        android:id="@+id/textView4"
        android:layout_gravity="center_horizontal" />

    <ImageView
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:id="@+id/grafico"
        android:layout_gravity="center_horizontal"
        android:adjustViewBounds="true" />

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:id="@+id/layout"

android:orientation="vertical">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="Desenho!"

android:id="@+id/textView4"

android:layout_gravity="center_horizontal" />

<ImageView

android:layout_width="300dp"

android:layout_height="300dp"

android:id="@+id/grafico"

android:layout_gravity="center_horizontal"

android:adjustViewBounds="true" />

</LinearLayout>

Programa 1 – Alguns desenhos simples:

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    ImageView graphicImage;


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

        graphicImage = (ImageView) findViewById(R.id.grafico);

        Bitmap bitmap = Bitmap.createBitmap(300, 300, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(bitmap);

        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        paint.setColor(Color.BLACK);
        canvas.drawCircle(100,100,10, paint);

        paint.setColor(Color.RED);
        canvas.drawLine(100,100,200,200, paint);

        paint.setColor(Color.YELLOW);
        canvas.drawText("Desenho",100,200, paint);

        paint.setColor(Color.GREEN);
        canvas.drawRect(20,20,40,40,paint);

        graphicImage.setImageBitmap(bitmap);
    }
}

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

ImageView graphicImage;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

graphicImage = (ImageView) findViewById(R.id.grafico);

Bitmap bitmap = Bitmap.createBitmap(300, 300, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(bitmap);

Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

paint.setColor(Color.BLACK);

canvas.drawCircle(100,100,10, paint);

paint.setColor(Color.RED);

canvas.drawLine(100,100,200,200, paint);

paint.setColor(Color.YELLOW);

canvas.drawText("Desenho",100,200, paint);

paint.setColor(Color.GREEN);

canvas.drawRect(20,20,40,40,paint);

graphicImage.setImageBitmap(bitmap);

}

Programa 2 – Layout para fazer gráficos de parábolas:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:id="@+id/layout"
    android:orientation="vertical">

    <ImageView
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:id="@+id/grafico"
        android:layout_gravity="center_horizontal"
        android:adjustViewBounds="false" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Equação de Segundo Grau"
        android:id="@+id/textView4"
        android:layout_gravity="center_horizontal" />

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentBottom="true">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="a"
            android:id="@+id/textView" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/a"
            android:layout_weight="1"
            android:inputType="numberDecimal" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="b"
            android:id="@+id/textView3" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b"
            android:layout_weight="1"
            android:inputType="numberSigned|numberDecimal" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="c"
            android:id="@+id/textView2" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/c"
            android:layout_weight="1"
            android:inputType="numberSigned|numberDecimal" />

    </LinearLayout>

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="X1="
            android:id="@+id/x1"
            android:layout_weight="1" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="X2="
            android:id="@+id/x2"
            android:layout_weight="1" />

    </LinearLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Resolver"
        android:id="@+id/button2"
        android:layout_weight="1"
        android:layout_gravity="right"
        android:clickable="true"
        android:onClick="calculaSegundoGrau" />

</LinearLayout>

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<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

android:id="@+id/layout"

android:orientation="vertical">

<ImageView

android:layout_width="300dp"

android:layout_height="300dp"

android:id="@+id/grafico"

android:layout_gravity="center_horizontal"

android:adjustViewBounds="false" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="Equação de Segundo Grau"

android:id="@+id/textView4"

android:layout_gravity="center_horizontal" />

<LinearLayout

android:orientation="horizontal"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentTop="true"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_alignParentBottom="true">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="a"

android:id="@+id/textView" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/a"

android:layout_weight="1"

android:inputType="numberDecimal" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="b"

android:id="@+id/textView3" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/b"

android:layout_weight="1"

android:inputType="numberSigned|numberDecimal" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="c"

android:id="@+id/textView2" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/c"

android:layout_weight="1"

android:inputType="numberSigned|numberDecimal" />

</LinearLayout>

<LinearLayout

android:orientation="horizontal"

android:layout_width="match_parent"

android:layout_height="wrap_content">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="X1="

android:id="@+id/x1"

android:layout_weight="1" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="X2="

android:id="@+id/x2"

android:layout_weight="1" />

</LinearLayout>

<Button

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Resolver"

android:id="@+id/button2"

android:layout_weight="1"

android:layout_gravity="right"

android:clickable="true"

android:onClick="calculaSegundoGrau" />

</LinearLayout>

Programa 2 – Programa para fazer gráficos de parábolas:

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    ImageView graphicImage;

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

        graphicImage = (ImageView) findViewById(R.id.grafico);
    }

    public void drawGraphics(double a, double b, double c) {
        Bitmap bitmap = Bitmap.createBitmap(300, 300, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(bitmap);

        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        paint.setColor(Color.BLACK);

        canvas.drawLine(0,150,300,150, paint);
        canvas.drawLine(150,0,150,300, paint);

        paint.setColor(Color.BLUE);

        double x,y;

        double scaleX = 150;
        double scaleY = 150;

        //Escala de -20 a 20 (0.1 de precisao)
        for (int loop=-200;loop<200;loop++) {
            x = loop / 10d;
            y = a * x*x + b * x + c;

            x = x + scaleX;
            y = y + scaleY;

            canvas.drawPoint((float)x, (float)y, paint);
        }

        graphicImage.setImageBitmap(bitmap);
    }

    public void calculaSegundoGrau(View v) {
        EditText a_edit = (EditText) findViewById(R.id.a);
        EditText b_edit = (EditText) findViewById(R.id.b);
        EditText c_edit = (EditText) findViewById(R.id.c);
        TextView x1_text = (TextView) findViewById(R.id.x1);
        TextView x2_text = (TextView) findViewById(R.id.x2);

        x1_text.setText("X1 = ");
        x2_text.setText("X2 = ");

        if (a_edit.getText().length() == 0) {
            Toast.makeText(this, "Esqueceu o valor de a!",Toast.LENGTH_SHORT).show();
            return;
        }

        if (b_edit.getText().length() == 0) {
            Toast.makeText(this, "Esqueceu o valor de b!",Toast.LENGTH_SHORT).show();
            return;
        }

        if (c_edit.getText().length() == 0) {
            Toast.makeText(this, "Esqueceu o valor de c!",Toast.LENGTH_SHORT).show();
            return;
        }

        double a = Double.parseDouble(a_edit.getText().toString());
        double b = Double.parseDouble(b_edit.getText().toString());
        double c = Double.parseDouble(c_edit.getText().toString());

        double delta = b * b - 4*a*c;

        if (delta < 0) {
            Toast.makeText(this, "Delta menor que ZERO!",Toast.LENGTH_SHORT).show();
            return;
        }

        double x1 = -b + Math.sqrt(delta);
        double x2 = -b - Math.sqrt(delta);

        x1_text.setText("X1 = " + String.format("%.2f",x1));
        x2_text.setText("X2 = " + String.format("%.2f",x2));

        drawGraphics(a,b,c);
    }
}

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package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

ImageView graphicImage;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

graphicImage = (ImageView) findViewById(R.id.grafico);

}

public void drawGraphics(double a, double b, double c) {

Bitmap bitmap = Bitmap.createBitmap(300, 300, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(bitmap);

Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

paint.setColor(Color.BLACK);

canvas.drawLine(0,150,300,150, paint);

canvas.drawLine(150,0,150,300, paint);

paint.setColor(Color.BLUE);

double x,y;

double scaleX = 150;

double scaleY = 150;

//Escala de -20 a 20 (0.1 de precisao)

for (int loop=-200;loop<200;loop++) {

x = loop / 10d;

y = a * x*x + b * x + c;

x = x + scaleX;

y = y + scaleY;

canvas.drawPoint((float)x, (float)y, paint);

}

graphicImage.setImageBitmap(bitmap);

}

public void calculaSegundoGrau(View v) {

EditText a_edit = (EditText) findViewById(R.id.a);

EditText b_edit = (EditText) findViewById(R.id.b);

EditText c_edit = (EditText) findViewById(R.id.c);

TextView x1_text = (TextView) findViewById(R.id.x1);

TextView x2_text = (TextView) findViewById(R.id.x2);

x1_text.setText("X1 = ");

x2_text.setText("X2 = ");

if (a_edit.getText().length() == 0) {

Toast.makeText(this, "Esqueceu o valor de a!",Toast.LENGTH_SHORT).show();

return;

}

if (b_edit.getText().length() == 0) {

Toast.makeText(this, "Esqueceu o valor de b!",Toast.LENGTH_SHORT).show();

return;

}

if (c_edit.getText().length() == 0) {

Toast.makeText(this, "Esqueceu o valor de c!",Toast.LENGTH_SHORT).show();

return;

}

double a = Double.parseDouble(a_edit.getText().toString());

double b = Double.parseDouble(b_edit.getText().toString());

double c = Double.parseDouble(c_edit.getText().toString());

double delta = b * b - 4*a*c;

if (delta < 0) {

Toast.makeText(this, "Delta menor que ZERO!",Toast.LENGTH_SHORT).show();

return;

}

double x1 = -b + Math.sqrt(delta);

double x2 = -b - Math.sqrt(delta);

x1_text.setText("X1 = " + String.format("%.2f",x1));

x2_text.setText("X2 = " + String.format("%.2f",x2));

drawGraphics(a,b,c);

}

Desafio: Plote uma função seno e faça um Layout onde pode-se configurar a frequência em Hz:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/layout"
    android:orientation="vertical">

    <ImageView
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:id="@+id/grafico"
        android:layout_gravity="center_horizontal"
        android:adjustViewBounds="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Senóide"
        android:id="@+id/textView4"
        android:layout_gravity="center_horizontal" />

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentBottom="true">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="Amplitude"
            android:id="@+id/textView" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/amp"
            android:layout_weight="1"
            android:inputType="numberDecimal"
            android:text="1" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="Frequência (Hz)"
            android:id="@+id/textView2" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/freq"
            android:layout_weight="1"
            android:inputType="numberSigned|numberDecimal"
            android:text="1" />

    </LinearLayout>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:id="@+id/layout"

android:orientation="vertical">

<ImageView

android:layout_width="300dp"

android:layout_height="300dp"

android:id="@+id/grafico"

android:layout_gravity="center_horizontal"

android:adjustViewBounds="true" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="Senóide"

android:id="@+id/textView4"

android:layout_gravity="center_horizontal" />

<LinearLayout

android:orientation="horizontal"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentTop="true"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_alignParentBottom="true">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="Amplitude"

android:id="@+id/textView" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/amp"

android:layout_weight="1"

android:inputType="numberDecimal"

android:text="1" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="Frequência (Hz)"

android:id="@+id/textView2" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/freq"

android:layout_weight="1"

android:inputType="numberSigned|numberDecimal"

android:text="1" />

</LinearLayout>

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity implements View.OnFocusChangeListener {
    ImageView graphicImage;
    EditText editTextAmp;
    EditText editTextFreq;

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

        graphicImage = (ImageView) findViewById(R.id.grafico);
        editTextAmp = (EditText) findViewById(R.id.amp);
        editTextFreq = (EditText) findViewById(R.id.freq);

        editTextAmp.setOnFocusChangeListener(this);
        editTextFreq.setOnFocusChangeListener(this);
    }

    public void drawGraphics(double amp, double freq) {
        Bitmap bitmap = Bitmap.createBitmap(300, 300, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(bitmap);

        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        paint.setColor(Color.BLACK);

        canvas.drawLine(0,150,300,150, paint);
        canvas.drawLine(150,0,150,300, paint);

        paint.setColor(Color.BLUE);

        double y, xIni, plotX1, plotY1, plotX2, plotY2;

        xIni = -6;
        y = amp * Math.sin(2*Math.PI*freq*xIni);

        plotX1 = (xIni*50 + 150);
        plotY1 = (y*50 + 150);

        for (double x=xIni;x<6;x=x+0.01d) {
            y = amp * Math.sin(2*Math.PI*freq*(x));

            plotX2 = (x*50 + 150);
            plotY2 = (y*50 + 150);

            canvas.drawLine((float)plotX1, (float)plotY1, (float)plotX2, (float)plotY2, paint);

            plotX1 = plotX2;
            plotY1 = plotY2;
        }

        graphicImage.setImageBitmap(bitmap);
    }

    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        double amp = Double.parseDouble(editTextAmp.getText().toString());
        double freq = Double.parseDouble(editTextFreq.getText().toString());

        drawGraphics(amp,freq);
    }
}

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

import android.widget.ImageView;

public class MainActivity extends AppCompatActivity implements View.OnFocusChangeListener {

ImageView graphicImage;

EditText editTextAmp;

EditText editTextFreq;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

graphicImage = (ImageView) findViewById(R.id.grafico);

editTextAmp = (EditText) findViewById(R.id.amp);

editTextFreq = (EditText) findViewById(R.id.freq);

editTextAmp.setOnFocusChangeListener(this);

editTextFreq.setOnFocusChangeListener(this);

}

public void drawGraphics(double amp, double freq) {

Bitmap bitmap = Bitmap.createBitmap(300, 300, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(bitmap);

Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

paint.setColor(Color.BLACK);

canvas.drawLine(0,150,300,150, paint);

canvas.drawLine(150,0,150,300, paint);

paint.setColor(Color.BLUE);

double y, xIni, plotX1, plotY1, plotX2, plotY2;

xIni = -6;

y = amp * Math.sin(2*Math.PI*freq*xIni);

plotX1 = (xIni*50 + 150);

plotY1 = (y*50 + 150);

for (double x=xIni;x<6;x=x+0.01d) {

y = amp * Math.sin(2*Math.PI*freq*(x));

plotX2 = (x*50 + 150);

plotY2 = (y*50 + 150);

canvas.drawLine((float)plotX1, (float)plotY1, (float)plotX2, (float)plotY2, paint);

plotX1 = plotX2;

plotY1 = plotY2;

}

graphicImage.setImageBitmap(bitmap);

}

@Override

public void onFocusChange(View v, boolean hasFocus) {

double amp = Double.parseDouble(editTextAmp.getText().toString());

double freq = Double.parseDouble(editTextFreq.getText().toString());

drawGraphics(amp,freq);

}