Using your finger to draw : Touch « User Event « Android






Using your finger to draw

   
package app.test;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class Test extends Activity implements OnTouchListener {
  ImageView imageView;
  Bitmap bitmap;
  Canvas canvas;
  Paint paint;
  float downx = 0, downy = 0, upx = 0, upy = 0;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    imageView = (ImageView) this.findViewById(R.id.ImageView);

    Display currentDisplay = getWindowManager().getDefaultDisplay();
    float dw = currentDisplay.getWidth();
    float dh = currentDisplay.getHeight();

    bitmap = Bitmap.createBitmap((int) dw, (int) dh,
        Bitmap.Config.ARGB_8888);
    canvas = new Canvas(bitmap);
    paint = new Paint();
    paint.setColor(Color.GREEN);
    imageView.setImageBitmap(bitmap);

    imageView.setOnTouchListener(this);
  }

  public boolean onTouch(View v, MotionEvent event) {
    int action = event.getAction();
    switch (action) {
    case MotionEvent.ACTION_DOWN:
      downx = event.getX();
      downy = event.getY();
      break;
    case MotionEvent.ACTION_MOVE:
      break;
    case MotionEvent.ACTION_UP:
      upx = event.getX();
      upy = event.getY();
      canvas.drawLine(downx, downy, upx, upy, paint);
      imageView.invalidate();
      break;
    case MotionEvent.ACTION_CANCEL:
      break;
    default:
      break;
    }
    return true;
  }
}

   
    
    
  








Related examples in the same category

1.Report your Multitouch operation
2.Touch screen
3.Single Touch Test
4.Testing the Multitouch API
5.Demonstrates the handling of touch screen and trackball events to implement a simple painting app.
6.Demonstrates splitting touch events across multiple views within a view group.