Question

I am using translate animation to make imageview trace a path.Initially I am just making my imageview to translate through a particular set of points but it does not.here is my code in ondraw method:

@Override
    public void onDraw(Canvas canvas) {
         Log.w(this.getClass().getName(),"onDraw of Balls called");
      super.onDraw(canvas);
      mCanvas = canvas;



         canvas.drawLine(0, 240, 160, 0, mPaint);
         canvas.drawLine(160, 0, 320, 240, mPaint);

         mBal = (ImageView)findViewById(R.id.strike);
         TranslateAnimation mTrans = new TranslateAnimation(0, 240, 160, 0);
         mTrans.setDuration(6000);
         mTrans.setFillEnabled(true);
         mTrans.setFillAfter(true);
         mTrans.start();

    }

plz help.

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Edit 1:-

This is my modified code but the translation is still not working.PLz help

@Override
    public void onDraw(Canvas canvas) {

      Log.w(this.getClass().getName(),"onDraw of Balls called");

      BallsOnDraw(canvas);

    }

     void BallsOnDraw(Canvas canvas)
     {

            canvas.drawLine(0, 240, 160, 0, mPaint);
            canvas.drawLine(160, 0, 320, 240, mPaint);

            TranslateAnimation mTrans = new TranslateAnimation(0, 320, 0,240);

            mTrans.setDuration(6000);
            SitoliaActivity.mBal.startAnimation(mTrans);


     }

Answer 1

You are mixing custom classes with ImageViews and animations. IMHO you should use only one of the methods. Also I don’t see that you actually connect the TranslationAnimation with the ImageView itself.

So, one solution would be to use TranslateAnimation, but then you would need to call mBal.startAnimation(mTrans) instead of mTrans.start().

The other solution would be to use a custom view, override onDraw, and handle the animation yourself:

• save the current time (System.curentTimeMillis)
• draw the Bitmap directly to the Canvas using canvas.drawBitmap(bitmap, x, y, paint);
• update the coordinates based on the elapsed time
• if the animation should still run, call postInvalidateDelayed(40);

Here is an example custom view:

public class C extends View {

    private static final float FROM_X = 400;
    private static final float FROM_Y = 100;
    private static final float TO_X = 10;
    private static final float TO_Y = 400;
    private static final int DURATION = 2*1000; // 2 seconds

    private Bitmap mImage;
    private long mStart = -1;
    private Paint mPaint = new Paint();

    public C(Context context) {
        super(context);
        mImage = ((BitmapDrawable)context.getResources().getDrawable(R.drawable.icon)).getBitmap();
    }

    @Override
    public void onDraw(Canvas canvas) {
        boolean finished = false;
        if (mStart == -1) {
            // Time to start the animation
            mStart = SystemClock.uptimeMillis();
        }
        int elapsed = (int)(SystemClock.uptimeMillis() - mStart);
        if (elapsed >= DURATION) {
            elapsed = DURATION;
            finished = true;
        }
        float x = FROM_X + (TO_X - FROM_X) * elapsed / DURATION;
        float y = FROM_Y + (TO_Y - FROM_Y) * elapsed / DURATION;
        canvas.drawBitmap(mImage, x, y, mPaint);
        if (!finished) {
            postInvalidateDelayed(10);
        }
    }

}