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android實現(xiàn)簡單的畫畫板實例代碼

更新時間：2014年01月21日 17:18:57 作者：

畫畫板實現(xiàn)起來其實很簡單，我們只需要利用android給我們提供的Canvas類來操作就可以實現(xiàn)簡單的畫畫功能

直接看代碼，注釋都寫清楚了

public class MainActivity extends Activity {
private ImageView iv;
private Bitmap baseBitmap;
private Canvas canvas;
private Paint paint;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  this.iv = (ImageView) this.findViewById(R.id.iv);
  // 創(chuàng)建一張空白圖片
  baseBitmap = Bitmap.createBitmap(480, 640, Bitmap.Config.ARGB_8888);
  // 創(chuàng)建一張畫布
  canvas = new Canvas(baseBitmap);
  // 畫布背景為灰色
  canvas.drawColor(Color.GRAY);
  // 創(chuàng)建畫筆
  paint = new Paint();
  // 畫筆顏色為紅色
  paint.setColor(Color.RED);
  // 寬度5個像素
  paint.setStrokeWidth(5);
  // 先將灰色背景畫上
  canvas.drawBitmap(baseBitmap, new Matrix(), paint);
  iv.setImageBitmap(baseBitmap);

  iv.setOnTouchListener(new OnTouchListener() {
   int startX;
   int startY;

   @Override
   public boolean onTouch(View v, MotionEvent event) {
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
     // 獲取手按下時的坐標(biāo)
     startX = (int) event.getX();
     startY = (int) event.getY();
     break;
    case MotionEvent.ACTION_MOVE:
     // 獲取手移動后的坐標(biāo)
     int stopX = (int) event.getX();
     int stopY = (int) event.getY();
     // 在開始和結(jié)束坐標(biāo)間畫一條線
     canvas.drawLine(startX, startY, stopX, stopY, paint);
     // 實時更新開始坐標(biāo)
     startX = (int) event.getX();
     startY = (int) event.getY();
     iv.setImageBitmap(baseBitmap);
     break;
    }
    return true;
   }
  });
}

public void save(View view) {
  try {
   File file = new File(Environment.getExternalStorageDirectory(),
     System.currentTimeMillis() + ".jpg");
   OutputStream stream = new FileOutputStream(file);
   baseBitmap.compress(CompressFormat.JPEG, 100, stream);
   stream.close();
   // 模擬一個廣播，通知系統(tǒng)sdcard被掛載
   Intent intent = new Intent();
   intent.setAction(Intent.ACTION_MEDIA_MOUNTED);
   intent.setData(Uri.fromFile(Environment
     .getExternalStorageDirectory()));
   sendBroadcast(intent);

   Toast.makeText(this, "保存圖片成功", 0).show();
  } catch (Exception e) {
   Toast.makeText(this, "保存圖片失敗", 0).show();
   e.printStackTrace();
  }
}

}

簡單的布局文件

復(fù)制代碼代碼如下: