Animate rotation of an image in Android

Question

• I have a gear image which I want to continuously rotate about a fixed point.

• Earlier I was accomplishing this by including the image in my Android

Answer 1

Make an XML class (suppose: rotate.xml) and place it in res/anim folder and then write the following code in it:

Then in your java class, do the following in OnCreate:

final Animation a = AnimationUtils.loadAnimation(CustomActivity.this,
                R.anim.rotate);
        a.setDuration(3000);
        gear00.startAnimation(a);

OR

To do it using bitmap, I hope the following sequence of code helps you:

Bitmap targetBitmap = Bitmap.createBitmap(targetWidth, targetHeight, config);
Canvas canvas = new Canvas(targetBitmap);
Matrix matrix = new Matrix();
matrix.setRotate(mRotation,source.getWidth()/2,source.getHeight()/2);
canvas.drawBitmap(source, matrix, new Paint());

If you check the following method from:

~frameworks\base\graphics\java\android\graphics\Bitmap.java

public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height,
        Matrix m, boolean filter)

this would explain what it does with rotation and translate.