應該是這樣的吧？

if(mImageView.getX()>iv_null_imageView.getX()){
? ?//往左移動
? ?translateAnimation = new TranslateAnimation(0.1f, -mImageView.getWidth(), 0.1f,0.1f );
? ?Toast.makeText(this,"往左移動",Toast.LENGTH_LONG).show();
}else ?if (mImageView.getX()<iv_null_imageView.getX()){
? ?//往右移動
? ?translateAnimation = new TranslateAnimation(0.1f, ?mImageView.getWidth(), 0.1f, 0.1f);
}else if (mImageView.getY()>iv_null_imageView.getY()){
? ?//往上移動
? ?translateAnimation = new TranslateAnimation(0.1f,0.1f, 0.1f, ?-mImageView.getHeight());
}else if (mImageView.getY()<iv_null_imageView.getY()){
? ?//往下移動
? ?translateAnimation = new TranslateAnimation(0.1f,0.1f, 0.1f, ?mImageView.getHeight());
}