PRÁTICA 12 – AVANÇADO – CRIAR SEU PRÓPRIO COMPONENTE

Objetivo:

Criar um componente próprio, que estenda as funcionalidades de um componente existente.

Introdução

classe -> conjunto de códigos e informações que implementa uma funcionalidade

extends -> indica que uma determinada classe estende a funcionalidade de outra.

Tarefa:

Criar um imageView animado:

Programa 1 – Main class:

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

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}

Programa 1 – Layout para BouncingBall:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:weightSum="1">

    //Essa linha pode ser diferente de acordo com o nome do seu projeto!
    <empty.ammsoft.empty.BouncingBallView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/bouncingBall"
        android:layout_gravity="center_horizontal"
        android:adjustViewBounds="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

</RelativeLayout>

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

<RelativeLayout 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"

android:weightSum="1">

//Essa linha pode ser diferente de acordo com o nome do seu projeto!

<empty.ammsoft.empty.BouncingBallView

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:id="@+id/bouncingBall"

android:layout_gravity="center_horizontal"

android:adjustViewBounds="true"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true" />

</RelativeLayout>

Programa 1 – Clique em “new” -> “java class” e adicione uma nova classe chamada BouncingBallView (estende ImageView):

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

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.ImageView;

public class BouncingBallView extends ImageView {
    float ballX = 400;
    float ballY = 50;
    float incX = 1;
    float incY = 1;
    Paint paint;

    public BouncingBall(Context context, AttributeSet attrs) {
        super(context, attrs);

        paint = new Paint();
        paint.setColor(Color.BLACK);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (ballX > this.getWidth() - 30) {
            incX = incX * (-1);
        }

        if (ballX < 30) {
            incX = incX * (-1);
        }

        if (ballY > this.getHeight() - 30) {
            incY = incY * (-1);
        }

        if (ballY < 30) {
            incY = incY * (-1);
        }

        ballX = ballX + incX*10;
        ballY = ballY + incY*10;

        canvas.drawCircle((int)ballX,(int)ballY,30, paint);

        invalidate();
    }
}

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

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.util.AttributeSet;

import android.widget.ImageView;

public class BouncingBallView extends ImageView {

float ballX = 400;

float ballY = 50;

float incX = 1;

float incY = 1;

Paint paint;

public BouncingBall(Context context, AttributeSet attrs) {

super(context, attrs);

paint = new Paint();

paint.setColor(Color.BLACK);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

if (ballX > this.getWidth() - 30) {

incX = incX * (-1);

}

if (ballX < 30) {

incX = incX * (-1);

}

if (ballY > this.getHeight() - 30) {

incY = incY * (-1);

}

if (ballY < 30) {

incY = incY * (-1);

}

ballX = ballX + incX*10;

ballY = ballY + incY*10;

canvas.drawCircle((int)ballX,(int)ballY,30, paint);

invalidate();

}

Desafio: Adicione mais uma bolinha!

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

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.ImageView;

public class BouncingBallView extends ImageView {
    float ballX1 = 400;
    float ballY1 = 50;
    float incX1 = 1;
    float incY1 = 1;

    float ballX2 = 40;
    float ballY2 = 500;
    float incX2 = -1;
    float incY2 = -1;

    Paint paint;

    public BouncingBall(Context context, AttributeSet attrs) {
        super(context, attrs);

        paint = new Paint();
        paint.setColor(Color.BLACK);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        //BALL 1

        if (ballX1 > this.getWidth() - 30) {
            incX1 = incX1 * (-1);
        }

        if (ballX1 < 30) {
            incX1 = incX1 * (-1);
        }

        if (ballY1 > this.getHeight() - 30) {
            incY1 = incY1 * (-1);
        }

        if (ballY1 < 30) {
            incY1 = incY1 * (-1);
        }

        ballX1 = ballX1 + incX1*10;
        ballY1 = ballY1 + incY1*10;

        canvas.drawCircle((int)ballX1,(int)ballY1,30, paint);

        //BALL 2

        if (ballX2 > this.getWidth() - 30) {
            incX2 = incX2 * (-1);
        }

        if (ballX2 < 30) {
            incX2 = incX2 * (-1);
        }

        if (ballY2 > this.getHeight() - 30) {
            incY2 = incY2 * (-1);
        }

        if (ballY2 < 30) {
            incY2 = incY2 * (-1);
        }

        ballX2 = ballX2 + incX2*10;
        ballY2 = ballY2 + incY2*10;

        canvas.drawCircle((int)ballX2,(int)ballY2,30, paint);

        invalidate();
    }
}

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

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.util.AttributeSet;

import android.widget.ImageView;

public class BouncingBallView extends ImageView {

float ballX1 = 400;

float ballY1 = 50;

float incX1 = 1;

float incY1 = 1;

float ballX2 = 40;

float ballY2 = 500;

float incX2 = -1;

float incY2 = -1;

Paint paint;

public BouncingBall(Context context, AttributeSet attrs) {

super(context, attrs);

paint = new Paint();

paint.setColor(Color.BLACK);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

//BALL 1

if (ballX1 > this.getWidth() - 30) {

incX1 = incX1 * (-1);

}

if (ballX1 < 30) {

incX1 = incX1 * (-1);

}

if (ballY1 > this.getHeight() - 30) {

incY1 = incY1 * (-1);

}

if (ballY1 < 30) {

incY1 = incY1 * (-1);

}

ballX1 = ballX1 + incX1*10;

ballY1 = ballY1 + incY1*10;

canvas.drawCircle((int)ballX1,(int)ballY1,30, paint);

//BALL 2

if (ballX2 > this.getWidth() - 30) {

incX2 = incX2 * (-1);

}

if (ballX2 < 30) {

incX2 = incX2 * (-1);

}

if (ballY2 > this.getHeight() - 30) {

incY2 = incY2 * (-1);

}

if (ballY2 < 30) {

incY2 = incY2 * (-1);

}

ballX2 = ballX2 + incX2*10;

ballY2 = ballY2 + incY2*10;

canvas.drawCircle((int)ballX2,(int)ballY2,30, paint);

invalidate();

}