Dibujar en pantalla y realizar una captura

Programación | Tutoriales | Aplicaciones | Android |

Para un proyecto en el que estoy trabajando me han pedido una aplicación para Android que que permita pintar en pantalla y capturar la imagen. Os dejo el código por si a alguno le interesa. Primero creo la vista que capturará los eventos de pantalla y pintará en en canvas.

import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.drawable.Drawable;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.util.*;

public class DrawView extends View implements OnTouchListener {

    private static final String TAG = "DrawView";
    List points = new ArrayList();
    Paint paint = new Paint();
    List newLine = new ArrayList();
    private Boolean clearCanvas = false;

public DrawView(Context context, AttributeSet attrs){
    super(context, attrs);
    DrawViewFunction();
}
public DrawView(Context context) {
    super(context);
    	DrawViewFunction();
    }

public void DrawViewFunction()
{
    setFocusable(true);
    setFocusableInTouchMode(true);

    this.setOnTouchListener(this);

    paint.setColor(Color.BLACK);
    paint.setAntiAlias(true);
}

@Override
public void onDraw(Canvas canvas) {

	if(clearCanvas)
    {  // Choose the colour you want to clear with.
        canvas.drawColor(Color.WHITE);
        //canvas.drawColor(0, Mode.CLEAR);
        clearCanvas = false;    
        points.clear();
    }

	for (int i = 0; i<points.size(); i++) {
        Point newPoint = new Point();
        Point oldPoint = new Point();
        if (newLine.contains(i)||i==0){
            newPoint = points.get(i);
            oldPoint = newPoint;
        } else {
            newPoint = points.get(i);
            oldPoint = points.get(i-1);
        }

        canvas.drawLine(oldPoint.x, oldPoint.y, newPoint.x, newPoint.y, paint);
    }
}

public void clearCanvas()
{
	clearCanvas = true;
	invalidate();
}

public boolean onTouch(View view, MotionEvent event) {
    Point point = new Point();
    point.x = event.getX();
    point.y = event.getY();
    points.add(point);
    invalidate();
    Log.d(TAG, "point: " + point);
    if(event.getAction() == MotionEvent.ACTION_UP){
        // return super.onTouchEvent(event);
        newLine.add(points.size());
    }
    return true;
    }

public Bitmap getBitmap() {
    //Define a bitmap with the same size as the view

	View view = this;

    Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
    //Bind a canvas to it
    Canvas canvas = new Canvas(returnedBitmap);
    //Get the view's background
    Drawable bgDrawable =view.getBackground();
    if (bgDrawable!=null) 
        //has background drawable, then draw it on the canvas
        bgDrawable.draw(canvas);
    else 
        //does not have background drawable, then draw white background on the canvas
        canvas.drawColor(Color.WHITE);
    // draw the view on the canvas
    view.draw(canvas);
    //return the bitmap
    return returnedBitmap;
}

}

class Point {
    float x, y;

    @Override
    public String toString() {
        return x + ", " + y;
    }
}

Luego implementaré la actividad que meneja la vista pintable.

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity{

	Button btnTakePicture;
	Button btnClearDraw;
	DrawView vistaPintar;
	Bitmap capturaPantalla;
	ImageView vistaCaptura;

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

		btnTakePicture = (Button)findViewById(R.id.button1);
		btnClearDraw = (Button)findViewById(R.id.btnClear);
		vistaPintar = (DrawView) findViewById(R.id.drawView1);
		vistaCaptura = (ImageView) findViewById(R.id.imageView1);

		btnTakePicture.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				capturaPantalla = vistaPintar.getBitmap();
				Drawable drawable = new BitmapDrawable(capturaPantalla);
				vistaCaptura.setImageDrawable(drawable);
			}
		});

		btnClearDraw.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) { 
				vistaPintar.clearCanvas();
				vistaCaptura.setImageDrawable(null);
			}
		});
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

Espero que os sirva de ayuda