| package com.itheima.play; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Matrix; import android.graphics.Paint; import android.media.MediaPlayer; import android.os.Bundle; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.widget.ImageView; public class MainActivity extends Activity { private ImageView iv; // 可以修改的位图 private Bitmap alertBitmap; private Canvas canvas; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); iv = (ImageView) findViewById(R.id.iv); Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pre); // 创建一个空白的原图的拷贝 alertBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig()); canvas = new Canvas(alertBitmap); Paint paint = new Paint(); paint.setColor(Color.BLACK); canvas.drawBitmap(bitmap, new Matrix(), paint); iv.setImageBitmap(alertBitmap); iv.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN:// 手指按下屏幕 System.out.println("action down"); break; case MotionEvent.ACTION_MOVE:// 手指在屏幕上移动 int x = (int) event.getX(); int y = (int) event.getY(); System.out.println("设置("+x+","+y+")透明颜色"); for(int i=-4;i<5;i++){ for(int j=-4;j<5;j++){ try{ alertBitmap.setPixel(x+i, y+j, Color.TRANSPARENT); } catch (Exception e) { e.printStackTrace(); } } } iv.setImageBitmap(alertBitmap); break; case MotionEvent.ACTION_UP:// 手指离开屏幕 MediaPlayer.create(getApplicationContext(), R.raw.higirl).start(); break; } return true;//可以重复循环的处理事件 } }); } } |